Profile of activity of kappa receptor agonists in the rabbit vas deferens.
The purpose of this study was to investigate further the kappa opioid receptor selectivity of the field-stimulated isolated rabbit vas deferens preparation and to study the profile of a series of kappa agonists in this tissue. Agonists acting at mu, delta and sigma receptors were without detectable effect in the rabbit vas deferens. But a number of kappa agonists, including bremazocine, tifluadom, ethylketocyclazocine, ketocyclazocine, U-50,488 and Win 42,610 all depressed contractions, producing parallel dose-response curves. Mr 2034 generally produced a shallower dose-response curve and achieved a lower maximum effect, thus acting like a partial agonist. The effect of ethylketocyclazocine was not reduced by the irreversible mu antagonist, beta-funaltrexamine, confirming that it is not acting via mu receptors. Another group of drugs, including nalorphine, butorphanol and proxorphan, which produce an agonist action via kappa receptors in the guinea-pig ileum and mouse vas deferens, were antagonists in the rabbit vas deferens, suggesting that this tissue will only respond to high efficacy kappa agonists.
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D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology; D001575:Benzomorphans / Q000494:pharmacology; D002077:Butorphanol / Q000494:pharmacology; D003496:Cyclazocine / Q000031:analogs & derivatives / Q000494:pharmacology; D016314:Ethylketocyclazocine / Q000031:analogs & derivatives; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009269:Nalorphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D011817:Rabbits; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology*; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D014649:Vas Deferens / Q000187:drug effects
D000700:Analgesics; D001575:Benzomorphans; D011759:Pyrrolidines; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D001569:Benzodiazepines; D009270:Naloxone; D016314:Ethylketocyclazocine; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; C012395:ketazocine; C027248:bremazocine; D003496:Cyclazocine; D002077:Butorphanol; C035470:tifluadom; D009269:Nalorphine