Procaine effect on the active and passive ionic transport through isolated epithelia

A study on the influence of procaine on both active and passive transport properties of isolated frog skin, at temperatures ranging between 15 and 25 degrees C and at increasing concentrations up to 2%, was carried out. The active transport of sodium as expressed by the short-circuit current, is inhibited when procaine is added to the solution bathing the inside of the skin, the inhibition being steeper at higher concentrations. No apparent effect of procaine with temperature was noticed. The Na and K ionic flows were measured by flam-photometric dosimetry allowing a 10(-5) Kg. m-2 s-1 sensitivity. The diffusional potassium flow through frog skin was stimulated, while the diffusional sodium flow was inhibited by procaine. The stimulation of potassium diffusion was more evident at lower procaine concentrations, whereas the inhibition of sodium diffusion was more evident at higher procaine concentrations.