AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 5 547-G552, Copyright © 1984 by American Physiological Society
Inhibition of short-circuit current in rat ileum by aliphatic alcohols
Y. Fernandez, J. F. Desjeux, A. M. Dumontier and S. Mitjavila
The importance of the hydrophobic nature of the membrane in certain
functions of the intestinal epithelium was investigated by determining the
variations in short-circuit current (Isc), potential difference (PD), and
conductance (G) in rat ileum in the presence of the first eight alcohols in
the n-aliphatic series. At the lowest alcohol concentrations and in the
presence of Ringer-galactose, there was transitory stimulation of Isc and
PD that did not occur in the presence of theophylline or in the absence of
chloride. With or without theophylline all the alcohols tested inhibited
Isc and PD and slightly increased G as a function of their concentration.
The modifications in Isc were attributed to the inhibition of active sodium
transport. These results demonstrate a linear relation between the
logarithm of the concentrations causing 50% inhibition of Isc and the chain
length of the alcohols. The variations in free energy required to transfer
one -CH2- to the site at which the alcohols exert their activity were,
respectively, -582 and -589 cal in the presence and absence of
theophylline. These values show that the observed modifications in free
energy are due to solubilization of the alcohols in a very hydrophobic zone
of the tissue, confirming that the functional activities measured are
dependent on the hydrophobicity of the membrane.
