高外淋巴钾和铷水平调节离体青蛙迷路中的感觉静息放电。

High perilymphatic potassium and rubidium levels modulate the sensory resting discharge in the isolated frog labyrinth.

作者信息

Rossi M L, Martini M

机构信息

Istituto di Fisiologia Generale, Università di Ferrara, Italy.

出版信息

Neurosci Lett. 1988 Oct 31;93(1):44-8. doi: 10.1016/0304-3940(88)90010-9.

DOI:10.1016/0304-3940(88)90010-9

PMID:3264896

Abstract

The effects of high perilymphatic K+ and Rb+ concentrations (20 mM) on the posterior canal resting discharge have been examined in the isolated frog labyrinth. Both K+ and Rb+ produced an increase in spike frequency which is sustained by a parallel increase in the excitatory postsynaptic potential (EPSP) emission rate. High K+ and Rb+ levels reduce the size of the afferent spike, broaden its time course but do not induce repetitive activity at the axon level. The K+ and Rb+ facilitation proved to be inversely related to the fibre's initial resting activity. The facilitation produced by increased K+ was usually larger than that in Rb+ solution. High sensitive and low sensitive units with similar low resting discharge were detected in relation to their response either to K+ or Rb+. The effects of both ions can be explained on the basis of their interactions with the presynaptic hair cell currents.

摘要

在离体青蛙迷路中，研究了高外淋巴钾离子（K⁺）和铷离子（Rb⁺）浓度（20 mM）对后半规管静息放电的影响。K⁺和Rb⁺均使动作电位频率增加，这是由兴奋性突触后电位（EPSP）发放率的平行增加所维持的。高K⁺和Rb⁺水平会减小传入动作电位的幅度，使其时程变宽，但不会在轴突水平诱发重复活动。K⁺和Rb⁺的易化作用被证明与纤维的初始静息活动呈负相关。K⁺增加所产生的易化作用通常大于在Rb⁺溶液中的易化作用。根据对K⁺或Rb⁺的反应，检测到具有相似低静息放电的高敏和低敏单位。两种离子的作用都可以基于它们与突触前毛细胞电流的相互作用来解释。