Characterization of the analgesic properties of nomifensine in rats.
The analgesic properties of the catecholamine uptake inhibitor nomifensine were investigated in the tail immersion, hot plate and formalin tests. Systemic administration of nomifensine produced analgesia only in the formalin test. The analgesia was dose-dependent (0.625-5 mg/kg), and the highest dose completely abolished nociceptive behaviors induced by 2% formalin. The analgesia was not affected by the opioid antagonist naltrexone (2.5-40 microg s.c.) but was dose-dependently reversed by the D2 antagonist eticlopride (181.3-270 microg/kg i.p.). Neither naltrexone nor eticlopride affected formalin pain scores. Nomifensine analgesia appears to be dopamine-mediated but independent of opioid mechanisms.
Gilbert
A K
AK
Department of Psychology, McGill University, Montreal, Quebec, Canada.
Franklin
K B
KB
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009271:Naltrexone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009627:Nomifensine / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D000700:Analgesics; D018765:Dopamine Uptake Inhibitors; D009292:Narcotic Antagonists; D009627:Nomifensine; D009271:Naltrexone