Studies on Ion Permeability. I. What Determines the Rate of Na+ Ion Efflux from Frog Muscle Cells?
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چکیده
The study of ~a+ion efflux from single muscle fibers and multiple muscle fiber prep* rations led to the conclusion that both the fast and slow fraction originate from within. the same cells. The rate-limiting step for the slow fraction is shown, not to be membrane permeability but the rate of desorption from intracellular adsorption sites. The other fraction which is 4 to 8 times faster represents the rate of exchange between intracellular free Na+ ion and the external medium. The s ign i f i i ce of this fmding in relation to the minimally needed energy for the Na pump is discussed.
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تاریخ انتشار 2007