PLOS ONE
| Autor: | Steven Poelzing, Gregory S. Hoeker, Rodolphe Katra, Steven M. Pogwizd, Ashleigh R. Hood |
|---|---|
| Přispěvatelé: | Biomedical Engineering and Mechanics, Fralin Biomedical Research Institute, School of Biomedical Engineering and Sciences |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Male
ventricular myocytes nervous-system Physiology lcsh:Medicine Action Potentials Adrenergic Stimulation 030204 cardiovascular system & hematology stimulation Calcium in biology 0302 clinical medicine Medicine and Health Sciences lcsh:Science Excitation Contraction Coupling ca2+ Sex Characteristics 0303 health sciences Multidisciplinary Heart failure Electrophysiology Dose–response relationship Cardiovascular Diseases Female Rabbits Arrhythmia Research Article medicine.medical_specialty Cardiology chemistry.chemical_element In Vitro Techniques Calcium Membrane Potential Contractility 03 medical and health sciences rectifier potassium current Internal medicine Receptors Adrenergic beta Heart rate Cardiovascular Diseases in Women medicine Animals up-regulation 030304 developmental biology Calcium metabolism repolarization Dose-Response Relationship Drug business.industry Myocardium lcsh:R Isoproterenol Biology and Life Sciences gender-differences Myocardial Contraction rat-heart Endocrinology chemistry lcsh:Q business |
| Zdroj: | PLoS ONE PLoS ONE, Vol 9, Iss 10, p e111411 (2014) |
| Popis: | Cardioprotection in females, as observed in the setting of heart failure, has been attributed to sex differences in intracellular calcium handling and its modulation by b-adrenergic signaling. However, further studies examining sex differences in badrenergic responsiveness have yielded inconsistent results and have mostly been limited to studies of contractility, ion channel function, or calcium handling alone. Given the close interaction of the action potential (AP) and intracellular calcium transient (CaT) through the process of excitation-contraction coupling, the need for studies exploring the relationship between agonist-induced AP and calcium handling changes in female and male hearts is evident. Thus, the aim of this study was to use optical mapping to examine sex differences in ventricular APs and CaTs measured simultaneously from Langendorff-perfused hearts isolated from naı¨ve adult rabbits during b-adrenergic stimulation. The non-selective b-agonist isoproterenol (Iso) decreased AP duration (APD90), CaT duration (CaD80), and the decay constant of the CaT (t) in a dosedependent manner (1–316.2 nM), with a plateau at doses $31.6 nM. The Iso-induced changes in APD90 and t (but not CaD80) were significantly smaller in female than male hearts. These sex differences were more significant at faster (5.5 Hz) than resting rates (3 Hz). Treatment with Iso led to the development of spontaneous calcium release (SCR) with a dose threshold of 31.6 nM. While SCR occurrence was similar in female (49%) and male (53%) hearts, the associated ectopic beats had a lower frequency of occurrence (16% versus 40%) and higher threshold (100 nM versus 31.6 nM) in female than male hearts (p,0.05). In conclusion, female hearts had a decreased capacity to respond to b-adrenergic stimulation, particularly under conditions of increased demand (i.e. faster pacing rates and ‘‘maximal’’ levels of Iso effects), however this reduced badrenergic responsiveness of female hearts was associated with reduced arrhythmic activity. Published version |
| Databáze: | OpenAIRE |
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