Effects of varying intensity exercise on shortening and intracellular calcium in ventricular myocytes from streptozotocin (STZ)-induced diabetic rats.
This study examined the influence of two intensities of exercise on ventricular myocyte shortening and intracellular calcium in the streptozotocin (STZ)-induced diabetic rat. Animals were divided into four groups: control sedentary (CS), diabetic sedentary (DS), diabetic light exercise (DLE; 5 x 30 min/week, 9 m/min) and diabetic moderate exercise (DME; 5 x 30 min/week, 18 m/min) and the exercise programme started 2 months after STZ treatment. Time to peak (TPK) shortening was prolonged in myocytes from DS (112.1 +/- 2.5 ms) compared to CS (98.1 +/- 2.1 ms) rats and was not additionally altered by either light (117.0 +/- 2.1 ms) or moderate (115.4 +/- 2.0 ms) exercise. TPK of the Ca(2+) transient was not significantly altered by STZ treatment (69.4 +/- 2.4 ms) but was prolonged by light (79.8 +/- 3.5 ms) and moderate (76.6 +/- 2.9 ms) exercise compared to CS (65.5 +/- 2.7 ms). Data from this study suggest that the chosen intensities of exercise were ineffective in modulating the dynamics of cardiac muscle contraction and reversing the deleterious effects of diabetes on heart-muscle contraction.
Department of Physiology, Faculty of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, UAE. chris.howarth@uaeu.ac.ae
Frank Christopher
FC
Howarth
F A
FA
Almugaddum
M A
MA
Qureshi
M
M
Ljubisavljevic
M
M
Ljubisavijevic
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004558:Electric Stimulation; D006352:Heart Ventricles / Q000166:cytology*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism*; D009200:Myocardial Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D013311:Streptozocin
D001786:Blood Glucose; D002110:Caffeine; D013311:Streptozocin; D002118:Calcium