Interaction between the Effects of Inside and Outside Na and K on Bullfrog Skin Potential

Abstract

The composition of the solution bathing one border of the isolated frog skin affects the response of the potential across the skin to changes in the composition of the solution bathing the opposite border. Increasing the K concentration of the inside (corium) bathing solution decreased the sensitivity of the potential to a change in outside Na concentration. Decreasing the outside Na concentration decreased the sensitivity of the potential to a change in inside K concentration. Increasing the total ionic strength of the outside bathing solution or of both bathing solutions decreased the sensitivity of the potential to a change in outside Na concentration.

Studies on chloride permeability of the skin ofLeptodactylus ocellatus: III. Na+ and Cl− effect on electrical phenomena

“…The concentration at which they found the inflection point (60 mM) is much higher than the one at which we find the inflection of the curve. Yet one has to take into account the fact that while we only change the outer bathing solution, Fischbarg et al (1967) changed both solutions at the same time and, as mentioned above, changes in the inner solution produce variations of its own (Leb et al, 1965;Rabito et al, 1973). Therefore, the possibility exists that the inflection of the At) curve reflects the activation of a passive site with a concomitant increase of the rate of C1 pumping, as demonstrated in the previous paper by Rotunno et al, (1978).…”

Interaction between cell sodium and the amiloride-sensitive sodium entry step in rabbit colon

“…Further, when the initial Ores was partially inhibited by graded doses of ouabain or amiloride or graded reductions in temperature, the changes in Ores resulting from an abrupt reduction in the Na concentration of the mucosal solution were linearly related to the initial Ores" The results obtained by Finn when active Na transport was completely inhibited with ouabain are entirely consistent with our finding that under these conditions the amiloride-sensitive Na entry step is blocked, probably due to an increase in cell Na; in all likelihood the same explanation can account for the results obtained when the temperature of the bathing media was reduced to 5 ~ In addition, the graded responses observed by Finn suggest that the Na conductance and the degree to which the outer or mucosal membrane approaches the behavior of a pure Na-electrode varies directly with the rate of active Na transport (pump activity). 7 A similar explanation may apply to the findings of Leb et al (1965) and Snell and Chowdhury (1965).…”