Dopaminergic effects on tail-flick response in spinal rats.
R-Apomorphine (0.02-1.75 mumol/kg), administered by intrathecal infusion to spinalized rats, caused a dose-dependent increase in tail-flick latency. The effect of R-apomorphine was counteracted significantly by the dopaminergic receptors antagonists cis-flupenthixol (0.20-3.94 mumol/kg) and (+)-butaclamol (0.78 mumol/kg), but not by their enantiomers nor by phenoxybenzamine (29.40 mumol/kg) or methysergide (29.40 mumol/kg). The findings suggest that dopaminergic mechanisms play a role in the modulation of nociception in the spinal cord.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D004347:Drug Interactions; D008297:Male; D009619:Nociceptors / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology*; D011954:Receptors, Dopamine / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*
D011954:Receptors, Dopamine; D001058:Apomorphine