Modulation of GABAc response by Ca2+ and other divalent cations in horizontal cells of the catfish retina

The influence of extracellular calcium ions and other divalent metal ions on the activity of the gamma amino butyric acid receptor c (GABAc) of the horizontal cells of the catfish retina was evaluated using patch clamp analysis. Results indicate that calcium has an excitatory effect while zinc has an inhibitory effect on GABAc responses. The implications of these findings on the regulation of events in the horizontal cells are discussed.