AJP - Renal Physiology, Vol 241, Issue 3 279-F288, Copyright © 1981 by American Physiological Society
Vasopressin, theophylline, PGE2, and indomethacin on active Na transport in frog skin: studies with microelectrodes
W. J. Els and S. I. Helman
Active transepithelial Na transport in frog skin is influenced by
vasopressin, theophylline, indomethacin, and PGE2. During stimulation or
inhibition of the short-circuit current, the transapical membrane voltage
of short-circuited skins was recorded using an intracellular
microelectrode. The microelectrode also permitted determination of the
fractional resistance of the apical barrier of the cells (fRo) and the E'1
(transepithelial voltage at which the apical membrane voltage is zero).
Analysis of the data according to an electrical model proposed previously
indicated that changes of ISC were mediated primarily via changes of the
slope resistance Rfo (Vo negative) of the apical barrier of the cells with
little or no effect on the Thevenin emf or resistance of the basolateral
membranes. These data are in accordance with previous observations that ADH
had no effect on the ENa and are discussed in relation to the origin of the
ENa at the basolateral membranes of the epithelial cells.
