Calcium-independent release of gamma-aminobutyrate from nerve processes in the developing rabbit retina.
Retinas from 3- and 10-day-old rabbits, and from young (29 days), or adult animals were used to study in parallel the development of synaptic vesicles in amacrine cells and the Ca2+ dependence of the K+-stimulated [3H]gamma-aminobutyrate release from them. Few synaptic vesicles were observed in the amacrine cell processes in retinas from the 3-day-old rabbits. The number of vesicles significantly increased between 3 and 10 days and increased further between day 10 and the adult animal. The Ca2+ dependence of the K+-stimulated release decreased with increasing age. There is thus a poor correlation between the Ca2+ dependent transmitter release and the number of synaptic vesicles in the nerve terminal, favouring the existence of a Ca2+ dependent nonvesicular process for the [3H]gamma-aminobutyrate release in the rabbit retina.
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D009474:Neurons / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D011188:Potassium / Q000494:pharmacology; D011817:Rabbits; D012160:Retina / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism* / Q000502:physiology
D005680:gamma-Aminobutyric Acid; D011188:Potassium; D002118:Calcium