西托溴铵

mAChR

Cimetropium Bromide behaves as a competitive antagonist of muscarinic-mediated contractions in isolated colonic preparations from both species, with affinity values (pA2) ranging between 7.41 and 7.82. Cimetropium has potent antimuscarinic effect in inhibition of contraction of longitudinal muscle preparations. In the superfusion experiments of the preparation which has been preloaded with labelled choline, Cimetropium decreases the labelled ACh release induced by electrical field stimulation under the muscarinic autoinhibition blocked-condition.

When administered intravenously to conscious dogs provided with a colonic Thiry fistula, Cimetropium is a potent inhibitor of large bowel motility evoked by both exogenous and endogenous stimuli. Cimetropium Bromide (10-100 μg/kg) counteracts colonic motor response to neostigmine administration with an ID ₅₀ of 27.9 μg/kg; both tonic and phasic components of contractile response are affected. In a comparable range of doses (3-100μg/kg), the drug inhibits motor activity elicited by intraluminal distension.