Effects of some amino acids on horizontal cells in the fish retina.
Effects of some amino acids on horizontal cells were examined in the fish (Eugerres plumieri) retina. L-aspartate (5 mM in concentration) and L-glutamate (10 mM) consistently depolarized all types of horizontal cells, although the effect of L-aspartate was more pronounced. gamma-Aminobutyric acid (GABA; 10 mM) consistently hyperpolarized the cone-connected L- and C-type horizontal cells, whereas the effect on the rod-connected cells was slight or nonexistent. The hyperpolarizing effect of GABA on the cone-horizontal cells was markedly diminished by picrotoxin (0.1 mM). Usually, glycine (10 mM) showed slight and variable effects. It merely depolarized some cone-horizontal cells but weakly hyperpolarized some rod-horizontal cells. In a few cases, however, glycine began to drastically hyperpolarize the cone-horizontal cells in retinas that had been repeatedly treated with certain agents used. Taurine and beta-alanine (10 mM each) had negligible effects, although the former slightly depolarized and the latter merely hyperpolarized both cone- and rod-horizontal cells.
D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D005399:Fishes / Q000502:physiology*; D005971:Glutamates / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D010786:Photoreceptor Cells / Q000187:drug effects*; D010852:Picrotoxin / Q000494:pharmacology; D012160:Retina / Q000187:drug effects*; D013654:Taurine / Q000494:pharmacology; D015091:beta-Alanine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D000596:Amino Acids; D001224:Aspartic Acid; D005971:Glutamates; D005998:Glycine; D010852:Picrotoxin; D013654:Taurine; D015091:beta-Alanine; D005680:gamma-Aminobutyric Acid