Polymerase chain reaction analysis of ion channel expression in single neurons of brain slices

The study of gene expression and regulation in the central nervous system (CNS) is a daunting task because of the diversity of neuronal phenotypes and the complexity of many protein classes. Molecular cloning revealed the presence of a large number of different protein families in the CNS, each comprising several members. Ligand-gated ion channels may serve as an example to illustrate this point (for review, see Unwin, 1993). Heterologous expression combined with electrophysiological analysis suggests that ligand-gated channels are multimeric proteins with functional properties depending on the subunit composition. Very little is known, however, about how the functional properties of the recombinant and native receptors relate to each other. Thus, it is of eminent importance to elucidate the subunit expression profile in different types of neurons in the CNS and to correlate this with the functional properties of the native receptors.