title: An in vitro study of the effects of calcium on the cardiovascular actions of thiopentone, althesin and ketamine in the rat.
abstract: The actions of three intravenous anaesthetics, Althesin, thiopentone and ketamine have been compared on the rat isolated atria and portal vein. Although the three anaesthetics had grossly similar actions on the two preparations. i.e. depression of atrial rate and depression of the amplitude of myogenic activity in the portal vein, there were enough differences to suggest that they produced their effects by different mechanisms. These differences were particularly obvious in interactions with noradrenaline and the effects of changes in calcium ion concentration on the concentration effect relationships for the agents on the atria and portal vein. Generally Althesin was unaffected by changes, but in qualitatively different ways.
mesh_terms: D000530:Alfaxalone Alfadolone Mixture / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D006325:Heart Atria / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D007649:Ketamine / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D011169:Portal Vein / Q000187:drug effects; D011277:Pregnanediones / Q000494:pharmacology*; D051381:Rats; D013874:Thiopental / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D011277:Pregnanediones; D007649:Ketamine; D000530:Alfaxalone Alfadolone Mixture; D013874:Thiopental; D002118:Calcium; D009638:Norepinephrine