GABA receptor binding in rat cerebral cortex and superior cervical ganglion in the absence of GABAergic synapses

High affinity binding of [ 3H]γ-aminobutyric acid (GABA) to membrane-containing homogenates prepared from rat cerebral cortex (neonatal or adult) or from adult rat superior cervical ganglion (SCG) was tested for sensitivity to baclofen, bicuculline and several other analogues of GABA. Since no major differences were found between the tissues free of GABAergic synapses (SCG and neonatal cortex) and GABAergic synapse-rich adult rat cortex, it is suggested that the presence of GABAergic synapses does not play a decisive role in the determination of pharmacological sensitivities of high-affinity GABA receptors.