Comparison of the affinity constant of some muscarinic receptor antagonists with their displacement of [3H]quinuclidinyl benzilate binding in atrial and ileal longitudinal muscle of the guinea-pig.
The ability of the muscarinic receptor antagonists fenipramide, 4-diphenylacetoxy-N-methyl piperidine methiodide (4-DAMP) and secoverine to displace [3H]QNB binding was correlated with the inhibition of responses of cholinomimetics at muscarinic receptors in the atria and ileal longitudinal muscle of the guinea-pig. Fenipramide and 4-DAMP exhibited a 2-4 fold higher affinity for muscarinic receptors in ileal longitudinal muscle in both types of experiments. Secoverine exhibited no difference in affinity in the two tissues.
Choo
L K
LK
Mitchelson
F J
FJ
D000818:Animals; D001667:Binding, Competitive; D002217:Carbachol / Q000494:pharmacology; D004558:Electric Stimulation; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000378:metabolism*; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010276:Parasympatholytics / Q000378:metabolism*; D011812:Quinuclidines / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*
D010276:Parasympatholytics; D011812:Quinuclidines; D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D002217:Carbachol