Section 11
Chapter 10,543

Effects of D1 and D2 dopamine receptor antagonists on cocaine-induced self-stimulation and locomotor activity in rats

Kita, K.; Shiratani, T.; Takenouchi, K.; Fukuzako, H.; Takigawa, M.

European Neuropsychopharmacology the Journal of the European College of Neuropsychopharmacology 9(1-2): 1-7


ISSN/ISBN: 0924-977X
PMID: 10082221
DOI: 10.1016/s0924-977x(97)00098-9
Accession: 010542017

To clarify the involvement of D1 and D2 dopamine systems in intracranial self-stimulation (ICSS) and locomotor activity in rats, we studied the acute effects of cocaine and the interaction between cocaine and dopamine antagonists with respect to these behaviors. Although cocaine (5.0, 10.0, or 20.0 mg/kg) dose-dependently increased locomotor activity, it augmented the rate of ICSS only at 5.0 mg/kg. The failure of high doses of cocaine to augment purpose-oriented behavior such as ICSS may result from its induction of a manic-like state. The D1 dopamine receptor antagonist SCH23390 (0.02, 0.1, or 0.5 mg/kg) or the D2 antagonist nemonapride (0.04, 0.2, or 1.0 mg/kg) significantly decreased cocaine augmentation of ICSS. The higher two doses of either antagonist also produced a significant decrease in cocaine-induced locomotor activity. We therefore suspect that cocaine's augmentative effect on those behaviors, especially ICSS, requires activation of both D1 and D2 dopamine receptors.

PDF emailed within 0-6 h: $19.90