Suppression of gamma-aminobutyric acid transporter current by activation of ionotropic glutamate receptors on retinal horizontal cells.
In the present study, the modulatory effect of AMPA receptors on gamma-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 mumol/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 co-application 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.
Jiang
Xiao-Dong
XD
School of Life Sciences and Biotechnology, Shanghai Jiaotong University, China.
Sun
Yan
Y
Wang
Xu-Long
XL
Gong
Hai-Qing
HQ
Liang
Pei-Ji
PJ
D000818:Animals; D002347:Carps; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D050485:GABA Plasma Membrane Transport Proteins / Q000378:metabolism*; D058468:Receptors, Ionotropic Glutamate / Q000378:metabolism*; D051248:Retinal Horizontal Cells / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D050485:GABA Plasma Membrane Transport Proteins; D058468:Receptors, Ionotropic Glutamate; D004533:Egtazic Acid; D005680:gamma-Aminobutyric Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid