Possible involvement of muscarinic M1 and M3 receptor subtypes mediating vasodilation in isolated, perfused canine lingual arteries.
1. Using the cannula insertion method, muscarinic receptor subtypes were analysed in isolated, perfused canine lingual arteries preconstricted with phenylephrine. 2. Both acetylcholine and McN-A-343 induced a profound vasodilation in a dose-related manner. Acetylcholine-induced dilations were approximately 1000-times more potent than McN-A-343-induced dilation. 3. Acetylcholine-induced dilations were abolished after removal of the endothelium by intraluminal treatment with 1 mg saponin. 4. Acetylcholine-induced dilations were markedly inhibited by an M1/M3 receptor antagonist, 4-DAMP. Moreover, they were slightly, but significantly, inhibited by an M1 antagonist, pirenzepine, but never influenced by an M2 antagonist, AF-DX 116. Mc-N-A-343-induced vasodilations were inhibited by both 4-DAMP or pirenzepine. 5. These results suggest that there are abundant functional M3 and a few M1 receptors in the canine lingual artery that mediate vasodilation and that this vasodilation is dependent on the presence of an intact endothelium.
Department of Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan.
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Chiba
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Tsukada
D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000109:Acetylcholine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology; D010890:Pirenzepine / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000145:classification / Q000187:drug effects* / Q000502:physiology; D012503:Saponins / Q000494:pharmacology; D014059:Tongue / Q000098:blood supply*; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D010880:Piperidines; D011976:Receptors, Muscarinic; D012503:Saponins; D010890:Pirenzepine; D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride; C042375:4-diphenylacetoxy-1,1-dimethylpiperidinium; D000109:Acetylcholine