细胞内钠离子在培养的海马细胞中对突触传递和囊泡池更新的调节作用。

A role of intracellular Na+ in the regulation of synaptic transmission and turnover of the vesicular pool in cultured hippocampal cells.

作者信息

Bouron A, Reuter H

机构信息

Department of Pharmacology, University of Bern, Switzerland.

出版信息

Neuron. 1996 Nov;17(5):969-78. doi: 10.1016/s0896-6273(00)80227-5.

DOI:10.1016/s0896-6273(00)80227-5

PMID:8938128

Abstract

Propagation of action potentials in axons and dendrites increases intracellular Na+ ([Na+]i) and Ca2+ concentrations ([Ca2+]i). While the importance of [Ca2+]i in synaptic transmission is well established, a possible functional role of [Na+]i is unclear. In cultured hippocampal cells, [Na+]i was increased by veratridine. We have then measured spontaneous excitatory postsynaptic currents (sEPSCs) and, by means of fluorescent dyes, changes in [Na+]i, in [Ca2+]i, and in the turnover of the vesicular pool of individual boutons. An elevation of [Na+]i and a concomitant rise in [Ca2+]i, led to a large increase in sEPSC frequency and in the turnover of the presynaptic vesicular pool. Extracellular Ca2+ was essential for these effects of elevated [Na+]i on synaptic transmission. They probably occur via Na+/Ca2+ exchange.

摘要

动作电位在轴突和树突中的传播会增加细胞内钠离子（[Na⁺]i）和钙离子浓度（[Ca²⁺]i）。虽然[Ca²⁺]i在突触传递中的重要性已得到充分证实，但[Na⁺]i可能的功能作用尚不清楚。在培养的海马细胞中，藜芦碱可使[Na⁺]i升高。然后我们测量了自发兴奋性突触后电流（sEPSCs），并通过荧光染料测量了[Na⁺]i、[Ca²⁺]i的变化以及单个突触小体囊泡池的周转情况。[Na⁺]i的升高以及随之而来的[Ca²⁺]i的升高，导致sEPSC频率和突触前囊泡池周转大幅增加。细胞外钙离子对于[Na⁺]i升高对突触传递的这些作用至关重要。它们可能通过钠/钙交换发生。