Interactions between enkephalin and gamma-aminobutyric acid in the larval tiger salamander retina.
Both double-label and intracellular electrophysiological recording techniques were utilized to investigate the interactions between enkephalin and gamma-aminobutyric acid in the larval tiger salamander retina. Double-label studies revealed that the vast majority (greater than 96%) of enkephalin-immunostained amacrine cells also exhibit high affinity uptake of [3H]gamma-aminobutyric acid. Electrophysiological evidence demonstrated that morphine and gamma-aminobutyric acid exert opposite effects on a population of On-Off ganglion cells. gamma-Aminobutyric acid decreased the activity of these cells, while enkephalin increased their activity. These findings support the idea that opiate-mediated pathways inhibit GABAergic pathways in the vertebrate retina.
D000818:Animals; D004745:Enkephalins / Q000378:metabolism*; D007814:Larva / Q000502:physiology; D008564:Membrane Potentials; D009020:Morphine / Q000494:pharmacology; D012160:Retina / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology; D014562:Caudata / Q000378:metabolism / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000502:physiology
D004745:Enkephalins; D005680:gamma-Aminobutyric Acid; D009020:Morphine