selective m1 and m2 muscarinic receptor antagonists pirenzepine and af-dx 116 , respectively , were administered to open-chest , pentobarbital-anesthetized dogs to determine the muscarinic receptor subtype responsible for the preferential vasodilation of subendocardial blood vessels during intracoronary methacholine infusion .
C0384752
m2
C0034826
muscarinic receptor