title: [Actions of chlorpheniramine and its isomers on the auricular fibers of the mammalian heart].
abstract: The effects of the antihistaminic agent, chlorpheniramine and its optical isomers, were studied on the transmembrane potentials of specialized atrial conducting tissue and ordinary auricular muscle fibers. On atrial myocardium fibers, both isomers increase the duration of the action potential to a different degree and they also reduce the maximum rate of rise of phase O or dV/dt. In specialized conducting atrial tissue, the levo isomer increase the duration of the action potential in a larger proportion than the dextro compound. This occurs at the expense of the repolarization process. The l-compound produces only minimal changes in the dV/dt. The effects observed on both types of atrial tissues leads us to conclude: 1) Either type of tissue responds differently to each optical isomer of chlorpheniramine; 2) the results confirm the participation of specialized conduction pathways in atrial flutter; 3) the levo isomer may be considered as a possible candidate for clinical trial in patients with atrial flutter.
mesh_terms: D000818:Animals; D002744:Chlorpheniramine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004285:Dogs; D006321:Heart / Q000187:drug effects*; D006325:Heart Atria / Q000187:drug effects; D006329:Heart Conduction System / Q000187:drug effects; D007536:Isomerism; D008564:Membrane Potentials / Q000187:drug effects
chemical_list: D002744:Chlorpheniramine
vernacular_title: Acciones de la clorofeniramina y sus isómeros sobre las fibras auriculares del corazón del mamífero.