EFFECT OF OCL- AND AG-TRANSPORT IN SARCOPLASMIC-RETICULUM( ON ACTIVE AND PASSIVE CALCIUM)

After hypochlorite (OCl-) treatment of aortic smooth muscle sarcoplas mic reticulum (SR), the membrane microviscosity increases considerably in annular lipid regions in comparison with protein-free regions. OCl - induces inhibition of active and enhancement of passive calcium tran sport in SR. Treatment of SR vesicles with Ag+ followed by OCl- treatm ent (but not in the reverse order) enhances the activating effect of O Cl- on passive calcium release from the vesicles. It is concluded that the enhancement effect is due to the OCl--induced increase in the pas sive permeability of SR membrane for Ca2+ as a result of pore formatio n in the lipid bilayer.