Antinociceptive effect of systemic kelatorphan, in mononeuropathic rats, involves different opioid receptor types.
The antinociceptive effect of i.v. kelatorphan (2.5, 5, 10 and 15 mg/kg), a mixed inhibitor of enkephalin degrading enzymes, was studied in a rat model of peripheral unilateral mononeuropathy (chronic constriction of the common sciatic nerve). Kelatorphan at 2.5 and 5 mg/kg had no significant effect on the vocalization threshold to paw pressure test, but higher doses (10 mg/kg) produced a significant antinociceptive effect which plateaued at 15 mg/kg, on both hindpaws. Kelatorphan (10 mg/kg) was co-injected with the specific mu-, delta- and kappa-opioid receptor antagonists naloxone (0.1 mg/kg), naltrindole (1 mg/kg) or nor-binaltorphimine (1 mg/kg). The effect of kelatorphan 10 mg/kg was completely prevented by naloxone, reduced by 75% by naltrindole (both hindpaws), and reduced by 50% by nor-binaltorphimine (contralateral paw only).
Lee
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SH
Unité de Recherches de Physiopharmacologie du Système Nerveux, INSERM U 161, Paris, France.
Kayser
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Guilbaud
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D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D004151:Dipeptides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004195:Disease Models, Animal; D008297:Male; D009619:Nociceptors / Q000187:drug effects*; D010146:Pain / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D010147:Pain Measurement; D010523:Peripheral Nervous System Diseases / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000187:drug effects*; D012584:Sciatic Nerve / Q000502:physiology
D000700:Analgesics; D004151:Dipeptides; D011957:Receptors, Opioid; C042591:kelatorphan