Distribution of GABA(B(1a)), GABA(B(1b)) and GABA(B2) receptor protein in cerebral cortex and thalamus of adult rats

The distribution of GABA(B) receptor subunits GABA(B(1a)), GABA(B(1b)) and GABA(B2), has been examined in the cerebral cortex and thalamus of adult ra ts using an immunocytochemical technique. GABA(B(1a)) and GABA(B(1b)) subun its co-localized with GABA(B2) in the cortex, where afferent thalamic GABAe rgic axons project to pyramidal neurones. The expression patterns of GABA(B (1a)), GABA(B(1b)) and GABA(B2) were similar throughout the thalamus. The d ata suggest that the GABA(B(1b)) subunit might be the presynaptic isoform i n the thalamo-cortical pathway with the GABA(B(1a)) subunit possibly presen t at postsynaptic sites on cell bodies. This contrasts with our previous da ta, obtained in cerebellum and spinal cord which indicate opposite location s. Thus, it seems unlikely that functional role along with cellular locatio n can be assigned in a general manner to specific GABAB receptor subunit sp lice variants. NeuroReport 12:591-595 (C) 2001 Lippincott Williams & Wilkin s.