Chem. Senses 25: 167-172,
2000
© Oxford University Press 2000
Effects of Anion Substitution on Hydration Behavior and Water Uptake of the Red-spotted Toad, Bufo punctatus: is there an Anion Paradox in Amphibian Skin?
Department of Biological Sciences, University of Nevada, Las Vegas, NV, USA
Correspondence to be sent to: Karin von Seckendorff Hoff, Department of Biological Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4004, USA. e-mail: hoff{at}nevada.edu
Amphibians absorb water osmotically across their skins and rely on chemosensory information from the skin to assess the suitability of hydration sources. The time spent with skin in contact with a moist surface provides a quantitative measure of their ability to perceive the ionic and osmotic properties of aqueous solutions. Dehydrated toads given hyperosmotic (250 mM) solutions of NaCl or Na-gluconate showed significantly longer periods of hydration behavior on the gluconate solution, but they lost water osmotically when immersed in either solution. Similarly, dehydrated toads given 250 mM solutions of NaCl, Na-acetate, Na-phosphate or Na-gluconate showed a progressively greater length of hydration time on solutions with the larger mol. wt anions. These results are consistent with the chemosensory phenomenon previously described in mammalian tongue as ‘anion paradox’. On dilute (50 mM) solutions of NaCl or Na-gluconate, the hydration time was not different between anions, despite toads gaining water more rapidly when immersed in dilute NaCl than in Na-gluconate solutions. The differing behavioral results with hyperosmotic and hypoosmotic salt solutions suggest that chemosensory transduction through toad skin involves both transcellular and paracellular pathways.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  S. D. Hillyard, V. Baula, W. Tuttle, N. J. Willumsen, and E. H. Larsen Behavioral and Neural Responses of Toads to Salt Solutions Correlate with Basolateral Membrane Potential of Epidermal Cells of the Skin Chem Senses, October 1, 2007; 32(8): 765 - 773. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. L. Viborg, T. Wang, and S. D. Hillyard Cardiovascular and behavioural changes during water absorption in toads, Bufo alvarius and Bufo marinus J. Exp. Biol., March 1, 2006; 209(5): 834 - 844. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. D. Hillyard, J. Goldstein, W. Tuttle, and K. Hoff Transcellular and Paracellular Elements of Salt Chemosensation in Toad Skin Chem Senses, November 1, 2004; 29(9): 755 - 762. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Guo, S. D. Hillyard, and B. M. Fu A two-barrier compartment model for volume flow across amphibian skin Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2003; 285(6): R1384 - R1394. [Abstract] [Full Text] [PDF]
|
|