[A study of passive Ca2+ flow through the sarcoplasmic reticulum of skeletal muscles. I. Passive Ca2+ efflux from vesicle membranes].
The same level of passively loaded Ca2+ was observed both in the heavy (enriched in terminal cisternae) and light (enriched in longitudinal reticulum) sarcoplasmic reticulum (SR) fractions. The level of passively loaded Ca2+ of the both SR fractions decreased in the presence of 150 mM K+. However the rate and extent of Ca2+ release was greater from heavy SR fraction. The rate of Ca2+ release under conditions of antiport of K+, Na+, choline+ and gluconate-, Cl-, SCH- increased proportion with their permeability through the SR membrane. The initial rate of Ca2+ release also became higher under equal concentration of monovalent cation chloride both inside and outside the SR vesicles. Apparently, in this case Ca2+ release occurs through Ca-channels which are open at a membrane potential.
Tugaĭ
V A
VA
Diadiusha
G P
GP
Zakharchenko
A N
AN
Zemlianaia
N N
NN
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D028021:Sodium-Potassium-Chloride Symporters
D002352:Carrier Proteins; D028021:Sodium-Potassium-Chloride Symporters; D012964:Sodium; D011188:Potassium; D002118:Calcium
Issledovanie passivnykh potokov Ca2+ cherez membranu sarkoplazmaticheskogo retikuluma skeletnykh myshts. I. Passivnyĭ vykhod Ca2+ iz membrannykh vezikul.