Role of LVA Ca channels in norepinephrine-induced automatic activity in rat pulmonary vein myocardial sleeve
| العنوان: | Role of LVA Ca channels in norepinephrine-induced automatic activity in rat pulmonary vein myocardial sleeve |
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| المؤلفون: | C.O. Malecot |
| المساهمون: | Signalisation et Transports Ioniques Membranaires (STIM), Université de Poitiers-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Tours, CNRS, Société Française de Cardiologie, Université de Poitiers-Université de Tours-Centre National de la Recherche Scientifique (CNRS) |
| المصدر: | 20th Printemps de la Cardiologie 20th Printemps de la Cardiologie, Société Française de Cardiologie, Oct 2020, Grenoble ; e-congress, France. pp.254, ⟨10.1016/j.acvdsp.2020.03.132⟩ |
| بيانات النشر: | HAL CCSD, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | Inotrope, Catecholaminergic, medicine.medical_specialty, business.industry, [SDV]Life Sciences [q-bio], Atrial fibrillation, medicine.disease, K currents, Pulmonary vein, Norepinephrine (medication), [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Endocrinology, [SDV.MHEP.CSC]Life Sciences [q-bio]/Human health and pathology/Cardiology and cardiovascular system, Internal medicine, medicine, [SDV.MHEP.PHY]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO], Cardiology and Cardiovascular Medicine, business, Ca channel, K channels, medicine.drug |
| الوصف: | International audience; Introduction. Ectopic foci in pulmonary veins (PV) are involved in the onset of atrial fibrillation. Norepinephrine (NE) induces in rat PV cardiomyocytes (CM) an automatic activity in saw-tooth pattern (catecholaminergic automatic activity or CAA), consisting of bursts of slow action potentials which depends on Ca (upstroke) and Na (inter burst) channels. We have previously shown the coexistence in rat PVCM, of a fast LVA (FLVA) non selective TTX-sensitive cationic channel and of T-type Ca channels. Objective. To evaluate in male Wistar rat PV myocardial sleeve the contribution of these channels to triggering NE-induced ectopic foci. Methods. Whole-cell currents were studied at room temperature in enzymatically isolated PVCM. Mechanical activity of PV rings was recorded in an organ bath at 37°C and CAA was induced by application of 10µM NE. Results. The FLVA Ca current was increased by the Ca v 3.x blockers TTA-A2 (10-100nM, n=11) and NiCl 2 (40µM, n=9) whereas a large LVA Ca current, present in 10 out of 80 PVCM, was partially reduced by 100nM TTA-A2. Study of K currents revealed the presence in PVCM of an inward rectifying current sensitive to TRAM-34 (1µM, n=6), a blocker of the Ca-activated K channel SK4. In PV rings, the Ca v 3.x blocker TTA-A2 (1-5µM) decreased CAA incidence. Total arrhythmia duration, measured over the last 10min of drug application, was reduced as well as burst duration and the number of spontaneous twitches within a burst. On the other hand, 40µM NiCl 2 or 1-2µM TRAM-34 increased total arrhythmia duration by decreasing the interval between bursts (no significant effect on the burst characteristics). Only NiCl 2 had a significant negative inotropic effect (~80% inhibition of L-type calcium current). Conclusions. Our results suggest that Ca influx through Ca v 3.1 channels contribute to triggering bursts of automatic activity and that Ca v 3.2 Ca channels, through activation of SK4 channels, are involved in the regulation of the interval between bursts. |
| اللغة: | English |
| DOI: | 10.1016/j.acvdsp.2020.03.132⟩ |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ada29bde439973dc264921e446160f0e https://hal.archives-ouvertes.fr/hal-03089724 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....ada29bde439973dc264921e446160f0e |
| قاعدة البيانات: | OpenAIRE |
| DOI: | 10.1016/j.acvdsp.2020.03.132⟩ |
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