Characterization of L‐type calcium channel activity in atrioventricular nodal myocytes from rats with streptozotocin‐induced Diabetes mellitus

Physiological Reports

Kathryn H. Yuill²  Lina T. Al Kury¹ 

[1] College of Sustainability Sciences and Humanities, Zayed University, Abu Dhabi, UAE;Department of Biological, Biomedical and Analytical Sciences, University of the West of England, Bristol, United Kingdom

关键词: Atrioventricular node;    calcium channel;    cardiac;    diabetes;    ion channel;   

DOI  :  10.14814/phy2.12632

来源: Wiley

【 摘 要 】

Abstract

Cardiovascular complications are common in patients with Diabetes mellitus (DM). In addition to changes in cardiac muscle inotropy, electrical abnormalities are also commonly observed in these patients. We have previously shown that spontaneous cellular electrical activity is altered in atrioventricular nodal (AVN) myocytes, isolated from the streptozotocin (STZ) rat model of type-1 DM. In this study, utilizing the same model, we have characterized the changes in L-type calcium channel activity in single AVN myocytes. Ionic currents were recorded from AVN myocytes isolated from the hearts of control rats and from those with STZ-induced diabetes. Patch-clamp recordings were used to assess the changes in cellular electrical activity in individual myocytes. Type-1 DM significantly altered the cellular characteristics of L-type calcium current. A reduction in peak I_CaL density was observed, with no corresponding changes in the activation parameters of the current. L-type calcium channel current also exhibited faster time-dependent inactivation in AVN myocytes from diabetic rats. A negative shift in the voltage dependence of inactivation was also evident, and a slowing of restitution parameters. These findings demonstrate that experimentally induced type-1 DM significantly alters AVN L-type calcium channel cellular electrophysiology. These changes in ion channel activity may contribute to the abnormalities in cardiac electrical function that are associated with high mortality levels in patients with DM.

【 授权许可】

CC BY   
© 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

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