Release of gamma-aminobutyric acid from the visual cortex of young kittens.

Barbiturate-anaesthetized kittens of less than one month of age were used for the quantitative determination of the in vivo release of endogenous gamma-aminobutyric acid (GABA) from visual cortex by two methods: push-pull perfusion and cortical cup superfusion. Analysis by high-performance liquid chromatography (HPLC) demonstrated that marked elevations of GABA were elicited during electrical stimulation of cortex (inside the cup or adjacent to the cannulae) and were released into the artificial extracellular fluid perfused within the collecting cup or through the cannulae. The results provide additional support for the view that GABA-mediated neuronal inhibition in early ontogenetic stages of visual cortex is widespread and robust.