突触体中氨基酸释放的突触前调制。

Presynaptic modulation of amino acid release from synaptosomes.

作者信息

Sherman A D, Hegwood T S, Baruah S, Waziri R

机构信息

Department of Psychiatry, College of Medicine, University of Iowa, Iowa City 52242.

出版信息

Neurochem Res. 1992 Feb;17(2):125-8. doi: 10.1007/BF00966789.

DOI:10.1007/BF00966789

PMID:1371602

Abstract

Using synaptosomes prepared from whole rat brain, the spontaneous, calcium-independent, and calcium-dependent release of glutamate and GABA was assessed. Time intervals of 1-30 seconds were studied. Spontaneous release of glutamate (but not GABA) was elevated by 10 microM NMDA or AMPA by thirty seconds. This stimulation was partially calcium-dependent. Calcium-dependent release induced by 30 mM KCl was biphasic, confirming previous findings. This release was stimulated at all time periods by the presence of 10 microM NMDA or AMPA in an antagonist-sensitive manner. These data suggest that glutamate and GABA are released from vesicular stores in rat synaptosomes and that some of this release is modulated by presynaptic glutamate receptors.

摘要

利用从大鼠全脑中制备的突触体，评估了谷氨酸和γ-氨基丁酸（GABA）的自发性、非钙依赖性和钙依赖性释放。研究了1至30秒的时间间隔。10微摩尔的N-甲基-D-天冬氨酸（NMDA）或α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）可使谷氨酸（而非GABA）的自发性释放在30秒时升高。这种刺激部分依赖于钙。30毫摩尔氯化钾诱导的钙依赖性释放是双相的，证实了先前的研究结果。在所有时间段，10微摩尔的NMDA或AMPA以拮抗剂敏感的方式刺激这种释放。这些数据表明，谷氨酸和GABA从大鼠突触体的囊泡储存中释放，并且这种释放的一部分受到突触前谷氨酸受体的调节。