title: Photoaffinity labeling of opioid receptor with morphine-7,8-oxide (morphine epoxide).
abstract: The opioid receptor mediating inhibitory action of morphine in the electrically stimulated guinea pig ileum was irreversibly photoinactivated by morphine epoxide (3 X 10(-6) M). Morphine epoxide (up to 3 X 10(-5) M) did not influence the responses of rat vas deferens (epsilon-receptor) or rabbit vas deferens (kappa-receptor) to electrical stimulation. Effective concentrations of morphine epoxide were much lower in the guinea pig ileum (mu-receptor) than in the mouse vas deference (delta-receptor). The inhibitory action of [Met]-enkephalin on the twitch responses of the rat vas deferens and mouse vas deferens to electrical stimulation were not influenced after irradiation in the presence of morphine epoxide (3 X 10(-6) M). Therefore, morphine epoxide is probably a useful probe for photoaffinity labeling of the mu-receptor in vitro.
mesh_terms: D000345:Affinity Labels; D000818:Animals; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009022:Morphine Derivatives; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010777:Photochemistry; D010782:Photolysis; D011957:Receptors, Opioid / Q000187:drug effects* / Q000528:radiation effects; D014649:Vas Deferens / Q000187:drug effects
chemical_list: D000345:Affinity Labels; D009022:Morphine Derivatives; D011957:Receptors, Opioid