The Effects of CO₂ and Hydrogen Ions on Active Na Transport in the Isolated Frog Skin

Abstract

FUNDER, J., 13. H. USSING and J. 0. WIETH. The efects of CO, and hydrogen ions on active No trmsport in the isolated frog skin. Acta physiol. scand. 1967. 71. 65-76.The effect of pH on the active sodium transport of the isolated frog skin has been investigated.The sodium tramsport has previously been considered to be particularly sensitive to lowering of pH in the soluti(m bathing the corium side of the skin. However, when pH was lowered by unilateral titration with carbon dioxide, the active sodium transport was more sensitive to changes of pH on the epidermal side than on the corium side of the skin. Raising bicarbonate concentration from 2.4 to 57.5 or I15 mM increased the tolerance to carbon dioxide. This effect of bicarbonate was exerted from the corium side of the skin. The differing responses seen in the presence of 2.4, 57.5, and I15 mM bicarbonate showed no direct correlation to pH of the media. When phosphate concentration was below 1 mM, lowering of pH to values between 6.5 and 5.8 with HCI or H,PO, in the medium on the corium side had only slight effect on the sodium transport. At phosphate concentrations of 5-6 mM the transport was found to be inhibited rapidly. The results suggest that the active sodium transport of the isolated frog skin is affected by conditions lowering the intracellular pH of the transporting cells.

Marginal Effect of Changes in Acid-Base Status in vitro on Rheogenic H⁺ and HCO^-₃ Secretion in Turtle Urinary Bladder

“…By contrast, a longer diffu sion pathway for CO2 due to the multiple cell layers of the turtle bladder arises when changes arc made in the serosal solution that most probably result in CO2 gradients within the preparation. A similar explanation has been proposed to account for the different effects of CO2 on each side of the isolated frog skin [15]. It should be pointed out that the data on mean cell pH was basically confirma tory of the predicted changes that would result according to the solutions that bathed the tissues; thus the DMO results provided support to a hypothesis based on other exper imental data we have simultaneously ob tained.…”

“…5). Alternatively, the effects of high CO2 levels on JH" are depen dent on the associated changes in cell acidity in a comparable manner to the effects of CO2 on sodium transport where addition of bicar bonate to the serosal bathing solution pro tects against the inhibitory effect of high CO2 on JNa+ [15]. A progressive decrease in cell pH is expected to occur during isohydric mucosal CO2 titration ( fig.…”

“…was added to the mucosa, the serosa, or both, stems from the location of the acid-secreting cells, which is restricted to the mucosa, and from the existence of multiple cell layers in the turtle bladder preparation which may impede CO2 diffusion across the preparation [15].…”

The role of buffer anions and protons in secretion by the rabbit mandibular salivary gland.

“…Of course it may be that the pH effect is due to changes in intracellular pH (cf. Funder et al 1967) in which case the striking pH dependence may reflect the readiness with which acetate crosses cell membranes. Comparable acetate experiments are available only for the pancreas (Swanson & Solomon, 1975;Case et al 1979).…”

Influence of extracellular bicarbonate on the short‐circuit current and intracellular free calcium of human cultured sweat duct cells

“…This might indicate that the presented HCO3-effects are mediated by sites that are accessible only from the cytoplasm, i.e. the Na+ reabsorption in CSDCs, reflected by I,SC (Pedersen, 1989;Larsen Novak & Pedersen, 1991), might be modified by pHi, as demonstrated in other tissues (Funder, Ussing & Wieth, 1967;Goldfarb, Egnor & Charney, 1988;Harvey, Thomas & Ehrenfeld, 1988). Any of the systems involved in net active Na+ transport in the CSDC might be influenced by pHi variations, i.e.…”