Differential modulation of a 40 kDa catecholamine regulated protein in the core and shell subcompartments of the nucleus accumbens following chronic quinpirole and haloperidol administration in the rat

Past reports have shown dopamine (DA) D2/D3 receptor agonist quinpirole (QNP) and the DA D2 receptor antagonist, haloperidol (HAL) display a significant increase in expression of catecholamine regulated protein (CRP40) in the nucleus accumbens (NAcc) and the striatum, respectively. The present study investigated the in vivo effects of QNP and HAL on CRP40 protein levels within the core and shell subcompartments of the NAcc. As significant homology exists between CRP40 and Hsp70/Hsc70, parallel studies with inducible Hsp70 and constitutive Hsc70 were conducted to establish the specificity with respect to QNP on Hsp70 and CRP40. Results demonstrated that CRP40 protein was significantly expressed in the shell relative to the core region of NAcc following chronic QNP (+16.28%+/-0.42%, P<0.05) and CRP40 protein was significantly expressed in the core vs. the shell following chronic HAL (+36.02%+/-0.75%, P<0.05). There was no significant change in Hsp70 protein levels following chronic QNP or HAL administration. The results demonstrated selective modulation of CRP40 within NAcc by QNP and HAL treatment, without affecting Hsp70.