The cardiovascular effects of ergometrine in the experimental animal in vivo and in vitro.

The cardiovascular effects of ergometrine have been examined using animal models in vivo and in vitro. In rats in vivo the pressor effects of a standard dose of ergometrine were found to be dependent upon the anaesthetic used for the procedure. The pressor action of ergometrine was greater when urethane, an anaesthetic which produces both sympathetic and parasympathetic acitivity, was used. The in-vitro experiments, using isolated rabbit aorta and portal vein, failed to explain the phenomenon; they suggested that ergometrine has a direct action on the alpha-adrenoceptor in rabbits. No evidence was found to suggest that ergometrine inhibits noradrenaline uptake or its release from the nerve terminals.