[神经营养物质对钾离子去极化过程中脑突触体释放γ-氨基丁酸的作用]

[Action of neurotropic substances on gamma-aminobutyric acid release from brain synaptosomes during K+ depolarization].

作者信息

Maĭsov N I, Nikushkin E V, Kryzhanovskiĭ G N

出版信息

Biull Eksp Biol Med. 1985 Apr;99(4):451-3.

Abstract

The effects of aminazine (0.25 mM), phthoracyzine (0.5 mM), trifluperidole (0.5 mM) and imipramine (0.5 mM) on GABA release from rat brain synaptosomes depolarized with K+ (50 mM) were investigated. Incubation of synaptosomes with aminazine led to a 2-fold and that with phthoracyzine, trifluperidole and imipramine to a 1.5-fold increase in GABA release from synaptosomes as compared with its basic level. The raising of K+ in the incubation medium to 50 mM brought about a 2-fold augmentation of GABA release. Exposure of synaptosomes to drugs and a higher K+ concentration at a time did not change GABA release as compared to its basic level. Introduction into the incubation medium of the Ga-ionophore A23187 together with 50 mM K+ and trifluperidole or with K+ and imipramine led to the same increase in GABA release from synaptosomes as that produced by the psychotropic drugs as regards native synaptosomes. It is assumed that the lack of the influence of the psychotropic drugs under study of GABA release from synaptosomes depolarized with K+ is caused by blockade of synaptic membrane conductibility for Ca2+.

摘要

研究了氯丙嗪（0.25 mM）、奋乃静（0.5 mM）、三氟哌多（0.5 mM）和丙咪嗪（0.5 mM）对用50 mM K⁺ 使其去极化的大鼠脑突触体释放γ-氨基丁酸（GABA）的影响。与突触体基础水平相比，用氯丙嗪孵育突触体导致GABA释放增加2倍，用奋乃静、三氟哌多和丙咪嗪孵育则导致GABA释放增加1.5倍。将孵育培养基中的K⁺ 浓度提高到50 mM可使GABA释放增加2倍。与基础水平相比，突触体同时暴露于药物和较高K⁺ 浓度下时，GABA释放没有变化。将Ga离子载体A23187与50 mM K⁺ 和三氟哌多或与K⁺ 和丙咪嗪一起加入孵育培养基中，对于天然突触体而言，导致突触体释放的GABA增加幅度与精神药物产生的幅度相同。据推测，所研究的精神药物对用K⁺ 使其去极化的突触体释放GABA缺乏影响是由于突触膜对Ca²⁺ 的传导性被阻断所致。