Non-dopaminergic fibres may regulate dopamine-sensitive adenylate cyclase in the prefrontal cortex and nucleus accumbens.

Abstract

The dopaminergic (DA) innervation of the prefrontal cortex in rat originates from neurones distributed in the anterior medial part of the ventral tegmental area (VTA)1. Biochemical2,3 and electrophysiological4 studies have demonstrated that these mesocortico-prefrontal neurones are distinct from others located in the VTA which project to subcortical structures such as the nucleus accumbens. DA receptors coupled to an adenylate cyclase (D-1 receptors) are present in the prefrontal cortex and their topographical distribution closely resembles that of DA nerve terminals5–7. We have now further analysed the properties of the cortical D-1 receptors and compared them with those of a subcortical limbic structure examining, in the rat, the effects on DA-sensitive adenylate cyclase activity in the prefrontal cortex and the nucleus accumbens of (1) bilateral 6-hydroxydopamine (6-OHDA) microinjections in the VTA and (2) bilateral electrolytic lesions of the VTA. The results suggest that regulation of D-1 receptors is not solely dependent on the presynaptic DA innervation and that other non-DA fibres may contribute to it.