Water permeability of the toad corneal epithelium: the effects of pH and amphotericin B

The water diffusional permeability of the toad cornea was evaluated from THO measurements, while taking into account the influence of unstirred layers. The corneal epithelium is a restrictive barrier for water diffusion and its permeability can be increased by amphotericin B or Triton X-100. In animals maintained in tap water, the epithelial water permeability was reversibly inhibited by the acidification of the solution bathing the tear side of the cornea. When toads were adapted to a saline environment, a reduction of epithelial water permeability with a loss of sensitivity to changes in the tear side medium pH was observed.