EFFECTS OF GABA, GLYCINE, PICROTOXIN AND BICUCULLINE METHOCHLORIDE ON RUBROSPINAL NEURONS IN CATS

A microelectrophoretic study was performed of the actions of GABA and glycine, and of their antagonists on rubrospinal neurons. GABA and glycine depressed antidromic and synaptic potentials, hyperpolarized the cell membrane and increased the membrane conductance. GABA was more effective than glycine. Corticorubral IPSP [inhibitory post synaptic potentials] and the GABA-induced membrane hyperpolarization could be reversed by intracellular application of hyperpolarizing currents. Picrotoxin and bicuculline methochloride antagonized inhibitory GABA actions and the corticorubral IPSP or the corresponding extracellular positive field potential. GABA is apparently the transmitter of the corticorubral inhibition in the cat.