Effects of GABA and glycine on sympathetic preganglionic neurons in the upper thoracic intermediolateral nucleus of the cat.

GABA (5-137 nA) and glycine (5-75 nA) each inhibit spontaneous activity and block antidromic invasion of the soma-dendritic region of single sympathetic preganglionic neurons (SPNs) in the intermediolateral nucleus of T1-T3 in the cat. These effects are rapid in onset and recovery. They are selectively blocked by bicuculline and strychnine respectively. Thus, GABA and glycine exert pharmacologically specific inhibitory effects on SPNs and this supports the possibility that they may be chemical mediators of inhibitory inputs directly onto these neurons.