The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaes:hesia ( or awake) animals. This technique can be used to study the...The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaes:hesia ( or awake) animals. This technique can be used to study the synaptic function and plasticity in central nervous system in vivoin order to understand the physiological properties of the ion channels from an integrated point of view. The advantage of this technique have already presented itself in the study of the synaptic transmission and nervous network. Nowadays, in vivo patch whole-cell recording technique in combination with other techniques is becoming a common method in the research fields.展开更多
Using the whole cell patch clamp technique, the effect of Cu^2+on transient outward K^+current (/to) and delayed rectifier K^+ current (Idr) was studied in acutely isolated rat hippocampal neurons.Ito and Idr w...Using the whole cell patch clamp technique, the effect of Cu^2+on transient outward K^+current (/to) and delayed rectifier K^+ current (Idr) was studied in acutely isolated rat hippocampal neurons.Ito and Idr were increased when the concentration of Cu^2+ was lower than 2 × 10^-5 and 10^-5 tool/L, respectively, and increased ratio was decreased with increasing Cu^2+concentration in the bath solutions. When the concentration continued to increase to 5× 10^-5 and 2 × 10^- 5 mol/L, the currents were hardly changed, while the concentration was more than 10^-4 and 5 × 10^-5 mol/L, the currents were inhibited remarkably. Cu^2+ (10^-5 mol/L) did not affect the activation and inactivation process of Ito. The activation curve of Idr was shifted toward positive potential, but 10^-5 mol/L Cu^2+did not affect slope factor. According to these results, it was considered that Cu^2+at low concentration in the bath solution could promote Ito and Idr while at high concentration could inhibit them, and change of amplitude was different with different membrane voltage. Conclusion was drawn: Cu^2+may be involved in the pathophysiologic mechanism of diseases with neuropathological components.展开更多
The current difference between male and female rabbit ventricular myocytes was investigated for elucidating the mechanism of longer QT interval and higher incidence of drug-associated torsade de pointes in female rabb...The current difference between male and female rabbit ventricular myocytes was investigated for elucidating the mechanism of longer QT interval and higher incidence of drug-associated torsade de pointes in female rabbits than in male rabbits. Whole cell patch clamp technique was used to record APD, I_to, I_K,tail, I_K1 and I_Ca,L of myocytes from left ventricular apex. There was no difference in the membrane capacitance between male and female rabbit myocytes. APD_90 was longer in female rabbits (560.4±26.5 ms, n=15) than in male ones (489.0±20.7 ms, n=14), P<0.05. In female rabbit myocytes, I_K,tail, I_to, I_K1 and I_Ca,L were 0.71±0.05 pA/pF (n=17), 8.28±1.03 pA/pF (n=18), 24.5±3.6 pA/pF (n=12) and 9.0±2.3 pA/pF (n=15) respectively. In male rabbit myocytes, they were 0.84±0.07 pA/pF (n=18), 8.60±1.20 pA/pF (n=18), 25.9±4.5 pA/pF (n=14) and 9.3±2.6 pA/pF (n=16) respectively. I_K,tail in female rabbits was significantly lower than that of male rabbits (P<0.05), but there was no difference in I_to, I_K1 and I_Ca,L between male rabbits and female rabbits (P>0.05). The lower I_K,tail of female rabbit myocytes may contribute to the longer repolarization and the higher incidence of drug-associated torsade de pointes.展开更多
In this study, the effects of acute SO_2 derivatives and chronic lead exposure together on sodium cur-rents (INa) were investigated in acutely isolated rat hippocampal neurons by using the whole-cell patch clamp techn...In this study, the effects of acute SO_2 derivatives and chronic lead exposure together on sodium cur-rents (INa) were investigated in acutely isolated rat hippocampal neurons by using the whole-cell patch clamp techniques. We found that chronic lead exposure hardly reduced the amplitudes of INa. In the normal condition, sodium current started to appear at around ?70 mV, and reached the peak current at around ?40 mV. After chronic lead exposure, the data changed to ?70 and ?30 mV. After adding SO2 derivatives, the data changed to ?80 and ?40 mV, respectively. SO_2 derivatives caused a significant in-crease of INa in hippocampal chronic-lead exposed neurons. Chronic lead exposure induced a right shift of the activation curve and a left shift of the inactivation curve of sodium channels. SO_2 derivatives caused negative shifts of the activation and inactivation curves of INa in hippocampal chronic-lead ex-posed neurons. Lead exposure put off the time reaching the peak of INa activation. SO_2 derivatives in-creased the time constants of inactivation after lead exposure. The interaction of lead and SO_2 deriva-tives with voltage-dependent sodium channels may lead to changes in electrical activity and contribute to worsening the neurotoxicological damage.展开更多
The effects of La^3+ on proliferation, cell cycles, apoptosis and ion channels were investigated in mouse embryo fibroblast NIH 3T3 cells and its possible mechanisms were explored. Our data showed that La^3+ promote...The effects of La^3+ on proliferation, cell cycles, apoptosis and ion channels were investigated in mouse embryo fibroblast NIH 3T3 cells and its possible mechanisms were explored. Our data showed that La^3+ promoted cell proliferation with increased S-phase entry and inhibited the outward potassium currents in a concentration-dependent manner in NIH 3T3 cells. La^3+ and Ca^2+ had synergistic effect on cell proliferation and cell cycles. It showed that Ca^2+ was needed for La^3+ promoted cell cycle progression. Using the whole-cell voltage-clamp technique, we found that La^3+ blocked the outward potassium current in a Lanthanum ions can increase intracellular Ca^2+ concentration concentration-dependent manner in NIH 3T3 cells. through inhibition of potassium currents, which induce a series of physiological changes and improve proliferation of cells. This may be one of the molecular mechanisms of lanthanum ions induced cell proliferation. The present work provides a new perspective for understanding the biological and toxicological effects of lanthanum.展开更多
Background Long QT syndrome(LQTS)is a potentially fatal cardiac ion channel disease.Mutations in the gene encoding cardiac hERG potassium channel are the second most common causes of LQTS.Cardiac hERG potassium channe...Background Long QT syndrome(LQTS)is a potentially fatal cardiac ion channel disease.Mutations in the gene encoding cardiac hERG potassium channel are the second most common causes of LQTS.Cardiac hERG potassium channel conducts the rapidly activating delayed rectifier potassium current(Ikr),which is one of the crucial currents in rapid repolarization phase of action potential in human cardiomyocytes.Function of hERG potassium channel is regulated by a variety of signaling pathways,in which phosphorylation and dephosphorylation of tyrosine proteins plays a major role.Previous research has found that non-receptor protein tyrosine phosphatase(PTPN)can interact with hERG potassium channel in cardiac cells.The aims of the present study were to investigate the regulatory effect of protein tyrosine phosphatase non-receptor type 12,11 and 6(PTPN12,PTPN11 and PTPN6)on cardiac hERG potassium channels.Methods HEK-293 cells were transfected with pcDNA3.0-hERG by Lipofectamine 2000 and selected by G418.HEK-293/hERG cells stably expressing hERG protein were then transfected with pcDNA3.1-PTPN12-RFP,pcDNA3.1-PTPN11-EGFP and pcDNA3.1-PTPN6-EGFP,respectively.Forty-eight hours after transfection,immunofluorescence assay and western blot were performed to detect the expression of hERG channel proteins and PTPN proteins.hERG channel currents in hERG alone-expressing group,PTPN12-,PTPN11-and PTPN6-overexpressing groups,as well as inhibitor groups were recorded by patch clamp technique.Results The maximum pulse current densities of PTPN12-,PTPN11-and PTPN6-overexpressing groups were all decreased when compared with hERG alone-expressing group(P<0.05).However,the maximum pulse current densities of inhibitor groups were all increased when compared with PTPN12-,PTPN11-and PTPN6-overexpressing groups,respectively(P<0.05).Conclusions Overexpression of PTPN12,PTPN11 and PTPN6 reduced the current density of hERG potassium channel,while this effect could be reversed by tyrosine phosphatase inhibitors.These results suggested that PTPN12,PTPN11 and PTPN6 negatively regulated hERG potassium channel currents by catalyzing the dephosphorylation process of hERG potassium channels.[S Chin J Cardiol 2021;22(1):38-49]展开更多
Objectives The effects of carvedilol on sodium current (INa) were investigated in isolated adult rat ventricular myocytes. Methods Single ventricular myocytes were enzymatically dissociated. INa was recorded by whol...Objectives The effects of carvedilol on sodium current (INa) were investigated in isolated adult rat ventricular myocytes. Methods Single ventricular myocytes were enzymatically dissociated. INa was recorded by whole-cell patch- clamp recording technique. Results an IC50of (6. 35 - 0.40) mol . L^- 1. Carvedilol reversibly inhibited INa in a concentration-dependent manner, with 2. This inhibition was voltage- and frequency-dependent. 3. Carvedilol decreased the peak of the I-V relationship curve at -35 mV from (17.31± 1.68) pA/pF to (6. 58 ± 1.35) pA/pF, but did not change active potential, peak potential and the reverse potential significantly. 4. The steady-state inactivation curve of INa was shifted to more negative potentials. Conclusions Carvedilol inhibits INa in adult rat ventricular myocytes by mechanisms involving preferential interaction with the inactivated state of sodium channel.展开更多
文摘The patch clamp recording technique in vivois a blind patch clamp recording methods to record the current of the spinal or cereral neurons of anaes:hesia ( or awake) animals. This technique can be used to study the synaptic function and plasticity in central nervous system in vivoin order to understand the physiological properties of the ion channels from an integrated point of view. The advantage of this technique have already presented itself in the study of the synaptic transmission and nervous network. Nowadays, in vivo patch whole-cell recording technique in combination with other techniques is becoming a common method in the research fields.
基金Project supported by the National Natural Science Foundation of China (No. 30470408).
文摘Using the whole cell patch clamp technique, the effect of Cu^2+on transient outward K^+current (/to) and delayed rectifier K^+ current (Idr) was studied in acutely isolated rat hippocampal neurons.Ito and Idr were increased when the concentration of Cu^2+ was lower than 2 × 10^-5 and 10^-5 tool/L, respectively, and increased ratio was decreased with increasing Cu^2+concentration in the bath solutions. When the concentration continued to increase to 5× 10^-5 and 2 × 10^- 5 mol/L, the currents were hardly changed, while the concentration was more than 10^-4 and 5 × 10^-5 mol/L, the currents were inhibited remarkably. Cu^2+ (10^-5 mol/L) did not affect the activation and inactivation process of Ito. The activation curve of Idr was shifted toward positive potential, but 10^-5 mol/L Cu^2+did not affect slope factor. According to these results, it was considered that Cu^2+at low concentration in the bath solution could promote Ito and Idr while at high concentration could inhibit them, and change of amplitude was different with different membrane voltage. Conclusion was drawn: Cu^2+may be involved in the pathophysiologic mechanism of diseases with neuropathological components.
文摘The current difference between male and female rabbit ventricular myocytes was investigated for elucidating the mechanism of longer QT interval and higher incidence of drug-associated torsade de pointes in female rabbits than in male rabbits. Whole cell patch clamp technique was used to record APD, I_to, I_K,tail, I_K1 and I_Ca,L of myocytes from left ventricular apex. There was no difference in the membrane capacitance between male and female rabbit myocytes. APD_90 was longer in female rabbits (560.4±26.5 ms, n=15) than in male ones (489.0±20.7 ms, n=14), P<0.05. In female rabbit myocytes, I_K,tail, I_to, I_K1 and I_Ca,L were 0.71±0.05 pA/pF (n=17), 8.28±1.03 pA/pF (n=18), 24.5±3.6 pA/pF (n=12) and 9.0±2.3 pA/pF (n=15) respectively. In male rabbit myocytes, they were 0.84±0.07 pA/pF (n=18), 8.60±1.20 pA/pF (n=18), 25.9±4.5 pA/pF (n=14) and 9.3±2.6 pA/pF (n=16) respectively. I_K,tail in female rabbits was significantly lower than that of male rabbits (P<0.05), but there was no difference in I_to, I_K1 and I_Ca,L between male rabbits and female rabbits (P>0.05). The lower I_K,tail of female rabbit myocytes may contribute to the longer repolarization and the higher incidence of drug-associated torsade de pointes.
基金the National Natural Science Foundation of China(Grant No.20637010)University of Science and Technology Foundation of Shanxi Prov-ince(Grant No.200713010)
文摘In this study, the effects of acute SO_2 derivatives and chronic lead exposure together on sodium cur-rents (INa) were investigated in acutely isolated rat hippocampal neurons by using the whole-cell patch clamp techniques. We found that chronic lead exposure hardly reduced the amplitudes of INa. In the normal condition, sodium current started to appear at around ?70 mV, and reached the peak current at around ?40 mV. After chronic lead exposure, the data changed to ?70 and ?30 mV. After adding SO2 derivatives, the data changed to ?80 and ?40 mV, respectively. SO_2 derivatives caused a significant in-crease of INa in hippocampal chronic-lead exposed neurons. Chronic lead exposure induced a right shift of the activation curve and a left shift of the inactivation curve of sodium channels. SO_2 derivatives caused negative shifts of the activation and inactivation curves of INa in hippocampal chronic-lead ex-posed neurons. Lead exposure put off the time reaching the peak of INa activation. SO_2 derivatives in-creased the time constants of inactivation after lead exposure. The interaction of lead and SO_2 deriva-tives with voltage-dependent sodium channels may lead to changes in electrical activity and contribute to worsening the neurotoxicological damage.
基金Project supported by the National Natural Science Foundation of China (Nos. 20637010, 41072265), Shanxi Provincial Natural Science Foundation for Youth (No. 2007021010) and the Doctoral Scientific Research Foundation of Taiyuan University of Science and Technology (No. 20102027).
文摘The effects of La^3+ on proliferation, cell cycles, apoptosis and ion channels were investigated in mouse embryo fibroblast NIH 3T3 cells and its possible mechanisms were explored. Our data showed that La^3+ promoted cell proliferation with increased S-phase entry and inhibited the outward potassium currents in a concentration-dependent manner in NIH 3T3 cells. La^3+ and Ca^2+ had synergistic effect on cell proliferation and cell cycles. It showed that Ca^2+ was needed for La^3+ promoted cell cycle progression. Using the whole-cell voltage-clamp technique, we found that La^3+ blocked the outward potassium current in a Lanthanum ions can increase intracellular Ca^2+ concentration concentration-dependent manner in NIH 3T3 cells. through inhibition of potassium currents, which induce a series of physiological changes and improve proliferation of cells. This may be one of the molecular mechanisms of lanthanum ions induced cell proliferation. The present work provides a new perspective for understanding the biological and toxicological effects of lanthanum.
基金supported by the Key Project of Natural Science Foundation of Guangdong Province of China(No.2017B030311010)Science and Technology Program of Guangzhou,China(No.202002030088)
文摘Background Long QT syndrome(LQTS)is a potentially fatal cardiac ion channel disease.Mutations in the gene encoding cardiac hERG potassium channel are the second most common causes of LQTS.Cardiac hERG potassium channel conducts the rapidly activating delayed rectifier potassium current(Ikr),which is one of the crucial currents in rapid repolarization phase of action potential in human cardiomyocytes.Function of hERG potassium channel is regulated by a variety of signaling pathways,in which phosphorylation and dephosphorylation of tyrosine proteins plays a major role.Previous research has found that non-receptor protein tyrosine phosphatase(PTPN)can interact with hERG potassium channel in cardiac cells.The aims of the present study were to investigate the regulatory effect of protein tyrosine phosphatase non-receptor type 12,11 and 6(PTPN12,PTPN11 and PTPN6)on cardiac hERG potassium channels.Methods HEK-293 cells were transfected with pcDNA3.0-hERG by Lipofectamine 2000 and selected by G418.HEK-293/hERG cells stably expressing hERG protein were then transfected with pcDNA3.1-PTPN12-RFP,pcDNA3.1-PTPN11-EGFP and pcDNA3.1-PTPN6-EGFP,respectively.Forty-eight hours after transfection,immunofluorescence assay and western blot were performed to detect the expression of hERG channel proteins and PTPN proteins.hERG channel currents in hERG alone-expressing group,PTPN12-,PTPN11-and PTPN6-overexpressing groups,as well as inhibitor groups were recorded by patch clamp technique.Results The maximum pulse current densities of PTPN12-,PTPN11-and PTPN6-overexpressing groups were all decreased when compared with hERG alone-expressing group(P<0.05).However,the maximum pulse current densities of inhibitor groups were all increased when compared with PTPN12-,PTPN11-and PTPN6-overexpressing groups,respectively(P<0.05).Conclusions Overexpression of PTPN12,PTPN11 and PTPN6 reduced the current density of hERG potassium channel,while this effect could be reversed by tyrosine phosphatase inhibitors.These results suggested that PTPN12,PTPN11 and PTPN6 negatively regulated hERG potassium channel currents by catalyzing the dephosphorylation process of hERG potassium channels.[S Chin J Cardiol 2021;22(1):38-49]
基金supported by Guangdong Provincial Chinese Traditional Medicine Administration Foundation(2060033)Guangdong Provincial Medical Science and Technology Foundation (A2006002)
文摘Objectives The effects of carvedilol on sodium current (INa) were investigated in isolated adult rat ventricular myocytes. Methods Single ventricular myocytes were enzymatically dissociated. INa was recorded by whole-cell patch- clamp recording technique. Results an IC50of (6. 35 - 0.40) mol . L^- 1. Carvedilol reversibly inhibited INa in a concentration-dependent manner, with 2. This inhibition was voltage- and frequency-dependent. 3. Carvedilol decreased the peak of the I-V relationship curve at -35 mV from (17.31± 1.68) pA/pF to (6. 58 ± 1.35) pA/pF, but did not change active potential, peak potential and the reverse potential significantly. 4. The steady-state inactivation curve of INa was shifted to more negative potentials. Conclusions Carvedilol inhibits INa in adult rat ventricular myocytes by mechanisms involving preferential interaction with the inactivated state of sodium channel.