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
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
BACKGROUND： The neuronal transient outward potassium channel has been shown to be highly associated with acetylcholine. However, the influence of acetylcholine on the transient outward potassium current in cerebral c...BACKGROUND： The neuronal transient outward potassium channel has been shown to be highly associated with acetylcholine. However, the influence of acetylcholine on the transient outward potassium current in cerebral cortical neurons remains poorly understood. OBJECTIVE： To investigate acetylcholine modulation on transient outward potassium current in rat parietal cortical neurons using the whole-cell patch-clamp technique. DESIGN, TIME AND SETTING： A neuroelectrophysiology study was performed at the Department of Physiology, Harbin Medical University between January 2005 and January 2006. MATERIALS： Wistar rats were provided by the Animal Research Center, the Second Hospital of Harbin Medical University; PC-IIC patch-clamp amplifier and IBBClamp data collection analysis system were provided by Huazhong University for Science and Technology, Wuhan, China; PP-83 microelectrode puller was purchased from Narrishage, Japan. METHODS： The parietal somatosensory cortical neurons were acutely dissociated, and the modulation of acetylcholine （0.1, 1, 10, 100 μmol/L） on transient outward potassium channel was recorded using the whole-cell patch-clamp technique. MAIN OUTCOME MEASURES： Influence of acetylcholine on transient outward potassium current, potassium channel activation, and inactivation. RESULTS： The inhibitory effect of acetylcholine on transient outward potassium current was dose- and voltage-dependent （P 〈 0.01）. Acetylcholine was found to significantly affect the activation process of transient outward potassium current, i.e., the activation curve of transient outward potassium current was left-shifted, while the inactivation curve was shifted to hyperpolarization. Acetylcholine significantly prolonged the time constant of recovery from inactivation of transient outward potassium current （P 〈 0.01）. CONCLUSION： These results suggest that acetylcholine inhibits transient outward potassium current by regulating activation and inactivation processes of the transient outward potassium channel.展开更多
Objective Allocryptopine （ALL） is an effective alkaloid of Corydalis decumbens （Thunb.） Pers. Papaveraceae and has proved to be an- ti-arrhythmic. The purpose of our study is to investigate the effects of ALL on t...Objective Allocryptopine （ALL） is an effective alkaloid of Corydalis decumbens （Thunb.） Pers. Papaveraceae and has proved to be an- ti-arrhythmic. The purpose of our study is to investigate the effects of ALL on transmural repolarizing ionic ingredients of outward potassium current （Ito） and slow delayed rectifier potassium current （IKs）. Methods The monophasic action potential （MAP） technique was used to record the MAP duration of the epicardium （Epi）, myocardium （M） and endocardium （Endo） of the rabbit heart and the whole cell patch clamp was used to record/to and IKs in cardiomyocytes of Epi, M and Endo layers that were isolated from rabbit ventricles. Results The effects of ALL on MAP of Epi, M and Endo layers were disequilibrium. ALL could effectively reduce the transmural dispersion of repolarization （TDR） in rabbit transmural ventricular wall. ALL decreased the current densities of/to and IKs in a voltage and concentration dependent way and narrowed the repolarizing differences among three layers. The analysis of gating kinetics showed ALL accelerated the channel activation ofIto in M layers and partly inhibit the channel openings of/to in Epi, M and Endo cells. On the other hand, ALL mainly slowed channel deactivation of IKs channel in Epi and Endo layers without affecting its activation. Conclusions Our study gives partially explanation about the mechanisms of tmnsmural inhibition of/to and IKs channels by ALL in rabbit myocardium. These findings provide novel perspective regarding the anti-arrhythmogenesis application of ALL in clinical settings.展开更多
Effects of La3+ and Eu3+ on outward potassium channels(K+out) in Vicia guard cells have been studied by patch clamping technique.Extracellular La3+ inhibited K+out currents with a half-inhibition concentration(IC50) o...Effects of La3+ and Eu3+ on outward potassium channels(K+out) in Vicia guard cells have been studied by patch clamping technique.Extracellular La3+ inhibited K+out currents with a half-inhibition concentration(IC50) of 81 μmol·L-1.Interestingly,intracellular La3+ activated K+out currents at a free concentration of 1.13 × 10-14 mol·L-1,and inhibited K+out currents at a free concentration of 5.86 × 10-14 mol·L-1.Extracellular Eu3+ also activated K+out currents at concentrations of 10 μmol·L-1 and 50 μmol·L-1,and inhibited K+out currents at concentrations of more than 1 mmol·L-1.The effects of La3+ and Eu3+ on K+out currents may contribute to regulation of the plant water status,which may be one of the mechanisms of the biological effect of rare earth elements.展开更多
Dear Editor,Abscisic acid （ABA） induces turgot loss and hence stomatal closure by promoting rapid net K^＋ efflux from guard cells （GCs） through outward-rectifying K^＋ （K^＋out） channels （Schroeder et al., 198...Dear Editor,Abscisic acid （ABA） induces turgot loss and hence stomatal closure by promoting rapid net K^＋ efflux from guard cells （GCs） through outward-rectifying K^＋ （K^＋out） channels （Schroeder et al., 1987; Blatt, 1990）. The mechanisms of ABA signaling in GCs are detailed elsewhere （see Munemasa et al., 2015; Weiner et al., 2010; Pandey et al., 2007）. Briefly, ABA binds to the PYR/ PYL/RCARs, a family of soluble steroidogenic acute regulatory- related lipid transfer （START） proteins, and, in turn, inactivates the downstream PP2C （type 2C protein phosphatase）, leading to the activation of SnRK2.6 （SNF1 [sucrose non-fermenting-1- related protein kinase]/OST1 [open stomata 1]） protein kinases.展开更多
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.
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.
基金Special Foundation for the Science and Technology Youth of Heilongjiang Province,No. QC07C95the Science and Technology Foundation Program of Heilongjiang Provincial Education Department,No.11531152the Postdoctoral Foundation of Heilongjiang Province,No. LRB 07-424
文摘BACKGROUND： The neuronal transient outward potassium channel has been shown to be highly associated with acetylcholine. However, the influence of acetylcholine on the transient outward potassium current in cerebral cortical neurons remains poorly understood. OBJECTIVE： To investigate acetylcholine modulation on transient outward potassium current in rat parietal cortical neurons using the whole-cell patch-clamp technique. DESIGN, TIME AND SETTING： A neuroelectrophysiology study was performed at the Department of Physiology, Harbin Medical University between January 2005 and January 2006. MATERIALS： Wistar rats were provided by the Animal Research Center, the Second Hospital of Harbin Medical University; PC-IIC patch-clamp amplifier and IBBClamp data collection analysis system were provided by Huazhong University for Science and Technology, Wuhan, China; PP-83 microelectrode puller was purchased from Narrishage, Japan. METHODS： The parietal somatosensory cortical neurons were acutely dissociated, and the modulation of acetylcholine （0.1, 1, 10, 100 μmol/L） on transient outward potassium channel was recorded using the whole-cell patch-clamp technique. MAIN OUTCOME MEASURES： Influence of acetylcholine on transient outward potassium current, potassium channel activation, and inactivation. RESULTS： The inhibitory effect of acetylcholine on transient outward potassium current was dose- and voltage-dependent （P 〈 0.01）. Acetylcholine was found to significantly affect the activation process of transient outward potassium current, i.e., the activation curve of transient outward potassium current was left-shifted, while the inactivation curve was shifted to hyperpolarization. Acetylcholine significantly prolonged the time constant of recovery from inactivation of transient outward potassium current （P 〈 0.01）. CONCLUSION： These results suggest that acetylcholine inhibits transient outward potassium current by regulating activation and inactivation processes of the transient outward potassium channel.
文摘Objective Allocryptopine （ALL） is an effective alkaloid of Corydalis decumbens （Thunb.） Pers. Papaveraceae and has proved to be an- ti-arrhythmic. The purpose of our study is to investigate the effects of ALL on transmural repolarizing ionic ingredients of outward potassium current （Ito） and slow delayed rectifier potassium current （IKs）. Methods The monophasic action potential （MAP） technique was used to record the MAP duration of the epicardium （Epi）, myocardium （M） and endocardium （Endo） of the rabbit heart and the whole cell patch clamp was used to record/to and IKs in cardiomyocytes of Epi, M and Endo layers that were isolated from rabbit ventricles. Results The effects of ALL on MAP of Epi, M and Endo layers were disequilibrium. ALL could effectively reduce the transmural dispersion of repolarization （TDR） in rabbit transmural ventricular wall. ALL decreased the current densities of/to and IKs in a voltage and concentration dependent way and narrowed the repolarizing differences among three layers. The analysis of gating kinetics showed ALL accelerated the channel activation ofIto in M layers and partly inhibit the channel openings of/to in Epi, M and Endo cells. On the other hand, ALL mainly slowed channel deactivation of IKs channel in Epi and Endo layers without affecting its activation. Conclusions Our study gives partially explanation about the mechanisms of tmnsmural inhibition of/to and IKs channels by ALL in rabbit myocardium. These findings provide novel perspective regarding the anti-arrhythmogenesis application of ALL in clinical settings.
基金Supported by the National Natural Science Foundation of China (Grant No. 20701028)
文摘Effects of La3+ and Eu3+ on outward potassium channels(K+out) in Vicia guard cells have been studied by patch clamping technique.Extracellular La3+ inhibited K+out currents with a half-inhibition concentration(IC50) of 81 μmol·L-1.Interestingly,intracellular La3+ activated K+out currents at a free concentration of 1.13 × 10-14 mol·L-1,and inhibited K+out currents at a free concentration of 5.86 × 10-14 mol·L-1.Extracellular Eu3+ also activated K+out currents at concentrations of 10 μmol·L-1 and 50 μmol·L-1,and inhibited K+out currents at concentrations of more than 1 mmol·L-1.The effects of La3+ and Eu3+ on K+out currents may contribute to regulation of the plant water status,which may be one of the mechanisms of the biological effect of rare earth elements.
文摘Dear Editor,Abscisic acid （ABA） induces turgot loss and hence stomatal closure by promoting rapid net K^＋ efflux from guard cells （GCs） through outward-rectifying K^＋ （K^＋out） channels （Schroeder et al., 1987; Blatt, 1990）. The mechanisms of ABA signaling in GCs are detailed elsewhere （see Munemasa et al., 2015; Weiner et al., 2010; Pandey et al., 2007）. Briefly, ABA binds to the PYR/ PYL/RCARs, a family of soluble steroidogenic acute regulatory- related lipid transfer （START） proteins, and, in turn, inactivates the downstream PP2C （type 2C protein phosphatase）, leading to the activation of SnRK2.6 （SNF1 [sucrose non-fermenting-1- related protein kinase]/OST1 [open stomata 1]） protein kinases.
