SEMI-QUANTITATIVE single cell RT-PCR techniques were used to determine the expression of mRNAs related to GABAergic and cholinergic neurotransmission in neurons of the rat globus pallidus and adjacent basal forebrain region. Neurons of the globus pallidus expressed relatively high levels of GAD67 and GABA vesicular transporter mRNA but undetectable levels of ChAT or ACh vesicular transporter mRNA. In contrast, nominally basal forebrain neurons co-expressed ChAT and GAD67 mRNAs and mRNAs for both ACh and GABA vesicular transporters. These results suggest that the neurons along the medial border of the globus pallidus may co-release GABA and ACh.