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The chronic effects of neonatal alloxan-induced diabetes mellitus on ventricular myocyte shortening and cytosolic Ca2+.
MedLine Citation:
PMID:  20941530     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
Diabetes mellitus is a serious global health problem, and cardiovascular complications are the major cause of morbidity and mortality in diabetic patients. The chronic effects of neonatal alloxan- (ALX) induced diabetes mellitus on ventricular myocyte contraction and intracellular Ca(2+) transport have been investigated. Ventricular myocyte shortening was measured with a video edge detection system and intracellular Ca(2+) was measured in fura-2 loaded cells by fluorescence photometry. Diabetes was induced in 5-day old male Wistar rats by a single intraperitoneal injection of ALX (200 mg/kg body weight). Experiments were performed 12 months after ALX treatment. Fasting blood glucose was elevated and blood glucose at 60, 120 and 180 min after a glucose challenge (2 g/kg body weight, intraperitoneal) was elevated in diabetic rats compared to age-matched controls. Amplitude of shortening was significantly (P < 0.05) reduced in electrically stimulated myocytes from diabetic hearts (5.70 ± 0.24%) compared to controls (6.48 ± 0.28%). Amplitude of electrically evoked Ca(2+) transients was also significantly (P < 0.05) reduced in myocytes from diabetic hearts (0.11 ± 0.01 fura-2 ratio units) compared to controls (0.15 ± 0.01 fura-2 ratio units). Fractional sarcoplasmic reticulum Ca(2+) release was not significantly (P > 0.05) altered in myocytes from diabetic heart (0.70 ± 0.03 fura-2 ratio units) compared to controls (0.72 ± 0.03 fura-2 ratio units). Amplitude of caffeine-stimulated Ca(2+) transients was significantly (P < 0.05) reduced in myocytes from diabetic hearts (0.43 ± 0.02 fura-2 ratio units) compared to controls (0.51 ± 0.03 fura-2 ratio units). Area under the caffeine-evoked Ca(2+) transient was significantly (P < 0.05) reduced in myocytes from diabetic heart (0.77 ± 0.06 Vsec) compared to controls (1.14 ± 0.12 Vsec). Intracellular Ca(2+) refilling rate during electrical stimulation following application of caffeine was significantly (P < 0.05) slower in myocytes from diabetic heart (0.013 ± 0.001 V/sec) compared to controls (0.031 ± 0.007 V/sec). Depressed shortening may be partly attributed to depressed sarcoplasmic reticulum Ca(2+) transport in myocytes from neonatal ALX-induced diabetic rat heart.
Authors:
Frank Christopher Howarth; Zahra Hassan; Muhammad Anwar Qureshi
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-10-13
Journal Detail:
Title:  Molecular and cellular biochemistry     Volume:  347     ISSN:  1573-4919     ISO Abbreviation:  Mol. Cell. Biochem.     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2010-12-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0364456     Medline TA:  Mol Cell Biochem     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  71-7     Citation Subset:  IM    
Affiliation:
Department of Physiology, Faculty of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, UAE. chris.howarth@uaeu.ac.ae
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