title: The possible involvement of Na+ ions in corticosterone-induced hypercontractility in the rat anococcygeus muscle.
abstract: The possibility that corticosterone-induced hypercontractility in the rat anococcygeus muscle might be due to an intramuscular redistribution of Na+ was investigated. 2 The contractility of the isolated muscle to noradrenaline (NA) was directly dependent on the Na+ concentration of the Krebs solution. 3 There was a linear relationship between the maximum contractile response of the muscle to NA and the Na+ concentration of the Krebs solution. 4 Muscle contractility was also increased by the presence of ouabain (10(-4)M) in the bathing medium. 5 Muscles from rats treated with corticosterone exhibited increases in both total and ouabain-sensitive ATPase activity. 6 The relationship between corticosterone, Na+ distribution, and muscle contractility is discussed.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D003345:Corticosterone / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000201:enzymology; D009638:Norepinephrine / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D010042:Ouabain; D012964:Sodium; D000251:Adenosine Triphosphatases; D003345:Corticosterone; D009638:Norepinephrine