MOLECULAR NEUROBIOLOGY OF THE GABA(A) RECEPTOR

This chapter discusses the molecular neurobiology of the GABAA receptor. The GABAA receptor is responsible for the majority of neuronal inhibition in the vertebrate CNS. The ubiquitous distribution of the GABAA receptor in the mammalian CNS is revealed by the use of [3H]GABA radioligand binding techniques, whereas autoradiographic studies have demonstrated their distinct topographical localization. There is evidence that the receptor is not only expressed in regions of the cell that receive GABAergic input, but also, for example, on Golgi cell somata where no synaptic contacts are found. With the two monoclonal antibodies used in this study, no immunoreactivity is detected on axons, nerve terminals, or glial cells. The distribution of the GABAA receptor at both synaptic and nonsynaptic sites is quite distinct from that of the closely associated glycine receptor, which appears to be mainly associated with synapses. Initial electrophysiological studies of the GABAA receptor demonstrated that its activation by GABA resulted in an increased chloride conductance of the supporting neuronal membrane. © 1994 Academic Press Inc.