title: The mechanism of contraction of rat aorta to various agonists.
abstract: To elucidate the mechanism of contraction of the smooth muscle of the rat's aorta, its response to norepinephrine (NE), 5-hydroxytrypatamine (5-HT) and potassium chloride (KCI) was determined before and after pretreatment with reserpine and beta-diethylamionethyl 2-2-diphenylpropyl acetate (SKF 525-A). Unlike the rabbit's aorta, contraction of the rat's aorta induced by NE was inhibited by SKF 525-A. After the induction of maximal contraction, SKF 525-A induced a graded rapid relaxation after KCl, less so after 5-HT, and least after NE. Pretreatment with reserpine failed to induce supersensitivity to NE. After incubation in a Ca++-free or Na+ and Ca++-free Krebs solution, the rat's aorta failed to contract even on the addition of Ca++ or NE.
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002118:Calcium / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D011335:Proadifen / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D012964:Sodium / Q000502:physiology; D013997:Time Factors
chemical_list: D012701:Serotonin; D011189:Potassium Chloride; D012110:Reserpine; D012964:Sodium; D011335:Proadifen; D002118:Calcium; D009638:Norepinephrine