ANTI-NOCICEPTIVE EFFECT OF RESERPINE AND HALOPERIDOL MEDIATED BY THE NIGRO-STRIATAL SYSTEM - ANTAGONISM BY NALOXONE

Reserpine (10 mg/kg) and haloperidol (2 mg/kg) injected intraperitoneally increased the reaction time of the tail-flick response in intact but not in pre-nigrally decerebrate or spinal rats. The anti-nociceptive effect of both drugs was antagonized by intraperitoneal injections of dopa (100 mg/kg), apomorphine (2mg/kg) or naloxone (1 mg/kg) as well as by bilateral micro-injections into the caudate nuclei of apomorphine (100 μg and 20 μg) and naloxone (10 μg). It is concluded that the nigrostriatal feedback system is involved in the anti-nociceptive effect of reserpine and haloperidol. © 1979 Springer-Verlag.