Ochi R
Pflugers Arch. 1982 Sep;394(3):250-5. doi: 10.1007/BF00589100.
The membrane constants of guinea-pig papillary muscle have been derived by cable analysis, utilizing a single sucrose gap and micro-electrode recordings. In Na-free 20 mmol/l Sr Tyrode, the longitudinal resistance (ri) was increased by 210% from the control value after the passage of ten action potentials (APs) and by 457% after twenty APs but this increase in ri was reversibly abolished by perfusing with Na-containing solutions. ri was not affected by stimulation in Na-containing 20 mmol/l Sr Tyrode. Concomitant with the increase in ri, the conduction velocity of Sr APs was decreased from the control level of 8.6 to 3.1 cm/s after about twenty evoked Sr APs. The twitches elicited in the Na-free Sr Tyrode were large but the relaxation time was comparatively slow (20-30s), whereas those elicited in the Na-containing Sr Tyrode had a large amplitude and relaxation occurred within a few seconds. It is suggested that the increase in ri is due to junctional decoupling, produced either directly, by an intracellular accumulation of Sr2+, or indirectly by an increase in intracellular H+.
利用单蔗糖间隙和微电极记录，通过电缆分析得出了豚鼠乳头肌的膜常数。在无钠的20 mmol/L Sr Tyrode溶液中，经过10次动作电位（AP）后，纵向电阻（ri）较对照值增加了210%，经过20次AP后增加了457%，但通过用含钠溶液灌注，ri的这种增加可被可逆地消除。在含20 mmol/L Sr的Tyrode含钠溶液中进行刺激，ri不受影响。随着ri的增加，在约20次诱发的Sr AP后，Sr AP的传导速度从对照水平的8.6 cm/s降至3.1 cm/s。在无钠的Sr Tyrode溶液中引发的抽搐幅度大，但松弛时间相对较慢（20 - 30秒），而在含钠的Sr Tyrode溶液中引发的抽搐幅度大且在几秒内发生松弛。提示ri的增加是由于连接解偶联，这是由Sr2+的细胞内积累直接产生，或由细胞内H+增加间接产生的。
