Gesztelyi I, Kónya L, Kövér A
Acta Physiol Acad Sci Hung. 1980;55(1):1-11.
The effect of primycin, a guanidine-type antibiotic was studied on the electric properties and 42K+ uptake of the frog sartorius and semitendinosus muscle. Both in normal and choline chloride Ringer solution, primycin evoked a concentration and time dependent depolarization of the surface membrane of the muscle. This depolarization was significantly increased by Na ions. Primycin treatment was shown to evoke a dose-dependent decrease of the depolarization induced by 20 mM K+-Ringer. When the muscles were incubated in a Ringer solution containing choline chloride, during an incubation period of 30 min the uptake of 42K+ was decreased to 12% upon the exposure to 5 x 10(-6) mol primycin as compared to the control value. As the primycin-induced depolarization increased, the shape and amplitude of the action potentials elicited by square-wave electric impulses were altered and decreased, respectively. In sodium isaethionate Ringer 1--2 x 10(-6) M primycin induced a slow depolarization resulting in firing potentials. The results suggest that primycin depolarizes the surface membrane exclusively through the blockade of the resting K+ channels, the other phenomena being the results of this depolarizing effect.
研究了胍类抗生素原霉素对青蛙缝匠肌和半腱肌电特性及42K+摄取的影响。在正常和氯化胆碱林格溶液中，原霉素均能引起肌肉表面膜浓度和时间依赖性的去极化。钠离子可显著增强这种去极化。结果表明，原霉素处理可引起20 mM K+-林格溶液诱导的去极化呈剂量依赖性降低。当肌肉在含有氯化胆碱的林格溶液中孵育时，在30分钟的孵育期内，与对照值相比，暴露于5×10(-6) mol原霉素后，42K+的摄取量降至12%。随着原霉素诱导的去极化增加，方波电脉冲引发的动作电位的形状和幅度分别发生改变并减小。在羟乙磺酸钠林格溶液中，1--2×10(-6) M原霉素诱导缓慢去极化，导致发放电位。结果表明，原霉素仅通过阻断静息K+通道使表面膜去极化，其他现象是这种去极化作用的结果。
