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本研究采用羊心脏浦肯野纤维标本,按其静息膜电位水平分为两组:;≥-75mV的为正常组,-40～-55mV为部分除极组。在降低细胞内外Na~+跨膜梯度的情况下,用细胞内离子选择电极监测细胞内Na~+主动逐出速率以测量细胞膜钠泵活动。结果表明,除极组细胞内Na~+活度(a~1Na)对照值及在预先提高细胞内Na~+水平的情况下所测得的Na~+逐出速半与正常组无显著差别。因而认为,自然部分除极的浦肯野纤维膜钠泵机能并无不可逆转的损伤。其除极原因可能主要与膜对K~+的通透性降低有关。
In this study, Purkinje fiber samples of sheep heart were divided into two groups according to their resting membrane potential: ≥-75mV for normal group and -40 ~ -55mV for partial depolarization group. In the case of decreasing the Na + transmembrane gradient inside and outside the cell, the intracellular Na ~ + active evacuation rate was monitored by the intracellular ion-selective electrode to measure the membrane sodium pump activity. The results showed that Na ~ + activity (a ~ 1Na) in control group and Na ~ + excretion half speed in the pretreatment of intracellular Na ~ + did not show significant difference . Therefore, that part of the natural part of Purkinje fiber membrane sodium pump function is not irreversible damage. The reasons for its depolarization may be mainly related to the membrane permeability of K ~ + decreased.