Role of dopamine D sub(1) and D sub(2) receptors in the nucleus accumbens in mediating reward

• Published in: The Journal of neuroscience 1997-11, Vol.17 (21), p.8580-8587
• Main Authors: Ikemoto, S, Glazier, B S, Murphy, J M, McBride, W J
• Format: Article
• Language: English
• ISSN: 0270-6474

The objectives of this study were to examine the involvement of D sub(1) and D sub(2) receptors within the nucleus accumbens (ACB) in mediating reinforcement. The intracranial self-administration (ICSA) of D sub(1) and D sub(2) agonists was used to determine whether activating D sub(1) and /or D sub(2) receptors within the ACB of Wistar rats is reinforcing. At concentrations of 0.25, 0.50, and 1.0 mM (25, 50, and 100 pmol/100 nl of infusion), neither the D sub(1) agonist R(+)-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine-7,8-diol [SKF 38393 (SKF)] hydrochloride nor the D sub(2) agonist (-)-quinpirole (Quin) hydrochloride was self-administered into the shell region of the ACB. On the other hand, equimolar mixtures of SKF and Quin (SKF+Quin), at concentrations of 0.25, 0.50, and 1.0 mM each, were significantly self-infused into the ACB shell. The core region of the ACB did not support the ICSA of SKF+Quin at any of these concentrations. Rats increased lever pressing when the response requirement was increased from a fixed ratio 1 (FR1) to FR3, and they responded significantly more on the infusion lever than they did on the control lever. Coadministration of either 0.50 mM R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3- b enzazepine (SCH 23390) hydrochloride, a D sub(1) antagonist, or 0.50 mM S(-)-sulpiride, a D sub(2) antagonist, completely abolished the ICSA of the mixture of SKF+Quin (each at 0.50 mM) into the ACB shell. The present results suggest that concurrent activation of D sub(1)- and D sub(2)-type receptors in the shell of the ACB had a cooperative effect on DA-mediated reward processes.