Document Detail


Osmoreception: Perspectives on signal transduction and environmental modulation.
MedLine Citation:
PMID:  22036842     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Osmoregulation is essential to life in vertebrates and osmoreception is a fundamental element in osmoregulation. Progress in characterizing the mechanisms that mediate osmoreception has been made possible by using a uniquely accessible cell model, the prolactin (PRL) cell of the euryhaline tilapia, Oreochromis mossambicus. In addition to a brief historical overview, we offer a summary of our recent progress on signal transduction and osmosensitivity in the tilapia PRL cell model. Prolactin is a central regulator of hydromineral balance in teleosts in freshwater (FW). Consistent with its essential role in FW osmoregulation, PRL release in tilapia is inversely related to extracellular osmolality, both in vivo and in vitro. Osmotically-driven changes in PRL cell volume control PRL release. A decrease in extracellular osmolality increases cell volume, leading to a rapid influx of Ca(2+) through stretch-activated channels followed by a sharp rise in PRL release. Our recent studies also suggest that cAMP is involved in the osmotic signal transduction, and that acclimation salinity can modulate PRL cell osmosensitivity. Prolactin cells from FW tilapia show a larger rise in PRL release after a reduction in medium osmolality than those from SW fish. Paradoxically, hyposmotically-induced increase in PRL mRNA was observed only in cells from SW fish. Our studies have revealed differences in the abundance of the water channel, aquaporin 3 (AQP3), and the stretch activated Ca(2+) channel, transient receptor potential vanilloid 4 (TRPV4) in PRL cells of FW and SW fish that may explain their differing osmosensitivity and osmoreceptive output in differing acclimation salinities.
Authors:
A P Seale; S Watanabe; E G Grau
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-10-20
Journal Detail:
Title:  General and comparative endocrinology     Volume:  -     ISSN:  1095-6840     ISO Abbreviation:  -     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-10-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370735     Medline TA:  Gen Comp Endocrinol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011. Published by Elsevier Inc.
Affiliation:
Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA.
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