[Low temperature effects on sarcoplasmic reticulum membrane permeability for Ca2+].
The effect of rapid freezing down to--196 degree C was studied as applied to the functional activity of sarcoplasmic reticulum (SR) membranes Ca2+-pump. It is found that the SR Ca-transport system is damaged under the effect of low temperatures: the transport activity of Ca ions across the reticulum membrane is reduced simultaneously with a slight increase in the ATPase activity. The rate of Ca ions accumulation by SR  vesicles decreases and the magnitude of Ca: ATP ratio is reduced. The damage of the SR membrane Ca-transport system after freezing is related to an increase in the rate of the accumulated Ca2+ rapid leak from the vesicles through the system of active transport at the moment of ATPase "work" and to an increase in the rate of passive diffusion.
D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D005615:Freezing; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D010539:Permeability; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D000252:Calcium-Transporting ATPases; D002118:Calcium
Deĭstvie nizkikh temperatur na pronitsaemost' membran sarkoplazmaticheskogo retikuluma dlia Ca2+.