COMPARATIVE-STUDIES OF CA N-ACETYLHOMOTAURINATE AND CA N-ACETYLTAURINATE .2. PREVENTIVE AND OPPOSING ACTIONS OF THE ACUTE ETHANOL DEPLETIVEEFFECT ON THE IONIC TRANSFER THROUGH THE ISOLATED HUMAN AMNION

Ethanol reduces the ionic paraplacental transfer through the human amn ion. 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 opposin g actions of two taurine and homolaurine derivatives (Ca N-acetyltauri nate: ATACa, Ca N-acetylhomotaurinate: AOTACa) were observed On the ma ternal side, ATACa and AOTACa demonstrated protective actions on catio nic paracellular pathways and on the Na/K-ATPase pump with AOTACa only . On the fetal side, the effect of ATACa was limited to the sodium par acellular 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 ethano l effect and AOTAca exerted an antagonistic effect on the cation pump only. These results indicate that two closely related molecules may ha ve different effects on a membranous ethanol model.