Effects of ischemia and ischemia-reperfusion on sarcoplasmic reticulum structure and function in rat skeletal muscle

Abstract

The primary objective for this thesis was to investigate the changes that occur in the regulation of intracellular Ca2+ ([Ca2+]f) in skeletal muscle by the sarcoplasmic reticulum (SR) during ischemia (I) and ischemia-reperfusion (IR). In particular, the effects of I and IR on SR Ca2+ uptake, Ca2+ release and Ca2+-ATPaseactivity, measured in homogenates and isolated SR vesicles in vitro, were determined. In addition, the fluorescent probes, fluorescein isothiocyanate (FITC) and [(N-cyclohexyl-N'-dimethylamino-a-napthyl)carbodiimide] (NCD-4) , were used to measure structural alterations to the ATP binding site and the Ca2+ binding sites of the CA2+-ATPase, respectively, with I and IR.

In the first study, an in vivo model of prolonged I in rat skeletal muscle was employed. To induce total I, a tourniquet was placed around the upper hindlimb in 30 female Sprague-Dawley rats, weighing 256 +_ 6.7g (mean +_ SE), and inflated to 350 mmHg for 4 hours.