Modulation of a 40-kDa catecholamine-regulated protein following d-amphetamine treatment in discrete brain regions

A 40-kDa catecholamine-regulated protein (CRP40) has been demonstrated to be expressed in the central nervous system, and is known to bind to dopamine and related catecholamines. Recently, it has been shown that dopamine D1 receptor antagonist and dopamine D2 receptor antagonist differentially modulated the CRP40 protein in the striatum. In the present study, we examined the effects of the indirect psychostimulant, D-amphetamine, on (CRP40) expression in discrete brain regions. The technique of Western immunoblotting was utilized for quantitation of CRP40 in different experimental paradigms following D-amphetamine treatment. Acute treatment with D-amphetamine (5.0 mg/kg, i.p.) caused no significant change in CRP40 levels in either of the two brain regions studied: striatum and nucleus accumbens. Chronic D-amphetamine administration (2.5 mg/kg, i.p.) significantly increased CRP40 levels in striatum and nucleus accumbens (37.64 +/- 14.57% and 27.86 +/- 8.40%, respectively, P < or = 0.05). Chronic and possibly sensitized D-amphetamine challenged rats (0.5 mg/kg, i.p.) showed a significant increase in CRP40 levels in the nucleus accumbens only (40.49 +/- 15.91%, P < or = 0.05). Although CRP40 has a consensus motif with the 70-kDa heat shock protein (HSP70), levels of HSP70 remained unchanged under identical experimental conditions. The results of this study demonstrate selective modulation of CRP40 by D-amphetamine treatment, without affecting the 70-kDa heat shock protein.