The permeability of the skin of a neotenous urodele amphibian, the mudpuppy Necturus maculosus.

Abstract

SUMMARY1. The permeability of the isolated skin of a neotenous urodele amphibian, the mudpuppy Necturus maculosus, to Na, C1, urea and water was measured.2. Unidirectional transcutaneous flux measurements and the action of ouabain and amiloride, showed that there was normally no active Cl or Na transport, nor a Cl/Cl exchange diffusion process.3. Amphotericin B initiated a transcutaneous potential difference and short-circuit current, which could be inhibited by ouabain.4. The short-circuit current was nearly equivalent to the net Na transport and this was also inhibited by ouabain.5. A transcutaneous active Na transport mechanism thus appears to be incipient in the mudpuppy but is limited by a low permeability of the outer barrier of the cells.6. Vasotocin increased the skin's diffusion permeability for water but had no effect on the influx of Na or urea. 7. The function of Necturus skin is in several respects unique compared to that of other amphibians.

Effects of Olive Oil Mill Waste Water (OMWW) on the Frog Larvae

“…The mechanism responsible for these declines includes various chemical pollution caused by pesticides, herbicides, fertilizers, destruction of habitats and global climate change (Sparling et al 2001;Blaustein and Kiesecker 2002;Khan and Law 2005;Koponen et al 2007). The skin of a frog is very permeable (Bentley and Yorio 1977) and the tadpole stage also relies on gills for breathing (Gargaglioni and Milsom 2007), both of these physiological characteristics make frogs and tadpoles very susceptible to a number of contaminants. Consequently, because frogs inhabit both in water and land, they are more likely to be exposed to environmental contaminants compared to many other animals.…”

Prolactin increases open-channel density of epithelial Na+channel in adult frog skin

“…Transcellular active Na + transport across the skin, measured as the amiloride-blockable short-circuit current (SCC), has been identified in a wide variety of anuran and urodelan genera, including Rana, Leptodactylus, Bufo, Cynops and Ambystome species (Bentley and Yorio, 1977;Rabito et al, 1978;Bentley and Baldwin, 1980;Hillyard et al, 1982;Takada, 1985;Takada and Komazaki, 1986;Takada and Hara, 1988). This transport develops during the climax stages of metamorphosis in the bullfrog, and is due to the development of an epithelial Na + channel (ENaC).…”