GABA-like activity in in vitro slices of the rat visual cortex: immunocytochemistry and electrophysiology

Using antisera raised against gamma-aminobutyric acid (GABA), GABA-like immunoreactivity was determined in in vitro slices fixed after various incubation times. Synaptic efficacy of GABAergic innervation was concurrently assessed in adjacent slices by intracellular recordings. We show that GABA-like immunoreactivity dramatically decreases already after one hour of incubation and remains low throughout the following hours. Nevertheless robust GABA-mediated synaptic potentials are recordable for more than 8 h.