The selectivity of acetylcholine (A-Ch)-activated channels for alkali cations, organic cations, and nonelectrolytes in cultured muscle cells has been studied. To test the effect of size, charge, and hydrogen-binding capacity of permeant molecules on their permeability, we have obtained the selectivity sequences of alkali cations, compared the permeability of pairs of permeant molecules with sim...

VARGAS, FERNANDO, AND JOHN A. JOHNSON, Permeability of rabbit heart capillaries to nonelectrolytes. Am. J. Physiol. 2 r 3(1> : 87-93. 1967. -Isolated perfused rabbit hearts were used to study the permeability characteristics of their capillaries with respect to inulin, raffinose, sucrose, and urea, The method used involved a continuous weighing of the isolated perfused heart. Each heart was iso...

After the development of the "black lipid membrane" techniques, studies of the permeability of labeled water and nonelectrolytes across these artificial membranes have yielded permeability constants comparable in magnitude to those obtained from tracer studies of living cell membranes. This general agreement has affirmed the belief that the living cell membranes are indeed closely similar to th...