激活视网膜水平细胞离子型谷氨酸受体抑制γ-氨基丁酸转运体电流(英文)

Suppression of γ-aminobutyric acid transporter current by activation of ionotropic glutamate receptors on retinal horizontal cells

本工作在酶解分离的鲫鱼视网膜水平细胞上研究了AMPA受体对γ-氨基丁酸(γ-aminobutyric acid,GABA)转运体电流的调节作用。由1mmol/L GABA所诱导的GABA转运体电流被持续50s的AMPA(30μmol/L或3mmol/L)预灌流所抑制。在细胞内液中施加10mmol/L BAPTA可以减弱AMPA对GABA转运体电流的抑制效应。施加3mmol/L AMPA+3mmol/ LNMDA所引起的抑制效应和单独施加3mmol/L AMPA或3mmol/L NMDA所引起的抑制效应相仿。以上结果表明,和激活NMDA受体调节GABA转运体的机制一样,激活视网膜水平细胞上的AMPA受体可以通过胞内钙过程来抑制GABA转运体电流。

In the present study, the modulatory effect of AMPA receptors on γ-aminobutyric acid （GABA） transporter current was investigated on enzymatically isolated horizontal cells of carp retina. The GABA transporter current elicited by 1 mmol/L GABA was decreased immediately after pre-application of AMPA （30/.tmol/L or 3 mmol/L） for 50 s. Application of 10 mmol/L BAPTA in intracellular solution inhibited the suppression effect of AMPA on GABA transporter current. The suppression effect induced by coapplication of 3 mmol/L AMPA and 3 mmol/L NMDA was similar to that of 3 mmol/L AMPA or 3 mmol/L NMDA alone. These results suggest that the activation of AMPA receptors inhibits GABA transporter-mediated current by affecting intracellular Ca^2＋ processes in the retinal horizontal cells, which is identical with the modulatory effect of NMDA receptors on GABA transporters.