Surfactants and bioelectric properties of rat jejunum

The effects of surfactants on bioelectric properties of rat jejunum were determined. Tween 80 (nonionic) and sodium dodecylsulfate (anionic) increased transmural potential differences 20-34% over values in Krebs-Ringer bicarbonate buffer. Short-circuit currents increased 66-112% and net tissue resistance decreased 19-30%. The cationic surfactant cetrimide decreased transmural potential 23%; short-circuit current decreased 32%, and resistance increased 22%. When sulfate replaced chloride in buffer, surfactant effects were minimized or reversed suggesting a role of Cl- flux in the bioelectric effects. Cationic surfactant effects on current and resistance were in the same direction as, but of greater and lesser magnitude, respectively, than alterations observed with bile salts. The current increase was of greater magnitude and resistance decrease less marked. Surfactant molecules may interact specifically with membranes in a more complex manner than simple "detergency".