Effects of dopamine on gamma-amino-butyric acid-activated currents in neutron of visual cortex of rat / 中华实验眼科杂志

ABSTRACT

Background As a main suppressing neurotransmitter in visual system,gamma-aminobutyric acid (GABA) participates in the transmission and regulation of visual information.GABA and dopamine (DA) coexist in the visual cortex,and their mutual effects should be clarified.Objective This study was to investigate the effect of DA on GABA-activated current in vitro in cultured visual cortical neurons of rats.Methods Neutrons from visual cortex of clean neonatal rats were isolated and cultured by explant culture method.The neutrons cultured for 11 -to 14- days were collected for the record of whole cell currents of GABA-A (IGABA) channels in vitro using patch clamp technique.The DA solution (100mmol/L),SKF38393 (10mmol/L) solution and quinpirole solution(10mmol/L) were prepared with double distilled water and then the extracellular fluid was added to different concentrations.The IGABA changing rate under the action of SKF38393+SCH23390,SKF38393+Quinpirole for different time was recorded respectively and compared with that of action of DA,SKF38393,SCH23390,Quinpirole.The IGABA activated by extracellular fluid along served as control.Results The IGABA was significantly attenuated after activated by ≥10μmol/L of DA or SKF38393 separately in comparison to that of extracellular fluid action (P＜0.05).In various time of action,there were obviously differences in IGABA between DA or SKF38393 action and extracellular fluid (P＜0.05,P＜0.01).No evident change in IGABA changing rate was found after only SCH23390 action in comparison with extracellular cells (P＜0.05).However,after combination of SCH23390 and SKF38393,IGABA changing rate reduced by 19.49%.No significant differences were found in the changing rates of IGABA among different concentrations of quinpirole action groups compared with extracellular fluid group (P＞0.05);while when quinpirole was combined with SKF38393,the IGABA was elevated in comparison with only SKF38393 action group (P＜0.05).Conclusion Dopamine participates in the transfer and regulation of visual information through suppressing GABA-activated currents from neutrons of visual cortex at time-dependent manner in vitro.