Living with a leaky skin: upregulation of ion transport proteins during sloughing

Wu, Nicholas C., Cramp, Rebecca L. and Franklin, Craig E. (2017) Living with a leaky skin: upregulation of ion transport proteins during sloughing. Journal of Experimental Biology, 220 11: 2026-2035. doi:10.1242/jeb.151738


Author Wu, Nicholas C.
Cramp, Rebecca L.
Franklin, Craig E.
Title Living with a leaky skin: upregulation of ion transport proteins during sloughing
Journal name Journal of Experimental Biology   Check publisher's open access policy
ISSN 0022-0949
1477-9145
Publication date 2017-06-01
Year available 2017
Sub-type Article (original research)
DOI 10.1242/jeb.151738
Open Access Status Not yet assessed
Volume 220
Issue 11
Start page 2026
End page 2035
Total pages 10
Place of publication Cambridge, United Kingdom
Publisher Company of Biologists
Language eng
Abstract Amphibian skin is a multifunctional organ providing protection from the external environment and facilitating the physiological exchange of gases, water and salts with the environment. In order to maintain these functions, the outer layer of skin is regularly replaced in a process called sloughing. During sloughing, the outermost layer of the skin is removed in its entirety, which has the potential to interfere with skin permeability and ion transport, disrupting homeostasis. In this study, we measured, in vivo, the effects of sloughing on the cutaneous efflux of ions in toads Rhinella marina kept in freshwater conditions. We also measured transepithelial potential, cutaneous resistance, active ion transport and the distribution, abundance and gene expression of the key ion transport proteins sodium-potassium ATPase (NKA) and epithelial sodium channel (ENaC) during sloughing. We hypothesised that the increase in transepithelial efflux of ions during sloughing is a consequence of increased permeability and/or a reduction in the abundance or expression of cutaneous ion transport proteins, resulting in disruption of internal ion homeostasis. There was a significant increase in sodium and chloride efflux during sloughing in R. marina However, although in vitro skin resistance decreased after sloughing, active sodium transport increased commensurate with an increase in NKA and ENaC protein abundance in the skin. These changes in skin function associated with sloughing did not affect the maintenance of internal electrolyte homeostasis. These results suggest that during sloughing, amphibians actively maintain internal homeostasis by increasing cutaneous rates of ion uptake.
Formatted abstract
Amphibian skin is a multifunctional organ providing protection from the external environment and facilitating the physiological exchange of gases, water and salts with the environment. In order to maintain these functions, the outer layer of skin is regularly replaced in a process called sloughing. During sloughing, the outermost layer of the skin is removed in its entirety, which has the potential to interfere with skin permeability and ion transport, disrupting homeostasis. In this study, we measured, in vivo, the effects of sloughing on the cutaneous efflux of ions in toads Rhinella marina kept in freshwater conditions. We also measured transepithelial potential, cutaneous resistance, active ion transport and the distribution, abundance and gene expression of the key ion transport proteins sodium-potassium ATPase (NKA) and epithelial sodium channel (ENaC) during sloughing. We hypothesised that the increase in transepithelial efflux of ions during sloughing is a consequence of increased permeability and/or a reduction in the abundance or expression of cutaneous ion transport proteins, resulting in disruption of internal ion homeostasis. Therewas a significant increase in sodium and chloride efflux during sloughing in R. marina. However, although in vitro skin resistance decreased after sloughing, active sodium transport increased commensurate with an increase in NKA and ENaC protein abundance in the skin. These changes in skin function associated with sloughing did not affect the maintenance of internal electrolyte homeostasis. These results suggest that during sloughing, amphibians actively maintain internal homeostasis by increasing cutaneous rates of ion uptake.
Keyword Amphibian
Homeostasis
Moulting
QPCR
Sodium transport
Western blotting
Q-Index Code C1
Institutional Status UQ

 
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