title: Drug-induced contractile responses in the isolated posterior communicating cerebral artery of the cat.
abstract: The isolated posterior communicating cerebral artery of the cat has been shown to have the ability to produce a contractile response to the following drugs; norepinephrine (NE), tyramine (Ty), 5-hydroxytryptamine (5-HT), histamine (H), acetylcholine (Ach) and potassium (K+). The changes in the contractile response were dose-dependent. The order of potencies of these vasoactive agents with respect to ED50 was: 5-HT greater than NE greater than Ach = H = Ty greater than K+. With regard to their ability to induce maximal contractile responses the order was: H = Ach greater than 5-HT = Ty greater than NE = K+. These results show that cerebral arteries are more sensitive to 5-HT than to NE, as opposed to extracranial arteries in which NE is generally the most potent vasoconstrictor agent.
mesh_terms: D000818:Animals; D002415:Cats; D002536:Cerebral Arteries / Q000187:drug effects*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D011188:Potassium / Q000494:pharmacology*; D013268:Stimulation, Chemical; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D014662:Vasoconstrictor Agents; D011188:Potassium