INVESTIGADORES
TORIANO Roxana Mabel
artículos
Título:
Biophysical properties of epithelial water channels
Autor/es:
PARISI MARIO; AMODEO GABRIELA; CAPURRO CLAUDIA; DORR RICARDO; FORD PAULA; TORIANO ROXANA
Revista:
BIOPHYSICAL CHEMISTRY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 1997 p. 255 - 263
ISSN:
0301-4622
Resumen:
The biophysical models describing the structure of water pores or channels have evolved, during the last forty years, from a pure ?black box? approach to a molecular based proposal. The initial ?sieving pore? in which water and other molecules were moving together was replaced by a more restrictive model, where water is moving alone in a ?single file? mode. Aquaporins discovery and cloning [G.M. Preston, T.P. Carroll, W.B. Guggino, P. Agre, Science 256 (1992) 3651 leaded to the ?hour-glass model? and other alternative proposals, combining information coming from molecular biology experiments and two dimensional crystallography. Concerning water transfers in epithelial barriers the problem is quite complex, because there are at least two alternative pathways: paracellular and transcellular and three different driving forces: hydrostatic pressure, osmotic pressure or ?transport coupled? movements. In the case of ADH-sensitive epithelia it is more or less accepted that regulated water channels (AQP2), that can be inserted in the apical membrane, coexist with basolateral resident water channels (AQP3). The mechanism underlying the so-called ?transport associated water transfer? is still controversial. From the classical standing gradient model to the ion-water co-transport, different hypothesis are under consideration. Coming back to hormonal regulations, other than the well-known regulation by neuro-hypophysis peptides, a steroid second messenger, progesterone, has been recently proposed [P. Ford, G. Amodeo, C. Capurro, C. Ibarra, R. Dorr, P. Ripoche, M. Parisi, Am. 3. Physiol. 270 (1996) F880].