Changes in cell membrane fluidity affect the sodium transport across frog skin and its sensitivity to amiloride.
1. 1-5 mM n-hexanol added to the outer (mucosal) medium of isolated skin of the frog Rana temporaria increases the short circuit current (Isc) across it. 2. This effect shows a saturable dependency on the outer sodium concentration, also when NaCl is replaced by Na2SO4. 3. n-Hexanol at a concentration of 1 mM, and cold acclimation of the frogs, which increases the fluidity of epidermal cell membranes, do not affect the sensitivity of Isc to the inhibiting effect of amiloride. 4. n-Hexanol at a concentration (5 mM) which causes a fluidization of cell membrane preparations from isolated frog epidermis also increases the sensitivity of Isc to amiloride. 5. The effects of low concentrations of n-hexanol and of cold acclimation probably depend on an increase of the permeability of apical membranes of epidermal cells to sodium caused by membrane fluidization. At higher concentrations of n-hexanol, a further disordering of the membrane structure occurs with a better access of amiloride to its action sites.
D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D000441:Hexanols / Q000494:pharmacology; D007700:Kinetics; D008560:Membrane Fluidity / Q000187:drug effects; D011896:Rana temporaria; D012867:Skin / Q000187:drug effects; D012879:Skin Physiological Phenomena
D000441:Hexanols; C036260:1-hexanol; D000584:Amiloride