Characterization of putative amino acid transmitter release from slices of rat dentate gyrus.

摘要: — Superfused slices of the rat dentate gyrus were employed to study release GABA, glutamate and aspartate, which are considered strong neurotransmitter candidates in this region. The introduction Ca2+ a Ca2+-free superfusion medium containing depolarizing agent augmented efflux all three amino acids. response application nearly always occurred within 30 s, shortest interval tested these studies. rate reached peak 90 s then declined level slightly greater than prestimulation baseline. failure maintain maximal with continued exposure influences appeared not result from reduction permeability caused by continuous depolarization. also stimulated exogenously loaded radiolabeled but proline. Exogenously GABA was more readily released endogenous GABA. Otherwise effects various treatments on their rates qualitatively similar. Mg2+ inhibited Ca2+-dependent efflux. Ba2+, Mg2+, acid absence Ca2+. Extracellular Na+ required support Addition slices, or aspartate. K+-enriched alkaloid, veratridine, both Ca2+-independent processes. Na+-free enhanced releasing action elevated K+. raising Mg2+ concentration 15 mM be as well. Amino output is probably directly related transmission partially general increase membrane induced depolarization stimulation carrier-mediated efflux. These results previously suggested transmitter roles for aspartate gyrus.