Effects Of ATP Sensitive potassium channel opener on the mRNA and pro- tein expressions of caspase-12 after cerebral ischemia-reperfusion in rats

Objective To investigate effects of K_ATP opener on the expressions of caspase-12 mRNA and protein, and to explore the role of endoplasmic reticulum （ER） stress pathway in the mechanism of K_ATP opener protecting against neuronal apoptosis after cerebral ischemia-reperfusion. Methods Two hundred rats were randomly divided into four groups： sham operation group, ischemia-reperfusion group, K_ATP opener group, and K_ATP blocker group. The middle cerebral artery occlusion （MCAO） model was established by intraluminal suture occlusion method; neuronal apoptosis was detected by TUNEL staining. The mRNA and protein expressions of caspase-12 were detected by semi-quantitative RT-PCR and immunohisto-chemical staining, respectively. Results In ischemia-reperfusion group, K_ATP opener group and K_ATP blocker group, the number of apoptotic cells and the mRNA and protein expressions of caspase-12 gradually increased following cerebral reperfusion, and reached the peak at 24 h. In K_ATP opener group, The number of apoptotic cells was significantly less than that in ischemia-reperfusion group and K_ATP blocker group at 12 h, 24 h, 48 h and 72 h （P 〈 0.05 or P 〈 0.01）; while the mRNA and protein levels of caspase-12 were significantly less than those in ischemia-reperfusion group and K_ATP blocker group at all times （P 〈 0.05 or P〈0.01）. There were no differences between the ischemia-reperfusion group and K_ATP blocker group at each time （P〉 0.05）. Conclusion K_ATP opener may protect neurons from apoptosis following the cerebral ischemia-reperfusion by inhibiting ER stress pathway.

CO_2-triggered gelation for mobility control and channeling blocking during CO_2 flooding processes

CO2 flooding is regarded as an important method for enhanced oil recovery （EOR） and greenhouse gas control. However, the heterogeneity prevalently dis- tributed in reservoirs inhibits the performance of this technology. The sweep efficiency can be significantly reduced especially in the presence of ＂thief zones＂. Hence, gas channeling blocking and mobility control are important technical issues for the success of CO2 injection. Normally, crosslinked gels have the potential to block gas channels, but the gelation time control poses challenges to this method. In this study, a new method for selectively blocking CO2 channeling is proposed, which is based on a type of CO2-sensitive gel system （modified polyacry- lamide-methenamine-resorcinol gel system） to form gel in situ. A CO2-sensitive gel system is when gelation or solidification will be triggered by CO2 in the reservoir to block gas channels. The CO2-sensitivity of the gel system was demonstrated in parallel bottle tests of gel in N2 and CO2 atmospheres. Sand pack flow experiments were con- ducted to investigate the shutoff capacity of the gel system under different conditions. The injectivity of the gel system was studied via viscosity measurements. The results indi- cate that this gel system was sensitive to CO2 and had good performance of channeling blocking in porous media. Advantageous viscosity-temperature characteristics were achieved in this work. The effectiveness for EOR in heterogeneous formations based on this gel system was demonstrated using displacement tests conducted in double sand packs. The experimental results can provide guideli- nes for the deployment of theCO2-sensitive gel system for field applications.

Effects of acupuncture combined with Kaijingtongmai Decoction on ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in myocardial infarction rats

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.

Induction of pancreatic duct cells of neonatal rats into insulin-producing cells with fetal bovine serum: A natural protocol and its use for patch clamp experiments

AIM： To induce the pancreatic duct cells into endocrine cells with a new natural protocol for electrophysiological study. METHODS： The pancreatic duct cells of neonatal rats were isolated, cultured and induced into endocrine ceils with 15% fetal bovine serum for a period of 20 d. During this period, insulin secretion, MTT value, and morphological change of neonatal and adult pancreatic islet cells were comparatively investigated. Pancreatic β-cells were identified by morphological and electrophysiological characteristics, while ATP sensitive potassium channels （KATP）, voltage-dependent potassium channels （Kv）, and voltage-dependent calcium channels （KcA） in β-cells were identified by patch clamp technique. RESULTS： After incubation with fetal bovine serum, the neonatal duct cells budded out, changed from duct-like cells into islet clusters. In the first 4 d, MTT value and insulin secretion increased slowly （MTT value from 0.024 ±0.003 to 3.028±0.003, insulin secretion from 2.6±0.6 to 3.1±0.8 mIU/L）. Then MTT value and insulin secretion increased quickly from d 5 to d 10 （MTT value from 0.028 ±0.003 to 0.052±0.008, insulin secretion from 3.1±0.8 to 18.3±2.6 mIU/L）, then reached high plateau （MTT value 〉0.052±0.008, insulin secretion 〉18.3±2.6 mIU/L）. In contrast, for the isolated adult pancreatic islet cells, both insulin release and MTT value were stable in the first 4 d （MTT value from 0.029±0.01 to 0.031±0.011, insulin secretion from 13.9±3.1 to 14.3±3.3 mIU/L）, but afterwards they reduced gradually （MTT value 〈0.031 ±0.011, insulin secretion 〈8.2±1.5 mIU/L）, and the pancreatic islet cells became dispersed, broken or atrophied correspondingly. The differentiated neonatal cells were identified as pancreatic islet cells by dithizone staining method, and pancreatic β-cells were further identified by both morphological features and electrophysiological characteristics, i.e. the existence of recording currents from KATP, Kv, and KCA. CONCLUSION： Islet cells differentiated from neonatal pancreatic duct cells with the new natural protocol are more advantageous in performing patch clamp study over the isolated adult pancreatic islet cells.

Effects of Iptakalim on intracellular free calcium concentration of cultured rabbit pulmonary arterial smooth muscle cells

Objective：To explore the effects of Iptakalim on intracellular free calcium concentration and on the proliferation of cultured rabbit pulmonary arterial smooth muscle cells induced by endothelin-1 （ET-1） in vitro. Methods：A cell culture model, [^3H]-thymidine（[^3H]-TdR） incorporation test and confocal microscope were used to observe proliferation and intracellular free calcium concentration（[Ca^2±]） of rabbit PASMC induced by ET-1 in vitro. Results：The value of [^3H]-TdR incorporation in ET-1 group was increased 1.468 times higher than that in control group. Iptakalim at the concentration of 10^-7mol/L, 10^-6mol/L ,10^-5 mol/L lowered [^3H]-TdR incorporation by （19.8 ± 4.6）%, （41.2 ± 9.5）%, （54.7 ± 10.1）%, respectively, compared with the value of the cells treated with ET-1（P〈 0.01）; The intracellular fluorescence intensity of PASMC in ET-1 group was increased from 73.70 ± 10.12 to 143.84 ± 28.23, significantly higher than that in control group（P 〈 0.01）; whereas with Iptakalim,the fluorescence intensity（FI） was only increased from 74.30 ± 10.20 to 86.03 ± 9.82, significantly lower than that in ET-1 group（P 〈 0.01）. Conclusion：Iptakalim inhibited proliferation of PASMC and decreased intracellular free calcium concentration of cultured rabbit PASMC induced by ET-1.

（non）Markovian process quantum fisher information quantum Cramer–Rao bound decoherence channels entangled states Heisenberg＇s limit phase sensitivity

In the present study, time evolution of quantum Cramer–Rao bound of entangled N00N state, as phase sensitivity, is determined by the aid of quantum estimation theory in the presence decoherence channels. Also, the dynamic quantum process as decoherence approach is characterized by quantum fisher information flow and entanglement amount in order to distinguish between Markovian and Non-Markovian process. The comparison between quantum fisher information and quantum fisher information flow assists to comprehend the phase sensitivity evolution corresponding to Non-Markovian and Markovian process. Furthermore, as result of backflow of information from the environment to system, the phase sensitivity corresponding memory effect of environment are revived after complete decay and increase in the few times.

ATP sensitive K^+ channel may be involved in the protective effects of preconditioning in isolated guinea pig cardiomyocytes

Objective To develop a cellular model of preconditioning by a brief period of hypoxia in isolated guinea pig cardiomyocytes and to determine whether or not an ATP sensitive K+ (KATP) channel is involved in ischemic preconditioning. Methods Single myocytes were isolated from the ventricle of adult guinea pigs. The experimental chamber allowed the cells to be exposed to low O2 pressure. During hypoxic preconditioning, the cells were equilibrated with normaxic solution for 10 minutes and then exposed to hypoxia for 5 minutes, followed by 10 minutes of reoxygenation. The cells were then subjected to 20-180 minutes of hypoxia and reoxygenation. Ionic currents were studied with the patch clamp technique in whole-cell and cell-attached configurations. Results A 5-minute hypoxic preconditioning offered a significant protection from cell injury in subsequent hypoxia-reoxygenation. After a latency of more than 15 minutes, hypoxia induced a time-independent outward K+ current which could be blocked by 5?μmol/L glibenclamide. At 10?mV, the current increased from 78±15?pA to 1581±153?pA (P<0.01, n=18). However, the latency to develop KATP channel currents (IKATP) was greatly shortened in preconditioned cells, and the current was increased acceleratively. At 10?mV, the current more than 4?nA was recorded in preconditioning cells. In the single channel recordings, the time interval from the first channel opening to maximum opening was also markedly abbreviated in preconditioned cells. Conclusion Isolated guinea pig cardiomyocytes can be preconditioned with a brief period of hypoxia. This hypoxic preconditioning may modify the KATP channel, and make the channel open more readily during the second hypoxia.

The ATP sensitive K^+ channel and membrane potential in the pathogenesis of vascular hyporeactivity in severe hemorrhagic shock

To elucidate the mechanism of vascular hyporeactivity following severe hemorrhagic shock (HS) by studying the changes of ATP sensitive potassium channels (K ATP ) properties and membrane potential of mesenteric arteriolar smooth muscle cells. Methods: Single channel currents were studied on cell attached and inside out patches of enzymatically isolated mesenteric arteriolar smooth muscle cells (ASMCs). Membrane potentials of arteriolar strips and ASMCs were recorded by intracellular membrane potential recording method and confocal microscopy, respectively. Results: K ATP channels in ASMCs were activated, which induced smooth muscle hyperpolarization following vascular hyporeactivity in HS. Conclusions: Hyperpolarizing effect of K ATP channel activation plays an important role in low vasoreactivity during severe hemorrhagic shock.

Myocardial protection with pinacidil induced hyperpolarized arrest during cardiopulmonary bypass

Objective To investigate the myocardial protective effects of pinacidil induced hyperpolarized arrest and compare with those afforded by conventional depolarized hyperkalemic arrestMethods Eighteen dogs were equally divided into three groups: normothermic hyperpolarized group (Group A), hypothermic hyperpolarized group (Group B), and hyperkalemic group (Group C) Pinacidil (50μmol/L) containing 37℃ St Thomas solution (K+5mmol/L, 10ml/kg), pinacidil (50μmol/L, Sigma, USA) containing 4℃ St Thomas solution (K+ 5mmol/L, 10ml/kg) and 4℃ standard St Thomas solution (K+ 16mmol/L, 10ml/kg) were infused respectively through the aortic root after aorticclamping Heart arrest and its recovery, ultrastructure of the myocardium, the level of serum myocardial enzymes, and lipid peroxide and adenine cleotide of the myocardium were measuredHemodynamics during ischemia and after reperfusion were observedResults The percentages of normal mitochondria and glycogen did not change much during ischemia (except at 60 min) and after reperfusion in B Group, but declined markedly in Group C 30 min and 60 min after ischemia and 20 min after reperfusion (P<0.01) In Group A,they were lower than those of Group B before ischemia, but higher than those of Group C The recoveries of CO, SV, CI, LVSW, RVSW and MAP in Group B were significantly better than those in other two groups 15 min and 30 min after reperfusion (P<0.05and0.01, respectively) However, they were still better in Group A than those in Group C(P<0.05 and 0.01, respectively)The onset of heart arrest was faster in Groups C and B than that in Group A Highly elevated serum myocardial enzymes were observed 60 min after ischemia and 20 min after reperfusion in Group C, while they were only mild in the hyperpolarized groups, especially in Group B, and their recoveries were rapid Adenine nucleotides of the myocardium were better preserved in Group B than in other two groups 30 min, 60 min after ischemia, and 20 min after reperfusion (P<0.05 and 0.01, respectively)They were also much better in Group A than in GroupC(P<0.05and0.01,respectively)Lipid peroxide of the myocardium were significantly lower in Group B than in other groups 20 min after reperfusion (P<0.01),and they were lower in Group A than in Group C(P<0.05) Conclusions Myocardial protection for global ischemia during cardiopulmonary bypass (CPB) could be achieved with hyperpolarized heart arrest induced by pinacidil, an ATP sensitive potassium channel opener,especially in the hypothermic state The protection is weaker in normothermia but is still superior to that with traditional depolarized hyperkalemic arrest

Anti-aging effects of chlorpropamide depend on mitochondrial complex-Ⅱ and the production of mitochondrial reactive oxygen species

Sulfonylureas are widely used oral anti-diabetic drugs.However,its long-term usage effects on patients’lifespan remain controversial,with no reports of influence on animal longevity.Hence,the anti-aging effects of chlorpropamide along with glimepiride,glibenclamide,and tolbutamide were studied with special emphasis on the interaction of chlorpropamide with mitochondrial ATP-sensitive K+(mito K-ATP)channels and mitochondrial complex II.Chlorpropamide delayed aging in Caenorhabditis elegans,human lung fibroblast MRC-5 cells and reduced doxorubicin-induced senescence in both MRC-5 cells and mice.In addition,the mitochondrial membrane potential and ATP levels were significantly increased in chlorpropamide-treated worms,which is consistent with the function of its reported targets,mito K-ATP channels.Increased levels of mitochondrial reactive oxygen species(mt ROS)were observed in chlorpropamide-treated worms.Moreover,the lifespan extension by chlorpropamide required complex II and increased mt ROS levels,indicating that chlorpropamide acts on complex II directly or indirectly via mito K-ATP to increase the production of mt ROS as a pro-longevity signal.This study provides mechanistic insight into the anti-aging effects of sulfonylureas in C.elegans.