Comparative studies of Ca N-acetylhomotaurinate and Ca N-acetyltaurinate. II: Preventive and opposing actions of the acute ethanol depletive effect on the ionic transfer through the isolated human amnion

Ethanol reduces the ionic paraplacental transfer through the human amnion. This effect is exerted on the cationic paracellular pathway, the coupling between two adjacent epithelial cells, the monovalent cation pump and the antiport system. In this study, the preventive and opposing actions of two taurine and homotaurine derivatives (Ca N-acetyltaurinate : ATACa, Ca N-acetylhomotaurinate : AOTACa) were observed. On the maternal side, ATACa and AOTACa demonstrated protective actions on cationic paracellular pathways and on the Na/K-ATPase pump with AOTACa only. On the fetal side, the effect ofATACa was limited to the sodium paracellular pathway. This effect was total at 5 mM. On the maternal side, ATACa and AOTACa exhibited an opposing action on the same components of the conductance. But on the fetal side, ATACa increased the ethanol effect and AOTAca exerted an antagonistic effect on the cation pump only. These results indicate that two closely related molecules may have different effects on a membranous ethanol model.