RESTING K-CONDUCTANCES IN PACEMAKER AND NON-PACEMAKER HEART-CELLS OF THE RABBIT
RESTING K-CONDUCTANCES IN PACEMAKER AND NON-PACEMAKER HEART-CELLS OF THE RABBIT
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DOI：
10.2170/jjphysiol.34.245
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发表时间：
1984-01-01
期刊：
影响因子：
--
通讯作者：
IRISAWA, H
中科院分区：
文献类型：
--
作者：
NOMA, A;NAKAYAMA, T;IRISAWA, H
通过内向整流器K通道的电流。**图表**。和乙酰胆碱操作的K通道。**图形**。用膜片钳技术，电极尖端内径为0.5-1微米，记录于兔离体心细胞。打开的最大重叠数。**图形**。在347次实验中测量了每个贴片的通道。室性细胞平均2.3个，窦房(S-A)和房室结(A-V)细胞0.0 3~0.0 6个。**图形**的估计总数。每个心室细胞的通道足够大，以提供细胞的静息K电导。**图形**。通道存在于S-A和房室结细胞中，而在心室细胞中未见。用全细胞钳记录测得的结节细胞的静息电导约为心室细胞静息电导的16倍，且几乎不受镀液中K+的影响。结节细胞的膜电位低于心室细胞的原因是静息膜的K电导较小，这是由于**图形**的密度很低所致。频道。**图形**。当被神经调节激活时，通道可能在结节细胞产生静息K电导中起主要作用。
Currents through the inward rectifier K channel .**GRAPHIC**. and the ACh[acetylcholine]-operated K channel .**GRAPHIC**. were recorded in isolated heart cells of rabbit using the patch clamp technique with electrodes having 0.5-1 .mu.m tip inner diameter. The maximum number of overlaps of open .**GRAPHIC**. channels per patch was measured over 347 experiments. An average of 2.3 was found in ventricular cells and 0.03-0.06 in sinoatrial (S-A) and atrioventricular (A-V) node cells. The estimated total number of the .**GRAPHIC**. channels for each ventricular cell was great enough to supply the resting K conductance of the cell. The .**GRAPHIC**. channel was present in S-A and A-V node cells, but was never observed in the ventricular cells. The resting conductance of the nodal cells measured with whole cell clamp recordings was about 16 times smaller than that of the ventricular cells and was hardly decreased at all by the removal of K+ from the bath solution. The lower membrane potential of the nodal cells compared with that of the ventricular cells was attributed to the smaller K conductance of the resting membrane, which is due to the very low density of the .**GRAPHIC**. channel. The .**GRAPHIC**. channel, when activated by neural regulation, may play a major role in generating the resting K conductance of the nodal cells.