Meeting Abstract

P1.138  Tuesday, Jan. 4  Localization and Quantification of Aquaporin 1, 2, and 4 Expression in Ventral Skin of the Rough-Skinned Newt (Taricha granulosa) LANE, RS*; POWERS, DR; SCHMITT, JM; George Fox University, Newberg, OR; George Fox University, Newberg, OR; George Fox University, Newberg, OR rlane08@georgefox.edu

Skin permeability to water in Urodele amphibians is a two-edged sword in that it allows absorption of moisture from the environment yet also promotes dehydration by evaporative water loss. Like other tissues bulk water flow across the skin occurs through aquaporin water channels (AQP), some of which are likely regulated to control either inward or outward water flow depending environmental conditions. However, the specific AQPs involved in water flow across Urodele skin and their associated regulatory pathways have not been well described. In this study we used immunofluorescence (IF) and Western blotting to localize and quantify the expression of AQP 1, 2, and 4 homologs in the ventral skin of rough-skinned newts (Taricha granulosa) acclimated to both terrestrial and aquatic environments. We hypothesized that terrestrial acclimated newts would up-regulate AQP1, 2 and 4 expression in their ventral skin, compared to aquatic acclimated newts, to facilitate water uptake. AQP1 was expressed equally in aquatic and terrestrial newts and localized in dermal capillary endothelium. AQP2 and AQP4 increased 36 and 100%, respectively in aquatic newts contrary to our hypothesis. AQP2 was localized in the outer layers of the stratum corneum and AQP4 in the sub-dermal tela subcutanea. The reduction of AQP2 and 4 in terrestrial newts suggests protection from desiccation is more critical to the newts than enhancing water influx through the ventral skin. AQP1 appears to traffic water into and out of circulation in the skin and might not require regulation.