ULTRASTRUCTURAL CHANGES IN THE SARCOPLASMIC RETICULUM IN ACUTE MYOCARDIAL ISCHEMIA

概要

論文の詳細を見る
We investigated the morphologic changes in the sarcoplasmic reticulum (SR) in acute myocardial ischemia, induced by occlusion of the coronary artery in the canine heart, by freeze-fracture of SR in situ and in vitro, and they were compared to the alterations in Ca^<++>-stimulated ATPase activity and protein composition of the isolated SR. Both SR in situ and the isolated SR exhibited typical intramembranous particles with diameters of 70 to 90 Å in freeze-fracture replicas. The intramembranous particle density of the P face in SR in situ was 3,319 ± 75 (mean ± SE) per μm^2 and that in the isolated SR was 2,667 ± 60 ; particles were more numerous on the concave (P) face than on the convex (E) face. In ischemia for 30 to 60 min a significant decrease in the number of particles was found in SR in situ, and the corresponding change was noted in the isolated SR. Simultaneous decreases in Ca^<++>-stimulated ATPase activity and the major ATPase protein of the SR were recognized. The close correlation of the changing pattern between the reduction in Ca^<++>-ports the suggestion that a large part of the intramembranous particles represent ATPase protein itself. Decrease in the SR membrane particles strongly suggests the degradation of ATPase protein in the process of ischemic myocardial injury.
社団法人日本循環器学会の論文
1986-09-20