RESUMO
The dopamine (DA) pathway mediates numerous neuronal functions which are implicated in psychiatric disorders. Previously, our lab investigated the status of the dopamine transporter in the Wistar-Kyoto rat, a purported rodent model of depressive behavior, and reported significant alterations in transporter binding sites in several brain regions when compared to control rat strains. Given that DA-2 and DA-3 receptors belong to the same class of DA receptors, are co-localized in the mesolimbic and nigrostriatal regions of the brain and function as autoreceptors, this study mapped the distribution of central DA-2 and DA-3 receptors in Wistar-Kyoto and Wistar rats. The results indicated that while the binding of 125I-sulpride to DA-2 receptors was higher in the nucleus accumbens (shell) and ventral tegmental area, it was lower in the nucleus accumbens (core), caudate putamen and hypothalamus in Wistar-Kyoto compared to Wistar rats. In contrast, the binding of 125I-sulpride to DA-3 receptors was higher in the caudate putamen, nucleus accumbens (shell and core) and islands of Calleja in Wistar-Kyoto compared to Wistar rats. Given that DA-2 like receptors in the ventral tegmental area function as autoreceptors, it is possible that the greater inhibitory effects exerted by DA-2 and DA-3 receptors in Wistar-Kyoto rats may lead to a net deficit in DA levels in areas receiving projection from this cell body area.
