Effects of diabetes on ryanodine receptor Ca release channel (RyR2) and Ca2+ homeostasis in rat heart


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Yaras N., UĞUR M., Ozdemir S., GÜRDAL H., PURALI N., Lacampagne A., ...More

Diabetes, vol.54, no.11, pp.3082-3088, 2005 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 54 Issue: 11
  • Publication Date: 2005
  • Doi Number: 10.2337/diabetes.54.11.3082
  • Journal Name: Diabetes
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.3082-3088
  • Lokman Hekim University Affiliated: No

Abstract

The defects identified in the mechanical activity of the hearts from type 1 diabetic animals include alteration of Ca2+ signaling via changes in critical processes that regulate intracellular Ca2+ concentration. These defects result partially from a dysfunction of cardiac ryanodine receptor calcium release channel (RyR2). The present study was designed to determine whether the properties of the Ca2+ sparks might provide insight into the role of RyR2 in the altered Ca2+ signaling in cardiomyocytes from diabetic animals when they were analyzed together with Ca2+ transients. Basal Ca2+ level as well as Ca2+-spark frequency of cardiomyoctes isolated from 5-week streptozotocin (STZ)-induced diabetic rats significantly increased with respect to aged-matched control rats. Ca2+ transients exhibited significantly reduced amplitude and prolonged time courses as well as depressed Ca2+ loading of sarcoplasmic reticulum in diabetic rats. Spatio-temporal properties of the Ca2+ sparks in cardiomyocytes isolated from diabetic rats were also significantly altered to being almost parallel to the changes of Ca2+ transients. In addition, RyR2 from diabetic rat hearts were hyperphosphorylated and protein levels of both RyR2 and FKBP12.6 depleted. These data show that STZ-induced diabetic rat hearts exhibit altered local Ca2+ signaling with increased basal Ca2+ level. © 2005 by the American Diabetes Association.