[在培养基中钙和钠含量不同时，角贝（Coretus corneus）软体动物A和B神经元的生物电特性]

[Bioelectric characteristics of A and B neurons in the mollusc Coretus corneus with different calcium and sodium contents in the medium].

作者信息

Sologub M I, El-Sayed E M

出版信息

Fiziol Zh SSSR Im I M Sechenova. 1975 May;61(5):690-8.

Abstract

Action potentials (AP) of neurons A and B could be only elicited in the presence of Na-+ ions. An increase in [Ca-++]0 led to depolarization of neurons, enhancement of their excitability, AP, overshoot, of positive afterpotential, AP duration, AP maximal rate of fall (Vf) and to decrease in AP maximal rate of rise (Vr). After addition of CaCl2 up to 50 mmoles into the Ringer solution, the membrane resistance (R) increased. If the [Na-+]0 was equimolarly diminished, R increased up to the [Ca-++]0 30 mmoles, but at greater [Ca-++]0 R fall below the initial value. The regularities were independent of the initial value of resting potential (RP). At high [Ca-++]0 Ca-++ contributed to the generation of the inward current during AP while Na-+ caused an increase in ionic (calcium) membrane permeability at rest. At high [Ca-++]0, Na-+ was also necessary for support of membrane channels which maintained the inward and outward currents during the AP.

摘要

神经元A和B的动作电位（AP）仅在存在Na⁺离子的情况下才能引发。细胞外Ca²⁺浓度（[Ca²⁺]₀）的增加导致神经元去极化，兴奋性增强，动作电位、超射、正后电位、动作电位持续时间、动作电位最大下降速率（Vf）增加，动作电位最大上升速率（Vr）降低。向林格溶液中加入高达50毫摩尔的CaCl₂后，膜电阻（R）增加。如果细胞外Na⁺浓度（[Na⁺]₀）等摩尔减少，R增加至[Ca²⁺]₀为30毫摩尔时，但在更高的[Ca²⁺]₀时，R降至初始值以下。这些规律与静息电位（RP）的初始值无关。在高[Ca²⁺]₀时，Ca²⁺在动作电位期间有助于内向电流的产生，而Na⁺在静息时导致离子（钙）膜通透性增加。在高[Ca²⁺]₀时，Na⁺对于维持动作电位期间内向和外向电流的膜通道的支持也是必需的。