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 authors used suspension cells of Populus euphratica to isolate protoplast in the present study. Protoplasts were successfully obtained after 4 hours incubation in enzyme solution containing 1 0% cellulase “o...The authors used suspension cells of Populus euphratica to isolate protoplast in the present study. Protoplasts were successfully obtained after 4 hours incubation in enzyme solution containing 1 0% cellulase “onozuka” R\|10, 0\^01% pectolyase Y\|23,0\^15% macerozyme R\|10 and 0\^1% hemicellulase at 25℃. Outward and inward single channels in plasma membrane were observed using cell\|attached recording of patch\|clamp technique. In this study, single channel records showed that more than one species of channel were obtained. These attempts in protoplast isolation and ion channel recording offers the opportunity to characterize cellular mechanisms of salt tolerance in tree species.展开更多
目的研究大蒜素对HEK293细胞HERG电流的作用,探讨其抗心律失常的可能机制。方法采用瞬时转染的方法,将HERG通道质粒转入HEK293细胞上,应用细胞外局部灌流法于膜片钳高阻抗封接形成后给予大蒜素,使其终浓度为30μmol/L。室温下,采用全细...目的研究大蒜素对HEK293细胞HERG电流的作用,探讨其抗心律失常的可能机制。方法采用瞬时转染的方法,将HERG通道质粒转入HEK293细胞上,应用细胞外局部灌流法于膜片钳高阻抗封接形成后给予大蒜素,使其终浓度为30μmol/L。室温下,采用全细胞膜片钳技术在电压钳形模式下记录电流和门控动力学,观察大蒜素对HERG电流的作用。结果 30μmol/L大蒜素对正常大鼠心室肌细胞HERG电流有显著的阻滞效应,使其尾电流密度由73.5±4.3 p A/p F降低至42.1±3.6 p A/p F(P<0.01,n=14)。其作用呈浓度依赖性。半数抑制浓度为34.74μmol/L,Hill系数为1.01。大蒜素可使HERG的电流-电压曲线降低,且随着去极化电位的增加,作用更加明显,提示其作用具有电压依赖性,门控机制研究发现大蒜素可以使通道激活曲线向更正的方向移动,进而延迟激活;使通道稳态失活更负的方向移动,导致失活加速。同时,使通道灭活的慢时间常数缩短,从而加速通道的灭活。结论大蒜素抑制HEK293细胞上HERG电流,提示这可能是其治疗心律失常的细胞电生理基础。展开更多
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 authors used suspension cells of Populus euphratica to isolate protoplast in the present study. Protoplasts were successfully obtained after 4 hours incubation in enzyme solution containing 1 0% cellulase “onozuka” R\|10, 0\^01% pectolyase Y\|23,0\^15% macerozyme R\|10 and 0\^1% hemicellulase at 25℃. Outward and inward single channels in plasma membrane were observed using cell\|attached recording of patch\|clamp technique. In this study, single channel records showed that more than one species of channel were obtained. These attempts in protoplast isolation and ion channel recording offers the opportunity to characterize cellular mechanisms of salt tolerance in tree species.
基金This work was supported by grants from the Wellcome Trust UK (056909/299/Z) the Ministry of Education China (GJ9901) the Health Department of Guangdong Province (A2001474).
基金This work was supported by the National Natural Science Foundation of China (No. 39370270)the Natural Science Foundation of Educational Department of Sichuan Province (No. 2003A058).
文摘目的研究大蒜素对HEK293细胞HERG电流的作用,探讨其抗心律失常的可能机制。方法采用瞬时转染的方法,将HERG通道质粒转入HEK293细胞上,应用细胞外局部灌流法于膜片钳高阻抗封接形成后给予大蒜素,使其终浓度为30μmol/L。室温下,采用全细胞膜片钳技术在电压钳形模式下记录电流和门控动力学,观察大蒜素对HERG电流的作用。结果 30μmol/L大蒜素对正常大鼠心室肌细胞HERG电流有显著的阻滞效应,使其尾电流密度由73.5±4.3 p A/p F降低至42.1±3.6 p A/p F(P<0.01,n=14)。其作用呈浓度依赖性。半数抑制浓度为34.74μmol/L,Hill系数为1.01。大蒜素可使HERG的电流-电压曲线降低,且随着去极化电位的增加,作用更加明显,提示其作用具有电压依赖性,门控机制研究发现大蒜素可以使通道激活曲线向更正的方向移动,进而延迟激活;使通道稳态失活更负的方向移动,导致失活加速。同时,使通道灭活的慢时间常数缩短,从而加速通道的灭活。结论大蒜素抑制HEK293细胞上HERG电流,提示这可能是其治疗心律失常的细胞电生理基础。
