Dicyclomine discriminates between M1- and M2-muscarinic receptors in the guinea-pig ileum.
1. The affinity of the antagonist dicyclomine for subtypes of muscarinic receptors has been assessed in the myenteric plexus-longitudinal muscle preparation of the guinea-pig. 2. Dicyclomine had a high affinity (pA2 9.13) for the neuronal M1-receptor whose activation by pilocarpine causes an increase in acetylcholine release. Dicyclomine had a low affinity for both the prejunctional M2-receptor (pA2 7.61) mediating inhibition of the electrically-evoked acetylcholine release and the postjunctional M2-receptor (pA2 7.21). 3. It is concluded that dicyclomine distinguishes between M1- and M2-muscarinic receptors in functional experiments.
Kilbinger
H
H
Pharmakologisches Institut Universität, Mainz, F.R.G.
Stein
A
A
D000818:Animals; D003509:Cyclohexanecarboxylic Acids / Q000494:pharmacology*; D004025:Dicyclomine / Q000494:pharmacology*; D004558:Electric Stimulation; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D010095:Oxotremorine / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000187:drug effects*
D003509:Cyclohexanecarboxylic Acids; D011976:Receptors, Muscarinic; D004025:Dicyclomine; D010095:Oxotremorine