Involvement of dopamine D₂ and 5-HT_1A receptors in roxindole-induced antinociception

Abstract

Roxindole, a DA D₂ receptor aganist (2-16 mg/kg) produced dose-dependent increase in percentage antinociception. The effect which was blocked by DA D₂ antagonist (-)sulpiride (50 mg/kg) and 5-HT_1A receptor antagonist (-) pin dolol (5 mg/kg). Roxindole (4 and 8 mg/kg) reversed both naloxone (20 mg/kg)-induced hyperalgesia and reserpine (2 mg/kg)-induced hyperalgesia. This reversal was sensitive to blockade by both (-)sulpiride (50 mg/kg) and (-) pindolol (5mg/kg). The present study suggests that roxindole-induced antinociception is mediated by postsynaptic DA D₂ and 5-HT_1A receptors.