title: [The influence of adrenaline on the effects of halothane and enflurane on the myocardium. Papillary muscle of the cat (author's transl)].
abstract: In this paper the influence of epinephrine on the isolated papillary muscle has been investigated with respect to the myocardial effects of enflurane and halothane. The contractile properties have been described under isotonic conditions by the parameters "muscle length change", "velocity of shortening and under isometric conditions by the parameters "peak tension" and "maximum rate of tension development". The studies led to the following results: 1. Halothane and enflurane cause a dose-dependent decrease of the contractile properties of the cat papillary muscle. Averaged for all parameters the mycocardial depressant effect of halothane is 2.6 times higher than that of enflurane, referring to equal concentrations. 2. Epinephrine has a positive inotropic effect which is most pronounced under isotonic mode of contraction for "velocity of shortening" and during isometric conditions for "maximum rate of tension development". 3. The positive inotropic effect of epinephrine is partially neutralized by halothane and enflurane. There is, however, evidence that the relative decrease of contractility due to halothane and enflurane is diminished by epinephrine. This finding shows that the myocardial effects of inhalation anaesthetics are overestimated in in-vitro-experiments (because of the lack of exogenous epinephrine) in contrast to experiments with intact animals. As this finding is referring to both halothane and enflurane, there is no specific difference to be found concerning the myocardial effects in comparative studies, including both in-vitro and in-vivo conditions.
mesh_terms: D000818:Animals; D002415:Cats; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004737:Enflurane / Q000494:pharmacology*; D004837:Epinephrine / Q000494:pharmacology*; D006221:Halothane / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects*; D013268:Stimulation, Chemical
chemical_list: D004737:Enflurane; D006221:Halothane; D004837:Epinephrine
vernacular_title: Der Einfluss von Adrenalin auf die Myokardwirkung von Halothan und Enfluran. Papillarmuskel der Katze.