ELECTROPHYSIOLOGICAL EFFECTS OF VERAPAMIL ON PRIMARY AND TRANSITIONAL PACEMAKER CELLS OF THE FROG-HEART

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dc.contributor.authorMORALES, M
dc.contributor.authorHERNANDEZ, D
dc.contributor.authorDEGUEVARA, RL
dc.contributor.authorGUERRERO, S
dc.date.accessioned2025-01-23T19:25:18Z
dc.date.available2025-01-23T19:25:18Z
dc.date.issued1988
dc.description.abstractIn spontaneously beating preparations of sinus venosus of the frog Caudiverbera caudiverbera the electro-physiologic effects of verapamil on action potential parameters of both primary and transitional pacemaker cells were investigated. Verapamil in concentrations ranging from 5 .times. 10-8 M to 2 .times. 10-6 M slowed the sinus rate and blocked impulse initiation. Action potential blockade was accompanied by oscillations of membrane potential and depolarization. During blockade of primary pacemaker cells, pacemaker shift originated the activation of transitional or atrial contractile fibres. Subthreshold concentrations of the drug to induce complete blockade (5 .times. 10-8 M) allowed to observe a greater depression of bioelectric cell characteristics in primary than in transitional fibres. Verapamil-induced blockade of transitional pacemaker action potentials was preceded by the appearance of a notch in their upstroke and the persistence of a fast depolarizing section that remained unblocked. This fast verapamil-resistant section of the upstroke was absent in preparations treated with tetrodotoxin (TTX). The results confirmed most previously described actions of verapamil on mammalian sinoatrial preparations and provided a pharmacological dissection of the two slow and fast bio-electric components contributing to the upstroke of transitional pacemaker cells of the frog sinus venosus.
dc.fuente.origenWOS
dc.identifier.issn0306-3623
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/99463
dc.identifier.wosidWOS:A1988N360700022
dc.issue.numero3
dc.language.isoen
dc.pagina.final430
dc.pagina.inicio425
dc.revistaGeneral pharmacology-the vascular system
dc.rightsacceso restringido
dc.subject.ods03 Good Health and Well-being
dc.subject.odspa03 Salud y bienestar
dc.titleELECTROPHYSIOLOGICAL EFFECTS OF VERAPAMIL ON PRIMARY AND TRANSITIONAL PACEMAKER CELLS OF THE FROG-HEART
dc.typeartículo
dc.volumen19
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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