DIFFERENTIAL EXPRESSION OF GABA TRANSPORTER-1 MESSENGER-RNA IN SUBPOPULATIONS OF GABA NEURONS

Using in situ hybridisation with an oligonucleotide probe, the regiona l distribution of GABA transporter-1 messenger RNA was determined in t he adult rat CNS. Overall, the distribution of GABA transporter-1 mRNA was similar to that of glutamate decarboxylase-67 mRNA, consistent wi th an expression in GABA neurones. However, in cerebellar cortex, Purk inje cells which express high levels of glutamate decarboxylase-67 mRN A did not express GABA transporter-1 mRNA, whereas Bergmann glia expre ssed GABA transporter-1 mRNA at high levels. In some other brain regio ns, including the inferior colliculus and reticular thalamus, there wa s no GABA transporter-1, although there were neurones which expressed glutamate decarboxylase-67 messenger RNA at high levels.