title: Possible role of slow sodium-calcium channels in the mechanism of changes in electrical and mechanical activity of guinea pig heart cells in local anaphylaxis (the isoptine effects).
abstract: The local anaphylactic reaction and the effects of histamine during blocking of the slow sodium-calcium channels by isoptine were investigated in the spontaneously contracting oracle of the atrium of a guinea pig previously sensitized to egg albumin. Simultaneously with the intracellular recording of the potentials, isometric contractions of the preparation were recorded by means of a mechanotron. The investigation showed that egg albumin (0.2 mg/ml) and histamine (0.1 mg/ml) are antagonists of isoptine (2-16 mg/liter) as regards its effect on automatic contraction and duration of the action potential. It is postulated that this anaphylatic reaction is based on activation of the slow sodium-calcium channels in the surface membrane of the myocardial fibers.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000707:Anaphylaxis / Q000378:metabolism / Q000503:physiopathology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000503:physiopathology*; D006632:Histamine / Q000494:pharmacology; D066298:In Vitro Techniques; D009206:Myocardium / Q000378:metabolism; D010047:Ovalbumin / Q000276:immunology / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D014700:Verapamil / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology
chemical_list: D006632:Histamine; D010047:Ovalbumin; D012964:Sodium; D014700:Verapamil; D002118:Calcium