QUANTITATIVE MAPPING OF INTRACELLULAR CATIONS IN THE HUMAN AMNIOTIC MEMBRANE

The effect of magnesium and taurine on the permeability of cell membra nes to monovalent cations has been investigated using the Bordeaux nuc lear microprobe. PIXE and RBS techniques have been used to provide qua ntitative measurements and ion distributions in the isolated amniotic membrane. This physiological model for cellular exchanges allowed us t o reveal the distribution of most elements involved in cellular pathwa ys and the modifications under different experimental conditions of in cubation in physiological fluids. The PIXE microanalysis provided an o riginal viewpoint on these mechanisms. Following this first study, the amnion compact lamina was found to play a role which was not, up to n ow, taken into account in the interpretation of electrophysiological e xperimentations. The release of some ionic species, such as K+, from t he epithelial cells, during immersion in isotonic fluids, could have b een hitherto underestimated.