The antidepressive-like effect of oxcarbazepine: possible role of dopaminergic neurotransmission

It has been previously shown that oxcarbazepine (OXCBZ), a keto-analogue of carbamazepine, exhibits an antidepressive-like effect profile in the learn ed helplessness and forced swimming test (FST). Since carbamazepine possess es dopaminergic effect, the present study was carried out to evaluate the e xtent to which the antidepressive effect of OXCBZ might be mediated by dopa minergic system. Thus, the effects of OXCBZ in haloperidol-induced cataleps y and apomorphine-induced stereotypy were studied. The anti-immobility effe ct of OXCBZ in the FST was also evaluated in haloperidol pretreated rats. O XCBZ (40 and 80 mg/kg, i.p.) dose-dependently reduced the catalepsy induced by haloperidol (2.0 mg/kg, i.p.). Moreover, OXCBZ (80 mg/kg, but not 20 or 40 mg/kg, i.p.) increased the intensity of apomorphine-induced stereotypy (0.6 mg/kg, s.c.). Finally, it was observed that the combination of OXCBZ ( 80 mg/kg, i.p.) and haloperidol (0.5 mg/kg, i.p.) antagonized the anti-immo bility effect of OXCBZ and further increased the immobility time when compa red to haloperidol alone. Haloperidol alone (0.5 or 1.0 mg/kg) did not chan ge the immobility time. Thus, these results suggest that OXCBZ could enhanc e dopaminergic neurotransmission, which might mediate its antidepressive-li ke effect. (C) 2000 Elsevier Science B.V. All rights reserved.