Control of Cl- transport in the operculum epithelium of Fundulus heteroclitus: long- and short-term salinity adaptation.

The eurohaline fish, Fundulus heteroclitus, adapts rapidly to enhanced salinity by increasing the ion secretion by gill chloride cells. An increase of approximately 70 mOsm in plasma osmolarity was previously found during the transition. To mimic this in vitro, isolated opercular epithelia of seawater-adapted Fundulus mounted in a modified Ussing chamber were exposed to an increase in NaCl and/or osmolarity on the basolateral side, which immediately increased I(SC).

Urea and water permeability in the ureotelic gulf toadfish (Opsanus beta).

The permeability of toadfish gills and skin to urea and water has been measured in order to investigate the mechanisms behind the pulsatile excretion of urea previously described in this species. A perfused gill preparation was used in the gill studies and isolated pieces of skin mounted in an Ussing chamber in the skin studies. Simultaneously, urea and water permeability was measured in vivo in free swimming fish.

Chloride cells and osmoregulation.

The chloride cells of the gill secretory epithelium of fish that make the transition from fresh water to sea water adapt to the increased salinity by responding to a rapid signal that stimulates chloride secretion. In this paper, data are presented supporting the view that the transient increase in plasma osmolarity that can be measured during the transition is responsible for the stimulation of chloride secretion. A maximal increase of 65 mOsm in the plasma of Fundulus heteroclitus (the killifish) was found during acclimation to sea water.

Chloride transport activation by plasma osmolarity during rapid adaptation to high salinity of Fundulus heteroclitus.

Transition from low salt water to sea water of the euryhaline fish, Fundulus heteroclitus, involves a rapid signal that induces salt secretion by the gill chloride cells. An increase of 65 mOsm in plasma osmolarity was found during the transition. The isolated, chloride-cell-rich opercular epithelium of sea-water-adapted Fundulus exposed to 50 mOsm mannitol on the basolateral side showed a 100% increase in chloride secretion, which was inhibited by bumetanide 10(-4) M and 10(-4) M DPC (N-Phenylanthranilic acid).

Inhibition of tumor promoter-mediated processes in mouse skin and bovine lens by caffeic acid phenethyl ester.

Caffeic acid phenethyl ester (CAPE) was isolated from propolis (a product of honeybee hives) that has been used in folk medicine as a potent antiinflammatory agent. CAPE is cytotoxic to tumor and virally transformed but not to normal cells. Our main goal was to establish whether CAPE inhibits the tumor promoter (12-O-tetradecanoylphorbol-13-acetate)-induced processes associated with carcinogenesis.