Calcium movements promoted by vesicles in a highly enriched sarcolemma preparation from canine ventricle. Calcium-calcium countertransport.

摘要: Calcium uptake by vesicles in a highly enriched sarcolemma preparation from canine ventricle was found to be markedly stimulated intravesicular calcium. Stimulation of calcium appeared saturable function efflux the reaction medium. uptake, supported calcium, and efflux, extravesicular were correspond on one-to-one basis. Only small changes net or observed occur response chemical gradients across membrane. It concluded, therefore, that under certain conditions, major means for movement is via exchange Sodium stimulate when present space space, but effects plus sodium not additive with respect stimulating either efflux. The unlabeled strontium, barium, magnesium similar though identical. temperature dependence calcium-stimulated sodium-stimulated movements characterized Q10 values 1.27 2.06, respectively. Previous work has associated sodium-calcium sarcolemma. argued study, turn, provides evidence calcium-calcium also In addition, results study are consistent hypothesis one membrane system can promote sodium.