A histamine-induced decrease of action potential duration in cardiac muscle mediated by the H2 receptors.
The effects of histamine (10(-7)--10(-5) M) on the cardiac action potential have been studied in ventricular strips of guinea pig heart, electrically driven at a constant rate. A decrease of action potential was constantly observed at histamine concentrations above 10(-6) M. No significant variations of the other electrophysiological parameters were induced by the amine. The decrease in the duration of the action potential was blocked by burimamide at a concentration (10(-4) M) which induced only a slight changes in action potential outline. It is suggested that the shortening of the repolarization phase induced by histamine is due to the H2 receptor-mediated activation of the calcium inward current, which can increase the intracellular calcium concentration influencing the potassium permeability.
D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D002049:Burimamide / Q000494:pharmacology; D003864:Depression, Chemical; D004347:Drug Interactions; D004558:Electric Stimulation; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006632:Histamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D011968:Receptors, Histamine / Q000502:physiology*; D011970:Receptors, Histamine H2 / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors
D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; D006632:Histamine; D002049:Burimamide