'n Vergelykende studie van enkele strukturele en funksionele eienskappe van die sarkoplasmiese retikulum van skelet- en hartspier

Abstract

During the excitation-contraction coupling of muscle tissue, the sarcotubular system, comprising transverse (T)-tubules and the sarcoplasmic reticulum (SR), plays an essential role by regulating free calcium concentrations within the sarcoplasm. Although effective procedures exist for the preparation of skeletal muscle SR, the lesser development of heart muscle SR and the presence of high mitochondrial concentrations complicate the isolation of pure heart muscle SR preparations. This study entails a comparative investigation of specific structural and functional properties of the SR in both skeletal and cardiac muscle. Through the evaluation of various isolation methods, it is demonstrated that a relatively pure heart muscle SR preparation can be successfully prepared. Furthermore, a specific technique is described that greatly improves the stability of the preparation, while conclusions are drawn regarding the fundamental causes of instability in heart muscle SR.