HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 293/6/H3584    most recent 00619.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Yaras, N. Articles by Turan, B. Search for Related Content PubMed PubMed Citation Articles by Yaras, N. Articles by Turan, B.

Sex-related effects on diabetes-induced alterations in calcium release in the rat heart

¹Departments of Biophysics, Faculty of Medicine, Ankara University, and ²Hacettepe University, Ankara, Turkey; and ³Institut National de la Santé et de la Recherche Médicale U637, Physiopathologie Cardiovasculaire, CHU Arnaud de Villeneuve, Montpellier, France

Submitted 28 May 2007 ; accepted in final form 19 September 2007

The present study was designed to determine whether the properties of local Ca²⁺ release and its related regulatory mechanisms might provide insight into the role of sex differences in heart functions of control and streptozotocin-induced diabetic adult rats. Left ventricular developed pressure, the rates of pressure development and decay (±dP/dt), basal intracellular Ca²⁺ level ([Ca²⁺]_i), and spatiotemporal parameters of [Ca²⁺]_i transients were found to be similar in male and female control rats. However, spatiotemporal parameters of Ca²⁺ sparks in cardiomyocytes isolated from control females were significantly larger and slower than those in control males. Diabetes reduced left ventricular developed pressure to a lower extent in females than in males, and the diabetes-induced depressions in both +dP/dt and –dP/dt were less in females than in males. Diabetes elicited a smaller reduction in the amplitude of [Ca²⁺]_i transients in females than in males, a smaller reduction in sarcoplasmic reticulum-Ca²⁺ load, and less increase in basal [Ca²⁺]_i. Similarly, the elementary Ca²⁺ events and their control proteins were clearly different in both sexes, and these differences were more marked in diabetes. Diabetes-induced depression of the Ca²⁺ spark amplitude was significantly less in females than in matched males. Levels of cardiac ryanodine receptors (RyR2) and FK506-binding protein 12.6 in control females were significantly higher than those shown in control males. Diabetes induced less RyR2 phosphorylation and FK506-binding protein 12.6 unbinding in females. Moreover, total and free sulfhydryl groups were significantly less reduced, and PKC levels were less increased, in diabetic females than in diabetic males. The present data related to local Ca²⁺ release and its related proteins describe some of the mechanisms that may underlie sex-related differences accounting for females to have less frequent development of cardiac diseases.

calcium sparks; calcium transient; ryanodine receptors; Type 1 diabetes; excitation-contraction coupling