LAMELLAR JUNCTIONAL SARCOPLASMIC RETICULUM

Lamellar Junctional Sarcoplasmic Reticulum

This report deals with a description of an assembly of lamellar structures that have a morphology indistinguishable from that of cardiac junctional (1) and extended junctional (2) sarcoplasmic reticulum (SR). Briefly, junctional SR, a normal component of all myocardial cells, is that specialized portion of the SR which is periodically attached to sarcolemma by processes (junctional processes) i...

Role of sarcoplasmic reticulum junctional proteins in skeletal muscle strength

Background Skeletal muscle constitutes approximately 40% of body mass, and age-induced decrease of muscle strength impinge on daily activities and on normal social life in the elderly. Loss of muscle strength has been recognised as a debilitating and life threatening condition also in cachexia in cancer patients and in clinical conditions associated with prolonged bed rest. Skeletal muscle dihy...

Direct photoaffinity labeling of junctional sarcoplasmic reticulum with [14C]doxorubicin.

Doxorubicin, an anticancer drug, induces Ca2+ release from the terminal cisternae (TC) of skeletal muscle (Zorzato, F., Salviati, G., Facchinetti, T., and Volpe, P. (1985) J. Biol. Chem. 260, 7349-7355). Long wave ultraviolet irradiation of a TC fraction with morphologically intact feet structures (Saito, A., Seiler, S., Chu, A., and Fleischer, S. (1984) J. Cell Biol. 99, 875-885) in the presen...

Characterization of junctional and longitudinal sarcoplasmic reticulum from heart muscle.

Longitudinal tubules and junctional sarcoplasmic reticulum (SR) were prepared from heart muscle microsomes by Ca2+-phosphate loading followed by sucrose density gradient centrifugation. The longitudinal SR had a high Ca2+ loading rate (0.93 +/- 0.08 mumol.mg-1.min) which was unchanged by addition of ruthenium red. Junctional SR had a low Ca2+ loading rate (0.16 +/- 0.02 mumol.mg-1.min) which wa...

CHICKEN CARDIAC MUSCLE Its Elusive Extended Junctional Sarcoplasmie Reticulum and Sarcoplasmic Reticulum Fenestrations