Differential expression of GABA transporter-1 messenger RNA in subpopulations of GABA neurones.

Using in situ hybridisation with an oligonucleotide probe, the regional distribution of GABA transporter-1 messenger RNA was determined in the adult rat CNS. Overall, the distribution of GABA transporter-1 mRNA was similar to that of glutamate decarboxylase-67 mRNA, consistent with an expression in GABA neurones. However, in cerebellar cortex, Purkinje cells which express high levels of glutamate decarboxylase-67 mRNA did not express GABA transporter-1 mRNA, whereas Bergmann glia expressed GABA transporter-1 mRNA at high levels. In some other brain regions, including the inferior colliculus and reticular thalamus, there was no GABA transporter-1, although there were neurones which expressed glutamate decarboxylase-67 messenger RNA at high levels.