AJP - Gastrointestinal and Liver Physiology, Vol 238, Issue 4 298-G302, Copyright © 1980 by American Physiological Society
Asymmetry in osmotic response of frog gastric mucosa
L. Villegas
The effects of hyperosmolality of the serosal and mucosal bathing solutions
on the transmucosal net water and ion fluxes were studied in frog gastric
mucosa. Addition of 100 mosM glucose to the solution at the serosal surface
produces a reversed mucosal-to-serosal net water flux of 7.1 +/- 1.4
microliter . cm-2 . h-1. When added to the abolished spontaneous net water
flux, this results in an increment in the net water flux of -17.8 +/- 1.4
microliter . cm-2 . h-1. Addition of the same amount of glucose to the
solution at the mucosal surface produces an increment in the
serosal-to-mucosal net water flux of 3.7 +/- 1.1 microliter . cm-2 . h-1
when the solution at the opposite surface was kept in 220 mosmol/kg H2O.
Simultaneous increments of both solutions of 320 to 420 and 420 to 520 mosM
changes the osmotic serosal-to-mucosal induced fluxes to 1.9 +/- 0.9 and
3.4 +/- 1.6 microliter . cm-2 . h-1, respectively. The initial spontaneous
net water fluxes measured in 220, 320, and 420 mosM solutions were 11.3 +/-
0.9, 6.9 +/- 1.6, and -1.5 +/- 1.5 microliter . cm-2 . h-1. It is proposed
that the osmotic water flux is asymmetric, independent of the solutions
tonicities, and not significantly affected by the sweep of solutes at the
mucosal surface.
