The opioid receptors in the hamster vas deferens are of the delta-type.
The motor responses of the isolated vas deferens of the hamster were unaffected by opioid-receptor agonists which are selective for the mu- or kappa-receptor, while agonists which show degrees of selectivity for the delta-opioid receptor caused dose-related inhibition of the stimulation-evoked contractions. The agonist action of the enkephalins and their congeners was only apparent when various inhibitors of tissue peptidases were present. Responses to opioid agonists were antagonised in a competitive manner by naloxone and by the selective delta-receptor antagonist, ICI 174864. It is noteworthy that the benzomorphans bremazocine, ethylketocyclazocine and Mr 2034, which are agonists at kappa-receptors in other tissues, are antagonists at the delta-receptor of the hamster vas deferens. Thus, the vas deferens of the hamster contains opioid receptors only of the delta-type and may therefore provide a simple and specific test for the assay of activity at the delta-opioid receptor.
D000818:Animals; D006224:Cricetinae; D004558:Electric Stimulation; D004745:Enkephalins / Q000494:pharmacology; D005849:Gerbillinae; D066298:In Vitro Techniques; D008297:Male; D008647:Mesocricetus; D009119:Muscle Contraction / Q000187:drug effects; D009197:Myenteric Plexus / Q000378:metabolism; D009294:Narcotics / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011957:Receptors, Opioid / Q000378:metabolism*; D017465:Receptors, Opioid, delta; D014649:Vas Deferens / Q000378:metabolism*
D004745:Enkephalins; D009294:Narcotics; D011480:Protease Inhibitors; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta