Muscarinic Receptor Subtype in Isolated Dog and Monkey Facial Vein

Abstract

Using the cannula inserting method, we investigated vascular responses to ACh and McN-A-343 (a M₁-agonist) in isolated and perfused canine and simian facial veins in non-preconstricted conditions. ACh usually induced only a vasoconstriction, but McN-A-343 did not induce any significant vasoconstriction. It is concluded that canine and simian facial veins contain very few receptors of the muscarinic M₁-subtype; and according to previous studies, these vessels have abundant M₃-receptors.