[Pharmacological study on an irreversible ligand of opioid receptors, A-alpha-CAM, and its reaction with the sulfhydryl group].
A-alpha-CAM is an irreversible partial agonist of opiate receptors. Its binding to opioid receptors from P2 membrane preparations of rat brain and its effect on isolated tissues (GPI, MVD, RVD and RbVD) could not be washed away, indicating the irreversible nature of its binding. A-alpha-CAM inhibited the electrically elicited contraction of GPI, a pure agonist, with an IC50 of 2.6 mumol/L, and this effect could not be antagonized by Nx. A-alpha-CAM acted as a partial agonist on MVD with an IC50 of 0.153 mumol/L. With RVD and RbVD, A-alpha-CAM acted as an antagonist with PA2 values of 7.4 and 7.7 respectively. Possibly, covalent binding of A-alpha-CAM with the sulfhydryl groups of opioid receptors is the biochemical mechanisms responsible for its irreversible action.
Ye
C
C
Institute of Basic Medical Sciences, Beijing.
D000818:Animals; D001665:Binding Sites; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D008024:Ligands; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D011817:Rabbits; D051381:Rats; D011957:Receptors, Opioid / Q000187:drug effects*; D013797:Thebaine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects
D008024:Ligands; D011957:Receptors, Opioid; C061304:N-allyl-7-N,N-bis(beta-chloroethyl)amino-6,14-endoethenotetrahydronororipavine; D013797:Thebaine