Role of dopamine D1 and D2 receptors in the nucleus accumbens in jaw movements of rats: a critical role of the shell

Abstract

Given the differences in the dopamine neurotransmission between the shell and the core of the nucleus accumbens, as well as the differential involvement of these two domains in oral behaviour of rats, it was decided to determine whether or not dopamine Dj and/or dopamine D 2 receptors differentially direct oral behaviour in these two domains in rats. Intra-accumbens injections of the dopamine D, receptor agonist ( + )-6-chloro-7,S-dihydroxy-3-alIyl-1 -phenyl-2,3,4,5-letrahydro-l/7-3-benzazepine (SKF 82958: 5 jiig/0.2 /¿I), the dopamine D2 receptor agonist quinpirole (10 ju,g/0.2 ¡j. 1) and their combination were used to assess the role of these accumbens domains in jaw movements of rats. The present study shows that the combined administration of SKF 82958 and quinpirole into the shell, but not the core, of the nucleus accumbens produced a highly significant increase in jaw movements, when doses which per se were nearly ineffective, were injected. This effect was fully inhibited by prior administra tion of either the dopamine D [ receptor antagonist 7M + )-7-chloro-8-hydroxy-3-methyl-l-phenyl-2,3,4,5-tetrahydro-l //-3-benzazepine (SCH 23390: 0.5 ¿¿g/0.2 ¡M g) or the dopamine D 2 receptor antagonist (-)-sulpiride (25 ng/0.5 /xl) into the same region. It is concluded that dopamine D, and D 2 receptors in the shell, but not the core, of the nucleus accumbens are involved in jaw movements of the rat, providing the first piece of evidence that dopamine Dj and D 2 receptors in the shell of the nucleus accumbens mediate a particular behaviour.

A Neurobehavioral Systems Analysis of Adult Rats Exposed to Methylazoxymethanol Acetate on E17: Implications for the Neuropathology of Schizophrenia

“…The present results are consistent with findings that MAM-E15 exposed offspring show higher susceptibility for chronic haloperidol-induced orofacial dyskinesias (Johansson 1990). Given that the striatal retogions innervated by the frontal cortex (i.e., medial and ventral striatum) mediate oral dyskinesias (Cools et al 1995;Hamid et al 1998;Prinssen et al 1996), the more potent effect of PCP on oral movements in the MAM-E17 animals is consistent with a hypo-function of the glutamatergic frontal corticostriatal pathway (Tamminga 1998). …”

Decreased choline acetyltransferase immunoreactivity in discrete striatal subregions following chronic haloperidol in rats

“…As mentioned above, the ventrolateral striatum has been identified as a region particularly important in the production of oral movements (Delfs and Kelley, 1990;Kelley et al, 1988;ScheelKruger and Arnt, 1985). The novel finding of a similar magnitude of decreased labeling in the accumbens is also of relevance, as studies have shown enhanced oral movements after pharmacological stimulation of the nucleus accumbens (Koene et al, 1993;Cools et al, 1995). Interestingly, examination of accumbal tissue from individuals treated for years with neuroleptics showed a decrease in ChAT activity (Bird et al, 1977).…”

Role of Dopamine D1and D2Receptors in the Nucleus Accumbens in Mediating Reward

“…In the ACB, synergistic effects of D 1 and D 2 agonists have been reported for locomotor activity (Dreher and Jackson, 1989;Essman et al, 1993;Koshikawa et al, 1996a), jaw movements (Cools et al, 1995;Koshikawa et al, 1996b), and neuronal firing (White, 1987). However, there is no clear information whether the interaction of D 1 and D 2 receptors within the ACB can produce a cooperative or synergistic effect on reinforcement processes.…”