Evidence for a neuronal release of isotopically labelled gamma-amino-n-butyric acid (GABA) from the rat dorsal medulla in vivo.

High potassium and electrical stimulation consistently increase efflux of labelled GABA from the in vivo superfused rat dorsal medulla in a calcium-dependent fashion. The depolarizing alkaloid, veratridine, also evokes a large increase in efflux of labelled GABA. These data strongly suggest release from a neurotransmitter pool in this region.