Objective:To observe the sustained expression of transient outward potassium channel related proteins at the end of the treatment and 30 days after the end of the treatment in rats,and to explore the sustained curativ...Objective:To observe the sustained expression of transient outward potassium channel related proteins at the end of the treatment and 30 days after the end of the treatment in rats,and to explore the sustained curative effect and mechanism of acupuncture combined with Xijingtongmai decoction in rats with myocardial infarction.Methods:Twenty of 130 male SD rats were random extracted as the control group,and the rest were used to establish myocardial infarction by fed with high-fat diet and then injected with isoproterenol.According to ECG,80 rats were successfully established.Then they were randomly divided into model group,acupuncture combined with Chinese medicine group,acupuncture group and Western medicine group.The content of bFGF protein was measured by ELISA.The protein contents of Kv1.4,Kv4.2,Kv4.3 and KChIP2 were measured by Western blot.Results:At the end of treatment,compared with the model group,the protein contents of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF in each treatment group increased,and the increase was most significant in the acupuncture combined with Chinese medicine group(P<0.05).At the end of treatment,compared with the model group,the protein contents of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF in each treatment group increased,and the increase was most significant in the acupuncture combined with Chinese medicine group(P<0.05).Compared with the treatment group at the end of treatment,the expression of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF protein in each treatment group 30 days after the end of treatment decreased slightly(P<0.05),but still higher than that of the model group at this time(P<0.05).The combination of acupuncture and Chinese medicine group decreased the least of them(P<0.05).Conclusion:The results showed that acupuncture combined with xijingtongmai decoction had a sustained good effect.Its sustained action mechanism may be achieved by continuously increasing the protein content of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF through transient outward potassium channel.展开更多
Objective Large-conductance calcium-activated potassium(BKCa)channel modulates vascular smooth muscle tone.In the present study,we tested the hypothesis that salt,one of the factors which significantly influence blood...Objective Large-conductance calcium-activated potassium(BKCa)channel modulates vascular smooth muscle tone.In the present study,we tested the hypothesis that salt,one of the factors which significantly influence blood pressure(BP),can regulate BKCa activity and then elevate blood pressure.Methods Male Sprague-Dawley rats aged 6 weeks were randomized into high salt diet group(HS)and control group,fed with high salt diet(containing 5% NaCl)and standard rat chow(containing 0.4% NaCl)respectively for 16 weeks.Tail systolic blood pressure(SBP),body weight(BW)and 24-hour urinary output were tested every 4 weeks.Content of urinary Na+ was detected using flame spectrophotometrical method.At the end of 16 weeks,all the rats were killed,the mesenteric arteries were obtained,and single mesenteric smooth muscle cells were isolated at once.The resting membrane potential(Em),the total potassium currents and the currents after perfusion with TEA solution of the cells were all recorded by whole cell patch clamp.The transcriptions of BKCa channel α and β1 subunits in mesenteric arterial vascular smooth muscle cells(VSMC)of each group were calculated by real-time RT-PCR.Results There was no difference in SBP and BW at each stage between control group and HS group;the urinary Na+ level in HS animals was elevated significantly after 4 weeks.The negative values of Em in HS group VSMCs were reduced compared with those in the control group.Transcriptions of β1 subunit of BKCa channels were decreased in HS group,but α subunit transcriptions did not differ between the two groups.Whole cell potassium currents did not differ between HS and control groups,but BKCa currents of HS group VSMCs were lower than those of control group ones.Conclusion Even without elevating SBP,salt-loading can still modulate the expression and activity of BKCa channel in the mesenteric arterial VSMC and elevate vascular tone.展开更多
OBJECTIVE Stroke has become the top ten leading cause of death in China.Isch⁃emic stroke accounts for 85%of stroke cases,and insufficiency of cerebral blood supply caused by atherosclerosis is one of the important cau...OBJECTIVE Stroke has become the top ten leading cause of death in China.Isch⁃emic stroke accounts for 85%of stroke cases,and insufficiency of cerebral blood supply caused by atherosclerosis is one of the important causes of ischemic stroke.Therefore,it is of posi⁃tive significance to study the molecular mecha⁃nism of stroke injury caused by hypoperfusion in the search for drug targets.Voltage-dependent potassium channels are a family of potassium channels widely expressed in the central ner⁃vous system.However,their roles in neurogene⁃sis after stroke insults have not been clearly illus⁃trated.The purpose of this experiment is to explore the expression changes of different sub⁃families of voltage-dependent potassium chan⁃nels after the occurrence of ischemic stroke and their influence on neuroregeneration,to study the molecular mechanism of stroke injury caused by hypoperfusion,and to find potential targets for drug therapy of ischemic stroke.METHODS C57BL/6 mice aged 7-8 weeks and C17.2 cells were used in vivo and in vitro in the experiment.The mice in the experimental group were suf⁃fered from bilateral common carotid artery occlu⁃sion(BCCO)for 1 h and reperfusion for 7 d.In the control group,bilateral carotid artery was dis⁃sected without occlusion.Behavioral assay of suspension test were performed to assess the motor deficits of the mice.In this assay,the time of the first drop(latency),the number of drops within one minute(frequency),and the final scores were recorded as the results of athletic ability.A lower score indicated more severe motor damage of the mice.TTC staining was used to observe the cerebral infarction areas caused by ligation of bilateral common carotid arteries.After seven days,mice were sacrificed and brain tissue protein samples were collected for real-time quantitative PCR(RT-PCR)and Western blotting test to detect the changes of potassium channel subfamily expression levels in different brain regions.Neuronal injuries in all brain regions were detected using Nissl staining methods 7 d following model establishment.To detect the effects and the underlying mechanism of the related potassium channel on neurogene⁃sis,recombinant plasmids of the potassium chan⁃nels were transfected in cultured C17.2 neural stem cells.Afterwards,oxygen glucose depriva⁃tion experiments were performed.RESULTS Behavioral tests showed that BCCO can cause impaired motor performance.TTC staining showed that cerebral infarction existed in the stri⁃atum region,and the motor function decline caused by the injury in this region was consistent with the behavioral experiment results which veri⁃fied the effectiveness of our surgical operation.Nissl staining revealed a large amount of neuronal cell necrosis in the cortex and striatum regions,and dense neuronal cells in the lateral ventricular limbic region,suggesting that neurogenesis may have occurred in this region.The results of real-time quantitative RT-PCR showed that among the detected potassium channels distributed in the measured nervous system,the expression of voltage-dependent potassium channel Kv4.2 decreased significantly in all brain regions after stroke,suggesting that it may be involved in the pathological process of stroke.Immunohisto⁃chemical staining showed that there was neuro⁃genesis in the subgranular zone(SGZ)and sub⁃ventricular zone(SVZ)of the mice,and Kv4.2 expression was significantly changed in the regions,suggesting that it may be involved in the regulation of neuro regeneration after stroke.The transfected Kv4.2 plasmid enhanced the dif⁃ferentiation of the C17.2 neural stem cells to neu⁃rons and astrocytes under normoxia and the oxy⁃gen-glucose deprivation,suggesting that Kv4.2 may induce the differentiation of neural stem cells after stroke.Kv4.2 could induce the neural stem cells to differentiate into neurons in vitro and in vivo,and Western blotting assay showed that Kv4.2 could up-regulate the expression level of ERK1/2,p-ERK1/2,p-STAT3,NGF,p-TtkA,and BDNF.Moreover,the calcium ions and CAMKⅡwas also increased by Kv4.2 in vitro.CONCLUSION BCCO insults can induce the expressions of the potassium channels in the brains,among which the expression of Kv4.2 is down-regulated in the cerebral cortex,hippocam⁃pus and striatum.In vitro experiments confirmed that Kv4.2 can induce the differentiation of C17.2 neural stem cells into neurons and astrocytes under the condition of normoxia and oxygen-glucose deprivation.We concluded that Kv4.2 possibly promoted neurogenesis through ERK1/2/STAT3,NGF/TrkA,and Ca2+/CAMKⅡsignal pathways after stroke.Regulating the physiologi⁃cal functions of Kv4.2 channel might contribute to the rehabilitation of neuronal damage after stroke.展开更多
Objective:To study the effect of combination of acupuncture and medicine on the expression of ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in rats with myocardial infarction,and to study the poss...Objective:To study the effect of combination of acupuncture and medicine on the expression of ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in rats with myocardial infarction,and to study the possible mechanism of combination of acupuncture and medicine on the improvement of myocardial infarction,so as to provide experimental data basis for the development of new treatment methods for myocardial infarction.Methods:65 healthy male SD rats were randomly selected as the control group.The other rats were fed with high-fat food for three weeks.The rats in the control group were injected with normal saline subcutaneously,and the other rats were injected with isoproterenol hydrochloride in the same way.Through ECG comparison,40 successful Mi rats were randomly divided into model group,acupuncture group,western medicine group and acupuncture drug combination group,with 10 rats in each group.After the corresponding treatment,the ECG changes of rats in each group were observed,the pathological changes of rat cardiomyocytes were observed by HE staining,and the expression of ATP sensitive potassium channel(Kir6.1,Kir6.2)protein was detected by Western blot.Results:compared with the control group,40 experimental specimens in the experimental group showed significant changes in cardiomyocyte protein The expression of Kir6.1 and Kir6.2 increased,and the difference was statistically significant.After treatment,compared with the model group,the protein expression of Kir6.1 and Kir6.2 in cardiomyocytes of Western medicine group,acupuncture group and acupuncture drug combination group showed a downward trend,among which the decline degree of acupuncture drug combination group was the most obvious,and the difference was statistically significant.The decline degree of acupuncture group and Western medicine group was not significant,and there was no significant difference Conclusion:acupuncture combined with medicine has a significant effect on improving myocardial infarction in rats,which may be related to the expression of ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in rat cardiomyocytes.展开更多
Objectives Ischemia induced arrhythmia(ventricular tachycardia/ventricular fibrillation) is one of the major causes of death.Potassium channels change are likely to be responsible for the ischemia-related arrhythmias....Objectives Ischemia induced arrhythmia(ventricular tachycardia/ventricular fibrillation) is one of the major causes of death.Potassium channels change are likely to be responsible for the ischemia-related arrhythmias.Cardiac potassium current is the major outward current involved in cardiac repolarization.The properties of potassium channels have been intensively studied.Here,we investigated the association between ischemia induced arrhythmia and potassium channels genetic variations.Methods 23 patients with ventricular tachycardia/ventricular fibrillation induced by ischemia were selected as objects.5ML peripheral blood were taken from each person,from which DNA was extracted us- ing a standard enzymatic phenol-chloroform method.Candidate genes(HERG、KCNJ2、KCNQ1、Mink、Mirp1、Kir2.1、KV4.3、Kir3.1、KV1.5、Kir6.1、Kir6.2、Kir2.1) Were screened for potassium channels gene mutations with direct sequencing methods.Results Here 4 potassium channels gene mutations have been discovered.In the gene coding for the ATP-sensitive K^+ channels subunit Kir6.2,there is a change from valine to isoleucine at the position of 326(V326I).At the position 448,arginine substitutes proline(P448R) in the KC-NQ1 gene.In the gene KCNJ2 two mutations have been found(P156L,Q193H).Conclusions This study implicated that there is a high relationship between ischemia induced arrhythmia and the mutation of potassium channels.In order to identify the precisely relationship there is need functional analysis.展开更多
AIM: To study the expression of ether à go-go (Eag1) potassium channel in colorectal cancer and the relation- ship between their expression and clinico-pathological features. METHODS: The expression levels of Eag...AIM: To study the expression of ether à go-go (Eag1) potassium channel in colorectal cancer and the relation- ship between their expression and clinico-pathological features. METHODS: The expression levels of Eag1 protein were determined in 76 cancer tissues with paired non- cancerous matched tissues as well as 9 colorectal adenoma tissues by immunohistochemistry. Eag1 mRNA expression was detected in 13 colorectal cancer tissues with paired non-cancerous matched tissues and 4 colorectal adenoma tissues as well as two colorectal cancer cell lines (LoVo and HT-29) by reverse transcription PCR. RESULTS: The frequency of positive expression of Eag1 protein was 76.3% (58/76) and Eag1 mRNA was 76.9% (10/13) in colorectal cancer tissue. Expression level of Eag1 protein was dependent on the tumor size, lymphatic node metastasis, other organ metastases and Dukes’ stage (P < 0.05), while not dependent on age, sex, site and degree of differentiation. Eag1 protein and mRNA were negative in normal colorectal tissue, and absolutely negative in colorectal adenomas except that one case was positively stained for Eag1 protein. CONCLUSION: Eag1 protein and mRNA are aberrantly expressed in colorectal cancer and occasionally expressed in colorectal adenoma. The high frequency of expression of Eag1 in tumors and the restriction of normal expression to the brain suggest the potential of this protein for diagnostic, prognostic and therapeutic purposes.展开更多
Remodeling of ion channels is an important mechanism of arrhythmia induced by heart failure (HF).We investigated the expression of potassium channel encoding genes in the ventricles of rabbit established by volumeover...Remodeling of ion channels is an important mechanism of arrhythmia induced by heart failure (HF).We investigated the expression of potassium channel encoding genes in the ventricles of rabbit established by volumeoverload operation followed with pressure-overload.The reversible effect of these changes with bisoprolol was also evaluated.The HF group exhibited left ventricular enlargement,systolic dysfunction,prolongation of corrected QT interval (QTc),and increased plasma brain natriuretic peptide levels in the HF rabbits.Several potassium channel subunit encoding genes were consistently down-regulated in the HF rabbits.After bisoprolol treatment,heart function was improved significantly and QTc was shortened.Additionally,the mRNA expression of potassium channel subunit genes could be partially reversed.The down-regulated expression of potassium channel subunits Kv4.3,Kv1.4,KvLQT1,minK and Kir 2.1 may contribute to the prolongation of action potential duration in the heart of rabbits induced by volume combined with pressure overload HF.Bisoprolol could partially reverse these down-regulations and improve heart function.展开更多
The influence of hypoxia on the activity of voltage-gated potassium channel in pulmonary artery smooth muscle cells(PASMCs) of rats and its roles in the pathogenesis of chronic pulmonary heart disease were investigate...The influence of hypoxia on the activity of voltage-gated potassium channel in pulmonary artery smooth muscle cells(PASMCs) of rats and its roles in the pathogenesis of chronic pulmonary heart disease were investigated. Eighty male Sprague-Dawley rats were randomly allocated into control group(n=10), acute hypoxic group(n=10), and chronic hypoxic groups(n=60). The chronic hypoxic groups were randomly divided into 6 subgroups(n=10 each) according to the chronic hypoxic periods.The rats in the control group were kept in room air and those in acute hypoxic group in hypoxia environmental chamber for 8 h. The rats in chronic hypoxic subgroups were kept in hypoxia environmental chamber for 8 h per day for 5, 10, 15, 20, 25, and 30 days, respectively. The mean pulmonary arterial pressure(mPAP), right ventricular hypertrophy index(RVHI), and the current of voltage-gated potassium channel(IK) in PASMCs were measured. Results showed that both acute and chronic hypoxia could decrease the IK in PASMCs of rats and the I-V relationship downward shifted to the right. And the peak IK density at +60mV decreased with prolongation of hypoxia exposure. No significant difference was noted in the density of IK(at +60 mV) and I-V relationship between control group and chronic hypoxic subgroup exposed to hypoxia for 5 days(P>0.05), but there was a significant difference between control group and chronic hypoxic subgroup exposed to hypoxia for 10 days(P<0.05). Significant differences were noted in the IK density(at +60 mV) and I-V relationships between control group and chronic hypoxic subgroups exposed to hypoxia for 20 days and 30 days(P<0.01). Compared with control rats, the mPAP and RVHI were significantly increased after chronic exposure to hypoxia for 10 days(P<0.05), which were further increased with prolongation of hypoxia exposure, and there were significant differences between control group and chronic hypoxic subgroups exposed to hypoxia for 20 days and 30 days(P<0.01). Both the mPAP and the RVHI were negatively correlated with the density of IK(r=–0.89769 and –0.94476, respectively, both P<0.01). It is concluded that exposure to hypoxia may cause decreased activity of voltage-gated potassium channel, leading to hypoxia pulmonary vasoconstriction(HPV). Sustained HPV may result in chronic pulmonary hypertension, even chronic pulmonary heart disease, contributing to the pathogenesis of chronic pulmonary heart disease.展开更多
Hypoxic pulmonary hypertension(HPH) is a syndrome characterized by the increase of pulmonary vascular tone and the structural remodeling of peripheral pulmonary arteries.The aim of specific therapies for hypoxic pulmo...Hypoxic pulmonary hypertension(HPH) is a syndrome characterized by the increase of pulmonary vascular tone and the structural remodeling of peripheral pulmonary arteries.The aim of specific therapies for hypoxic pulmonary hypertension is to reduce pulmonary vascular resistance,reverse pulmonary vascular remodeling,and thereby improving right ventricular function.Iptakalim,a lipophilic para-amino compound with a low molecular weight,has been demonstrated to be a new selective ATP-sensitive potassium(K ATP) channel opener via pharmacological,electrophysiological,biochemical studies,and receptor binding tests.In hypoxia-induced animal models,iptakalim decreases the elevated mean pressure in pulmonary arteries,and attenuates remodeling in the right ventricle,pulmonary arteries and airways.Furthermore,iptakalim has selective antihypertensive effects,selective vasorelaxation effects on smaller arteries,and protective effects on endothelial cells,but no effects on the central nervous,respiratory,digestive or endocrine systems at therapeutic dose.Our previous studies demonstrated that iptakalim inhibited the effects of endothelin-1,reduced the intracellular calcium concentration and inhibited the proliferation of pulmonary artery smooth muscle cells.Since iptakalim has been shown safe and effective in both experimental animal models and phase I clinical trials,it can be a potential candidate of HPH in the future.展开更多
Chlorogenic acid(5-caffeoylquinic acid, CGA) is a phenolic compound that is found ubiquitously in plants, fruits and vegetables and is formed via the esterification of caffeic acid and quinic acid. In addition to its ...Chlorogenic acid(5-caffeoylquinic acid, CGA) is a phenolic compound that is found ubiquitously in plants, fruits and vegetables and is formed via the esterification of caffeic acid and quinic acid. In addition to its notable biological functions against cardiovascular diseases, type-2 diabetes and inflammatory conditions, CGA was recently hypothesized to be an alternative for the treatment of neurological diseases such as Alzheimer's disease and neuropathic pain disorders. However, its mechanism of action is unclear.Voltage-gated potassium channel(Kv) is a crucial factor in the electro-physiological processes of sensory neurons. Kv has also been identified as a potential therapeutic target for inflammation and neuropathic pain disorders. In this study, we analysed the effects of CGA on the two main subtypes of Kv in trigeminal ganglion neurons, namely, the IK,Aand IK,Vchannels. Trigeminal ganglion(TRG)neurons were acutely disassociated from the rat TRG, and two different doses of CGA(0.2 and 1 mmol·L21) were applied to the cells.Whole-cell patch-clamp recordings were performed to observe alterations in the activation and inactivation properties of the IK,Aand IK,Vchannels. The results demonstrated that 0.2 mmol·L21CGA decreased the peak current density of IK,A. Both 0.2 mmol·L21and1 mmol·L21CGA also caused a significant reduction in the activation and inactivation thresholds of IK,Aand IK,V. CGA exhibited a strong effect on the activation and inactivation velocities of IK,Aand IK,V. These findings provide novel evidence explaining the biological effects of CGA, especially regarding its neurological effects.展开更多
Catilan extracted from Leiurus quinquestriatus is a specific ion channel blocker.It can specifically bind chloride channels of glioma cells and kill these tumor cells.The questions remain as to whether antigliomatin,t...Catilan extracted from Leiurus quinquestriatus is a specific ion channel blocker.It can specifically bind chloride channels of glioma cells and kill these tumor cells.The questions remain as to whether antigliomatin,the extract from scorpion venom of Buthus martensii Karsch in China,can inhibit glioma growth,and whether this inhibition is correlated with ion channels of tumor cells.The present study treated rat C6 glioma cells with 0.8,1.2,and 1.6 μg/mL antigliomatin for 20 hours.Whole-cell patch clamp technique showed that antigliomatin delayed rectifier potassium channels of C6 glioma cells.Antigliomatin inhibited tumor growth,which could potentially involve potassium channels of tumor cells.展开更多
Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The e...Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The experiment revealed that the amplitude of transient outward potassium channel current was reduced.The maximum activated current densities of control group and exposure group were 163.62±20.68 pA/pF and 98.74±16.57 pA/pF(n=12,P<0.01) respectively.The static magnetic field exposure affected the activation and inactivation process of transient outward potassium channel current.Due to the magnetic field exposure,the half-activation voltage of the activation curves changed from 5.59±1.96 mV to 27.87±7.24 mV(n=12,P<0.05) ,and the slope factor changed from 19.43±2.11 mV to 25.87±4.22 mV(n=12,P<0.05) .The half-inactivation voltage of the inactivation curves also changed from-56.09±0.89 mV to-57.16±1.10 mV(n=12,P>0.05) and the slope factor of the inactivation curves from 8.69±0.80 mV to 10.87±1.02 mV(n=12,P<0.05) .The results show that the static magnetic field can change the characteristics of transient outward K+ channel,and affect the physiological functions of neurons.展开更多
The expression of stretch-activated potassium channel TREK-1 mRNA and protein of hypertrophic myocardium was measured. Using a model of hypertrophy induced by coarctation of abdominal aorta in male Wistar rats, the ex...The expression of stretch-activated potassium channel TREK-1 mRNA and protein of hypertrophic myocardium was measured. Using a model of hypertrophy induced by coarctation of abdominal aorta in male Wistar rats, the expression of TREK-1 mRNA and protein was detected by using semi-quantitative RT-PCR and Western blot respectively. At 4th and 8th week after constriction of the abdominal aorta, rats developed significant left ventricular hypertrophy. As compared to sham-operated group, stretch-activated potassium channel TREK-1 mRNA was strongly expressed and protein was up-regulated in operation groups (P<0.05). It was concluded that the expression of TREK-1 was up-regulated in hypertrophic myocardium induced by chronic pressure overload in Wistar rats.展开更多
Although previous studies have shown the neuroprotective effects of the adenosine triphosphate(ATP)-sensitive potassium(KATP) channel opener against ischemic neuronal damage,little is known about the mechanisms involv...Although previous studies have shown the neuroprotective effects of the adenosine triphosphate(ATP)-sensitive potassium(KATP) channel opener against ischemic neuronal damage,little is known about the mechanisms involved.Phosphatidylinositol-3 kinase(PI3K)/v-akt murine thy-moma viral oncogene homolog(Akt) and Bcl-2 are thought to be important factors that mediate neuroprotection.The present study investigated the effects of KATP openers on hypoxia-induced PC12 cell apoptosis,as well as mRNA and protein expression of Akt and Bcl-2.Results demon-strated that pretreatment of PC12 cells with pinacidil,a KATP opener,resulted in decreased PC12 cell apoptosis following hypoxia,as detected by Annexin-V fluorescein isothiocyanate/propidium iodide double staining flow cytometry.In addition,mRNA and protein expression of phosphory-lated Akt(p-Akt) and Bcl-2 increased,as detected by immunofluorescence,Western blot analysis,and reverse-transcription polymerase chain reaction.The protective effect of this preconditioning was attenuated by glipizide,a selective KATP blocker.These results demonstrate for the first time that the protective mechanisms of KATP openers on PC12 cell apoptosis following hypoxia could result from activation of the PI3K/Akt signaling pathway,which further activates expression of the downstream Bcl-2 gene.展开更多
In order to provide pertinent evidence of ion channel with immune response in the fish,whole cell patch-clamp technique was employed for potassium ion channel study in turbot(Scophthalmus maximus) . Lymphocytes were i...In order to provide pertinent evidence of ion channel with immune response in the fish,whole cell patch-clamp technique was employed for potassium ion channel study in turbot(Scophthalmus maximus) . Lymphocytes were isolated by Percoll density gradient centrifugation from peripheral blood samples,and electrophysiological characters of the channel were analyzed. In the recorded cells,activated voltage of the channels was-42.5 ± 3.7 mV and the average peak current was 313.12 ± 28.2 pA. The channel was identified as voltage dependent,the current was outward and it could be inhibited by 10 mmol/dm 3 TEA or 5 mmol/dm 3 4-AP,a specific potassium channel inhibitor,identifying the existence of potassium channel in peripheral lymphocytes of the turbot.展开更多
基金Key project of Liaoning provincial science and technology foundation(No.20180530079)。
文摘Objective:To observe the sustained expression of transient outward potassium channel related proteins at the end of the treatment and 30 days after the end of the treatment in rats,and to explore the sustained curative effect and mechanism of acupuncture combined with Xijingtongmai decoction in rats with myocardial infarction.Methods:Twenty of 130 male SD rats were random extracted as the control group,and the rest were used to establish myocardial infarction by fed with high-fat diet and then injected with isoproterenol.According to ECG,80 rats were successfully established.Then they were randomly divided into model group,acupuncture combined with Chinese medicine group,acupuncture group and Western medicine group.The content of bFGF protein was measured by ELISA.The protein contents of Kv1.4,Kv4.2,Kv4.3 and KChIP2 were measured by Western blot.Results:At the end of treatment,compared with the model group,the protein contents of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF in each treatment group increased,and the increase was most significant in the acupuncture combined with Chinese medicine group(P<0.05).At the end of treatment,compared with the model group,the protein contents of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF in each treatment group increased,and the increase was most significant in the acupuncture combined with Chinese medicine group(P<0.05).Compared with the treatment group at the end of treatment,the expression of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF protein in each treatment group 30 days after the end of treatment decreased slightly(P<0.05),but still higher than that of the model group at this time(P<0.05).The combination of acupuncture and Chinese medicine group decreased the least of them(P<0.05).Conclusion:The results showed that acupuncture combined with xijingtongmai decoction had a sustained good effect.Its sustained action mechanism may be achieved by continuously increasing the protein content of Kv1.4,Kv4.2,Kv4.3,KChIP2 and bFGF through transient outward potassium channel.
文摘Objective Large-conductance calcium-activated potassium(BKCa)channel modulates vascular smooth muscle tone.In the present study,we tested the hypothesis that salt,one of the factors which significantly influence blood pressure(BP),can regulate BKCa activity and then elevate blood pressure.Methods Male Sprague-Dawley rats aged 6 weeks were randomized into high salt diet group(HS)and control group,fed with high salt diet(containing 5% NaCl)and standard rat chow(containing 0.4% NaCl)respectively for 16 weeks.Tail systolic blood pressure(SBP),body weight(BW)and 24-hour urinary output were tested every 4 weeks.Content of urinary Na+ was detected using flame spectrophotometrical method.At the end of 16 weeks,all the rats were killed,the mesenteric arteries were obtained,and single mesenteric smooth muscle cells were isolated at once.The resting membrane potential(Em),the total potassium currents and the currents after perfusion with TEA solution of the cells were all recorded by whole cell patch clamp.The transcriptions of BKCa channel α and β1 subunits in mesenteric arterial vascular smooth muscle cells(VSMC)of each group were calculated by real-time RT-PCR.Results There was no difference in SBP and BW at each stage between control group and HS group;the urinary Na+ level in HS animals was elevated significantly after 4 weeks.The negative values of Em in HS group VSMCs were reduced compared with those in the control group.Transcriptions of β1 subunit of BKCa channels were decreased in HS group,but α subunit transcriptions did not differ between the two groups.Whole cell potassium currents did not differ between HS and control groups,but BKCa currents of HS group VSMCs were lower than those of control group ones.Conclusion Even without elevating SBP,salt-loading can still modulate the expression and activity of BKCa channel in the mesenteric arterial VSMC and elevate vascular tone.
文摘OBJECTIVE Stroke has become the top ten leading cause of death in China.Isch⁃emic stroke accounts for 85%of stroke cases,and insufficiency of cerebral blood supply caused by atherosclerosis is one of the important causes of ischemic stroke.Therefore,it is of posi⁃tive significance to study the molecular mecha⁃nism of stroke injury caused by hypoperfusion in the search for drug targets.Voltage-dependent potassium channels are a family of potassium channels widely expressed in the central ner⁃vous system.However,their roles in neurogene⁃sis after stroke insults have not been clearly illus⁃trated.The purpose of this experiment is to explore the expression changes of different sub⁃families of voltage-dependent potassium chan⁃nels after the occurrence of ischemic stroke and their influence on neuroregeneration,to study the molecular mechanism of stroke injury caused by hypoperfusion,and to find potential targets for drug therapy of ischemic stroke.METHODS C57BL/6 mice aged 7-8 weeks and C17.2 cells were used in vivo and in vitro in the experiment.The mice in the experimental group were suf⁃fered from bilateral common carotid artery occlu⁃sion(BCCO)for 1 h and reperfusion for 7 d.In the control group,bilateral carotid artery was dis⁃sected without occlusion.Behavioral assay of suspension test were performed to assess the motor deficits of the mice.In this assay,the time of the first drop(latency),the number of drops within one minute(frequency),and the final scores were recorded as the results of athletic ability.A lower score indicated more severe motor damage of the mice.TTC staining was used to observe the cerebral infarction areas caused by ligation of bilateral common carotid arteries.After seven days,mice were sacrificed and brain tissue protein samples were collected for real-time quantitative PCR(RT-PCR)and Western blotting test to detect the changes of potassium channel subfamily expression levels in different brain regions.Neuronal injuries in all brain regions were detected using Nissl staining methods 7 d following model establishment.To detect the effects and the underlying mechanism of the related potassium channel on neurogene⁃sis,recombinant plasmids of the potassium chan⁃nels were transfected in cultured C17.2 neural stem cells.Afterwards,oxygen glucose depriva⁃tion experiments were performed.RESULTS Behavioral tests showed that BCCO can cause impaired motor performance.TTC staining showed that cerebral infarction existed in the stri⁃atum region,and the motor function decline caused by the injury in this region was consistent with the behavioral experiment results which veri⁃fied the effectiveness of our surgical operation.Nissl staining revealed a large amount of neuronal cell necrosis in the cortex and striatum regions,and dense neuronal cells in the lateral ventricular limbic region,suggesting that neurogenesis may have occurred in this region.The results of real-time quantitative RT-PCR showed that among the detected potassium channels distributed in the measured nervous system,the expression of voltage-dependent potassium channel Kv4.2 decreased significantly in all brain regions after stroke,suggesting that it may be involved in the pathological process of stroke.Immunohisto⁃chemical staining showed that there was neuro⁃genesis in the subgranular zone(SGZ)and sub⁃ventricular zone(SVZ)of the mice,and Kv4.2 expression was significantly changed in the regions,suggesting that it may be involved in the regulation of neuro regeneration after stroke.The transfected Kv4.2 plasmid enhanced the dif⁃ferentiation of the C17.2 neural stem cells to neu⁃rons and astrocytes under normoxia and the oxy⁃gen-glucose deprivation,suggesting that Kv4.2 may induce the differentiation of neural stem cells after stroke.Kv4.2 could induce the neural stem cells to differentiate into neurons in vitro and in vivo,and Western blotting assay showed that Kv4.2 could up-regulate the expression level of ERK1/2,p-ERK1/2,p-STAT3,NGF,p-TtkA,and BDNF.Moreover,the calcium ions and CAMKⅡwas also increased by Kv4.2 in vitro.CONCLUSION BCCO insults can induce the expressions of the potassium channels in the brains,among which the expression of Kv4.2 is down-regulated in the cerebral cortex,hippocam⁃pus and striatum.In vitro experiments confirmed that Kv4.2 can induce the differentiation of C17.2 neural stem cells into neurons and astrocytes under the condition of normoxia and oxygen-glucose deprivation.We concluded that Kv4.2 possibly promoted neurogenesis through ERK1/2/STAT3,NGF/TrkA,and Ca2+/CAMKⅡsignal pathways after stroke.Regulating the physiologi⁃cal functions of Kv4.2 channel might contribute to the rehabilitation of neuronal damage after stroke.
基金Key Project of Liaoning Provincial Science and Technology Foundation(No.20180530079)。
文摘Objective:To study the effect of combination of acupuncture and medicine on the expression of ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in rats with myocardial infarction,and to study the possible mechanism of combination of acupuncture and medicine on the improvement of myocardial infarction,so as to provide experimental data basis for the development of new treatment methods for myocardial infarction.Methods:65 healthy male SD rats were randomly selected as the control group.The other rats were fed with high-fat food for three weeks.The rats in the control group were injected with normal saline subcutaneously,and the other rats were injected with isoproterenol hydrochloride in the same way.Through ECG comparison,40 successful Mi rats were randomly divided into model group,acupuncture group,western medicine group and acupuncture drug combination group,with 10 rats in each group.After the corresponding treatment,the ECG changes of rats in each group were observed,the pathological changes of rat cardiomyocytes were observed by HE staining,and the expression of ATP sensitive potassium channel(Kir6.1,Kir6.2)protein was detected by Western blot.Results:compared with the control group,40 experimental specimens in the experimental group showed significant changes in cardiomyocyte protein The expression of Kir6.1 and Kir6.2 increased,and the difference was statistically significant.After treatment,compared with the model group,the protein expression of Kir6.1 and Kir6.2 in cardiomyocytes of Western medicine group,acupuncture group and acupuncture drug combination group showed a downward trend,among which the decline degree of acupuncture drug combination group was the most obvious,and the difference was statistically significant.The decline degree of acupuncture group and Western medicine group was not significant,and there was no significant difference Conclusion:acupuncture combined with medicine has a significant effect on improving myocardial infarction in rats,which may be related to the expression of ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in rat cardiomyocytes.
文摘Objectives Ischemia induced arrhythmia(ventricular tachycardia/ventricular fibrillation) is one of the major causes of death.Potassium channels change are likely to be responsible for the ischemia-related arrhythmias.Cardiac potassium current is the major outward current involved in cardiac repolarization.The properties of potassium channels have been intensively studied.Here,we investigated the association between ischemia induced arrhythmia and potassium channels genetic variations.Methods 23 patients with ventricular tachycardia/ventricular fibrillation induced by ischemia were selected as objects.5ML peripheral blood were taken from each person,from which DNA was extracted us- ing a standard enzymatic phenol-chloroform method.Candidate genes(HERG、KCNJ2、KCNQ1、Mink、Mirp1、Kir2.1、KV4.3、Kir3.1、KV1.5、Kir6.1、Kir6.2、Kir2.1) Were screened for potassium channels gene mutations with direct sequencing methods.Results Here 4 potassium channels gene mutations have been discovered.In the gene coding for the ATP-sensitive K^+ channels subunit Kir6.2,there is a change from valine to isoleucine at the position of 326(V326I).At the position 448,arginine substitutes proline(P448R) in the KC-NQ1 gene.In the gene KCNJ2 two mutations have been found(P156L,Q193H).Conclusions This study implicated that there is a high relationship between ischemia induced arrhythmia and the mutation of potassium channels.In order to identify the precisely relationship there is need functional analysis.
基金Acknowledgments We thank Dr Emily Liman (University of Southern California, USA) for providing the pGEMHE vector for the Xenopus oocyte experiments. We also thank Dr Richer Gaber (Northwestern Uni- versity, USA) for providing the yeast mutant strain with K+ transport deficiency. We are grateful to Dr Rainer Hedrich (University of Wurzburg, Germany) for critical discussion. This work was supported by the National Natural Science Foundation of China (grant no. 30830013 to WHW), the Beijing Municipal Education Commission (grant no. YB20081001901 to WHW) and the Program of Introducing Talents of Discipline to Universities (grant no. B06003 to WHW).
文摘AIM: To study the expression of ether à go-go (Eag1) potassium channel in colorectal cancer and the relation- ship between their expression and clinico-pathological features. METHODS: The expression levels of Eag1 protein were determined in 76 cancer tissues with paired non- cancerous matched tissues as well as 9 colorectal adenoma tissues by immunohistochemistry. Eag1 mRNA expression was detected in 13 colorectal cancer tissues with paired non-cancerous matched tissues and 4 colorectal adenoma tissues as well as two colorectal cancer cell lines (LoVo and HT-29) by reverse transcription PCR. RESULTS: The frequency of positive expression of Eag1 protein was 76.3% (58/76) and Eag1 mRNA was 76.9% (10/13) in colorectal cancer tissue. Expression level of Eag1 protein was dependent on the tumor size, lymphatic node metastasis, other organ metastases and Dukes’ stage (P < 0.05), while not dependent on age, sex, site and degree of differentiation. Eag1 protein and mRNA were negative in normal colorectal tissue, and absolutely negative in colorectal adenomas except that one case was positively stained for Eag1 protein. CONCLUSION: Eag1 protein and mRNA are aberrantly expressed in colorectal cancer and occasionally expressed in colorectal adenoma. The high frequency of expression of Eag1 in tumors and the restriction of normal expression to the brain suggest the potential of this protein for diagnostic, prognostic and therapeutic purposes.
基金supported by the State Key Program of the National Natural Science Foundation of China (No. 30830051)
文摘Remodeling of ion channels is an important mechanism of arrhythmia induced by heart failure (HF).We investigated the expression of potassium channel encoding genes in the ventricles of rabbit established by volumeoverload operation followed with pressure-overload.The reversible effect of these changes with bisoprolol was also evaluated.The HF group exhibited left ventricular enlargement,systolic dysfunction,prolongation of corrected QT interval (QTc),and increased plasma brain natriuretic peptide levels in the HF rabbits.Several potassium channel subunit encoding genes were consistently down-regulated in the HF rabbits.After bisoprolol treatment,heart function was improved significantly and QTc was shortened.Additionally,the mRNA expression of potassium channel subunit genes could be partially reversed.The down-regulated expression of potassium channel subunits Kv4.3,Kv1.4,KvLQT1,minK and Kir 2.1 may contribute to the prolongation of action potential duration in the heart of rabbits induced by volume combined with pressure overload HF.Bisoprolol could partially reverse these down-regulations and improve heart function.
文摘The influence of hypoxia on the activity of voltage-gated potassium channel in pulmonary artery smooth muscle cells(PASMCs) of rats and its roles in the pathogenesis of chronic pulmonary heart disease were investigated. Eighty male Sprague-Dawley rats were randomly allocated into control group(n=10), acute hypoxic group(n=10), and chronic hypoxic groups(n=60). The chronic hypoxic groups were randomly divided into 6 subgroups(n=10 each) according to the chronic hypoxic periods.The rats in the control group were kept in room air and those in acute hypoxic group in hypoxia environmental chamber for 8 h. The rats in chronic hypoxic subgroups were kept in hypoxia environmental chamber for 8 h per day for 5, 10, 15, 20, 25, and 30 days, respectively. The mean pulmonary arterial pressure(mPAP), right ventricular hypertrophy index(RVHI), and the current of voltage-gated potassium channel(IK) in PASMCs were measured. Results showed that both acute and chronic hypoxia could decrease the IK in PASMCs of rats and the I-V relationship downward shifted to the right. And the peak IK density at +60mV decreased with prolongation of hypoxia exposure. No significant difference was noted in the density of IK(at +60 mV) and I-V relationship between control group and chronic hypoxic subgroup exposed to hypoxia for 5 days(P>0.05), but there was a significant difference between control group and chronic hypoxic subgroup exposed to hypoxia for 10 days(P<0.05). Significant differences were noted in the IK density(at +60 mV) and I-V relationships between control group and chronic hypoxic subgroups exposed to hypoxia for 20 days and 30 days(P<0.01). Compared with control rats, the mPAP and RVHI were significantly increased after chronic exposure to hypoxia for 10 days(P<0.05), which were further increased with prolongation of hypoxia exposure, and there were significant differences between control group and chronic hypoxic subgroups exposed to hypoxia for 20 days and 30 days(P<0.01). Both the mPAP and the RVHI were negatively correlated with the density of IK(r=–0.89769 and –0.94476, respectively, both P<0.01). It is concluded that exposure to hypoxia may cause decreased activity of voltage-gated potassium channel, leading to hypoxia pulmonary vasoconstriction(HPV). Sustained HPV may result in chronic pulmonary hypertension, even chronic pulmonary heart disease, contributing to the pathogenesis of chronic pulmonary heart disease.
基金supported by National Major Scientific and Technological Special Project for"Significant New Drugs Development"(2011ZX09302-003-02)
文摘Hypoxic pulmonary hypertension(HPH) is a syndrome characterized by the increase of pulmonary vascular tone and the structural remodeling of peripheral pulmonary arteries.The aim of specific therapies for hypoxic pulmonary hypertension is to reduce pulmonary vascular resistance,reverse pulmonary vascular remodeling,and thereby improving right ventricular function.Iptakalim,a lipophilic para-amino compound with a low molecular weight,has been demonstrated to be a new selective ATP-sensitive potassium(K ATP) channel opener via pharmacological,electrophysiological,biochemical studies,and receptor binding tests.In hypoxia-induced animal models,iptakalim decreases the elevated mean pressure in pulmonary arteries,and attenuates remodeling in the right ventricle,pulmonary arteries and airways.Furthermore,iptakalim has selective antihypertensive effects,selective vasorelaxation effects on smaller arteries,and protective effects on endothelial cells,but no effects on the central nervous,respiratory,digestive or endocrine systems at therapeutic dose.Our previous studies demonstrated that iptakalim inhibited the effects of endothelin-1,reduced the intracellular calcium concentration and inhibited the proliferation of pulmonary artery smooth muscle cells.Since iptakalim has been shown safe and effective in both experimental animal models and phase I clinical trials,it can be a potential candidate of HPH in the future.
基金supported by the National Science Foundation of China (Grant No. 81000456)the Science and Technology Department of Sichuan Province (Grant No. 2009SZ0171)
文摘Chlorogenic acid(5-caffeoylquinic acid, CGA) is a phenolic compound that is found ubiquitously in plants, fruits and vegetables and is formed via the esterification of caffeic acid and quinic acid. In addition to its notable biological functions against cardiovascular diseases, type-2 diabetes and inflammatory conditions, CGA was recently hypothesized to be an alternative for the treatment of neurological diseases such as Alzheimer's disease and neuropathic pain disorders. However, its mechanism of action is unclear.Voltage-gated potassium channel(Kv) is a crucial factor in the electro-physiological processes of sensory neurons. Kv has also been identified as a potential therapeutic target for inflammation and neuropathic pain disorders. In this study, we analysed the effects of CGA on the two main subtypes of Kv in trigeminal ganglion neurons, namely, the IK,Aand IK,Vchannels. Trigeminal ganglion(TRG)neurons were acutely disassociated from the rat TRG, and two different doses of CGA(0.2 and 1 mmol·L21) were applied to the cells.Whole-cell patch-clamp recordings were performed to observe alterations in the activation and inactivation properties of the IK,Aand IK,Vchannels. The results demonstrated that 0.2 mmol·L21CGA decreased the peak current density of IK,A. Both 0.2 mmol·L21and1 mmol·L21CGA also caused a significant reduction in the activation and inactivation thresholds of IK,Aand IK,V. CGA exhibited a strong effect on the activation and inactivation velocities of IK,Aand IK,V. These findings provide novel evidence explaining the biological effects of CGA, especially regarding its neurological effects.
基金the Science and Technology Development Program of Jilin Province, No. 20050407-6
文摘Catilan extracted from Leiurus quinquestriatus is a specific ion channel blocker.It can specifically bind chloride channels of glioma cells and kill these tumor cells.The questions remain as to whether antigliomatin,the extract from scorpion venom of Buthus martensii Karsch in China,can inhibit glioma growth,and whether this inhibition is correlated with ion channels of tumor cells.The present study treated rat C6 glioma cells with 0.8,1.2,and 1.6 μg/mL antigliomatin for 20 hours.Whole-cell patch clamp technique showed that antigliomatin delayed rectifier potassium channels of C6 glioma cells.Antigliomatin inhibited tumor growth,which could potentially involve potassium channels of tumor cells.
基金Supported by National Natural Science Foundation of China(No. 60674111)
文摘Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The experiment revealed that the amplitude of transient outward potassium channel current was reduced.The maximum activated current densities of control group and exposure group were 163.62±20.68 pA/pF and 98.74±16.57 pA/pF(n=12,P<0.01) respectively.The static magnetic field exposure affected the activation and inactivation process of transient outward potassium channel current.Due to the magnetic field exposure,the half-activation voltage of the activation curves changed from 5.59±1.96 mV to 27.87±7.24 mV(n=12,P<0.05) ,and the slope factor changed from 19.43±2.11 mV to 25.87±4.22 mV(n=12,P<0.05) .The half-inactivation voltage of the inactivation curves also changed from-56.09±0.89 mV to-57.16±1.10 mV(n=12,P>0.05) and the slope factor of the inactivation curves from 8.69±0.80 mV to 10.87±1.02 mV(n=12,P<0.05) .The results show that the static magnetic field can change the characteristics of transient outward K+ channel,and affect the physiological functions of neurons.
文摘The expression of stretch-activated potassium channel TREK-1 mRNA and protein of hypertrophic myocardium was measured. Using a model of hypertrophy induced by coarctation of abdominal aorta in male Wistar rats, the expression of TREK-1 mRNA and protein was detected by using semi-quantitative RT-PCR and Western blot respectively. At 4th and 8th week after constriction of the abdominal aorta, rats developed significant left ventricular hypertrophy. As compared to sham-operated group, stretch-activated potassium channel TREK-1 mRNA was strongly expressed and protein was up-regulated in operation groups (P<0.05). It was concluded that the expression of TREK-1 was up-regulated in hypertrophic myocardium induced by chronic pressure overload in Wistar rats.
基金the Natural Science Foundation of Liaoning Province,No.20052097,2008225010
文摘Although previous studies have shown the neuroprotective effects of the adenosine triphosphate(ATP)-sensitive potassium(KATP) channel opener against ischemic neuronal damage,little is known about the mechanisms involved.Phosphatidylinositol-3 kinase(PI3K)/v-akt murine thy-moma viral oncogene homolog(Akt) and Bcl-2 are thought to be important factors that mediate neuroprotection.The present study investigated the effects of KATP openers on hypoxia-induced PC12 cell apoptosis,as well as mRNA and protein expression of Akt and Bcl-2.Results demon-strated that pretreatment of PC12 cells with pinacidil,a KATP opener,resulted in decreased PC12 cell apoptosis following hypoxia,as detected by Annexin-V fluorescein isothiocyanate/propidium iodide double staining flow cytometry.In addition,mRNA and protein expression of phosphory-lated Akt(p-Akt) and Bcl-2 increased,as detected by immunofluorescence,Western blot analysis,and reverse-transcription polymerase chain reaction.The protective effect of this preconditioning was attenuated by glipizide,a selective KATP blocker.These results demonstrate for the first time that the protective mechanisms of KATP openers on PC12 cell apoptosis following hypoxia could result from activation of the PI3K/Akt signaling pathway,which further activates expression of the downstream Bcl-2 gene.
基金The National Natural Science Foundation of China under contract Nos 40476060 and 40876089the State Key Basic Research Program under contract No. 2006CB101805
文摘In order to provide pertinent evidence of ion channel with immune response in the fish,whole cell patch-clamp technique was employed for potassium ion channel study in turbot(Scophthalmus maximus) . Lymphocytes were isolated by Percoll density gradient centrifugation from peripheral blood samples,and electrophysiological characters of the channel were analyzed. In the recorded cells,activated voltage of the channels was-42.5 ± 3.7 mV and the average peak current was 313.12 ± 28.2 pA. The channel was identified as voltage dependent,the current was outward and it could be inhibited by 10 mmol/dm 3 TEA or 5 mmol/dm 3 4-AP,a specific potassium channel inhibitor,identifying the existence of potassium channel in peripheral lymphocytes of the turbot.