WATER PERMEABILITY OF THE ORAL EPITHELIAL LAYERS OF THE SEA-ANEMONE, ANEMONIA-VIRIDIS

Citation
S. Benazettambutte et D. Allemand, WATER PERMEABILITY OF THE ORAL EPITHELIAL LAYERS OF THE SEA-ANEMONE, ANEMONIA-VIRIDIS, The Journal of experimental zoology, 279(1), 1997, pp. 1-8
Citations number
30
Categorie Soggetti
Zoology
ISSN journal
0022104X
Volume
279
Issue
1
Year of publication
1997
Pages
1 - 8
Database
ISI
SICI code
0022-104X(1997)279:1<1:WPOTOE>2.0.ZU;2-Z
Abstract
Water permeability of the oral epithelial layers of the anthozoan Anem onia viridis was studied. We determined a diffusional water permeabili ty of 17 x 10(-5) cm s(-1) and an osmotic water permeability of 2.5 10 (-5) cm s(-1). These permeability coefficients were independent of the state of contraction of the tentacle. Compared to other tissues, wate r permeability in sea anemones is relatively low. This result is quite surprising, since we determined in a previous study that the ionic pe rmeabilities of the oral epithelial layers of A. viridis were characte ristic of a leaky tissue (Benazet-Tambutte et al., '96a). The low wate r permeability of the oral epithelial layers of A. viridis can be cons idered as an adaptational mechanism for maintaining a hydrostatic skel eton. The ratio P-o/P-d was about 14. The osmotic flow was symmetric w hatever the direction of the gradient. Temperature did not affect diff usional water flux. Tile Arrhenius energy of activation for osmotic fl ux was about 5 kcal mol(-1). Osmotic water flow was insensitive to mer cury. Our results suggest the possible existence of HgCl2-insensitive water channels. (C) 1997 Wiley-Liss, Inc.