Journal of Comparative Physiology B

, 178:957

Vasotocin has the potential to inhibit basolateral Na+/K+-pump current across isolated skin of tree frog in vitro, via its V2-type receptor/cAMP pathway

Authors

    • Department of Physiology, School of MedicineSaitama Medical University
  • Kayo Fujimaki
    • Department of Physiology, School of MedicineSaitama Medical University
  • Shigeru Hokari
    • Department of Biochemistry, School of MedicineSaitama Medical University
Orginal Paper

DOI: 10.1007/s00360-008-0278-4

Cite this article as:
Takada, M., Fujimaki, K. & Hokari, S. J Comp Physiol B (2008) 178: 957. doi:10.1007/s00360-008-0278-4

Abstract

Adult frog skin transports Na+ from the apical to the basolateral side across the skin. Antidiuretic hormone (ADH) is involved in the regulation of Na+ transport in both mammals and amphibians. We investigated the effect of arginine vasotocin (AVT), the ADH of amphibians, on the short-circuit current (SCC) across intact skin and on the basolateral Na+/K+-pump current across apically nystatin-permeabilized skin of the tree frog, Hyla japonica, in which the V2-type ADH receptor is expressed in vitro. In intact skin, 1 pM AVT had no effect on the SCC, but 10 nM AVT was sufficient to stimulate the SCC since 10 nM and 1 μM of AVT increased the SCC 3.2- and 3.4-fold, respectively (> 0.9). However, in permeabilized skin, AVT (1 μM) decreased the Na+/K+-pump current to 0.79 times vehicle control. Similarly, 500 μM of 8Br-cAMP increased the SCC 3.2-fold, yet 1 mM of 8Br-cAMP decreased the Na+/K+-pump current to 0.76 times vehicle control. Arachidonic acid (10−5 M) tended to decrease the Na+/K+-pump current. To judge from these in vitro experiments, AVT has the potential to inhibit the basolateral Na+/K+-pump current via the V2-type receptor/cAMP pathway in the skin of the tree frog.

Keywords

VasotocinAntidiuretic hormone (ADH)Na+/K+-pumpV2 receptor/cAMP pathwayFrog skin

Abbreviations

ADH

Antidiuretic hormone

AVT

Arginine vasotocin

8Br-cAMP

8-Bromoadenosine 3′, 5′-cyclic monophosphate

SCC

Short-circuit current

ENaC

Epithelial sodium channel

CCD

Cortical collecting duct

Copyright information

© Springer-Verlag 2008