These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effects of hypertonic stimuli and arginine vasotocin (AVT) on water absorption response in Japanese treefrog, Hyla japonica.
    Author: Maejima S, Yamada T, Hamada T, Matsuda K, Uchiyama M.
    Journal: Gen Comp Endocrinol; 2008 Jun; 157(2):196-202. PubMed ID: 18555070.
    Abstract:
    Anuran amphibians do not drink orally but absorb water osmotically through the highly permeable ventral skin. In this cutaneous water absorption, roles of the putative cerebral osmoreceptors and functions of arginine vasotocin (AVT) were examined in the central nervous system of the Japanese treefrog, Hyla japonica. Intracerebroventricular (ICV) or intralymphatic sac (ILS) administration of various hypertonic solutions (NaCl, mannitol and urea) significantly extended the residence time in water in a dose-dependent manner, suggesting facilitation of water absorption in frogs. ICV injection of AVT also increased significantly the residence time in a dose-dependent manner. The water absorption effect of AVT was significantly inhibited by pretreatment of ICV OPC-21268, a vasopressin V(1) receptor antagonist. But pre-ICV injection of OPC-31260, a vasopressin V(2) receptor antagonist, did not block the water absorption effect of AVT. Extension of the residence time induced by hyperosmotic NaCl (1000 mOsm) ICV injection was significantly inhibited by pretreatment of ICV OPC-21268. The present results showed that increases of osmotic pressure in plasma and/or cerebrospinal fluid stimulate water absorption response, suggesting that osmoreceptors are certainly present in the central nervous system and AVT may directly stimulate water absorption in the treefrog. It is also suggested that AVT activates cellular mechanisms via V(1)-like but not V(2)-like receptors in the central nervous system and facilitates water absorption response in the treefrog.
    [Abstract] [Full Text] [Related] [New Search]