Linked Life Data

18180374

Source:http://linkedlifedata.com/resource/pubmed/id/18180374

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2008-3-18
pubmed:abstractText
Neuromedin U (NmU) is a neuropeptide showing high levels of structural conservation across different species. Since its discovery in 1985, NmU has been implicated in numerous physiological roles, including smooth muscle contraction, energy homeostasis, stress, intestinal ion transport, pronociception, and circadian rhythm. Two G-protein-coupled receptors have been identified for NmU and cloned from humans, rats, and mice. Recombinantly expressed NmU receptors couple to both Galpha(q/11) and Galpha(i) G-proteins, and NmU binds essentially irreversibly, preventing signaling to repetitive applications of NmU. However, it is unclear whether these properties reflect those of endogenously expressed NmU receptors or how these properties influence the functional consequences of NmU receptor signaling. Here, we have explored the signaling by rat NmU receptors expressed endogenously in cultured rat colonic smooth muscle cells and explore the functional consequence of this signaling by investigating the NmU-mediated contraction of ex vivo rat colonic smooth muscle preparations. We demonstrate that endogenous rat NmU receptors couple to both Galpha(q/11) and Galpha(i) G-proteins. Furthermore, we show complex patterns of Ca(2+) signaling, including oscillations, and provide evidence of essentially irreversible binding of NmU to smooth muscle cells. Challenge of either circular or longitudinal rat isolated colonic smooth muscle preparations with NmU resulted in robust contractions. Stimulation was direct, and paradoxically, repetitive applications of NmU mediated repetitive contractions with no evidence of desensitization, highlighting a major discrepancy in the behavior of NmU in single cells and in intact tissues. The reason for this discrepancy is presently unknown.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1521-0103
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
325
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
154-64
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Paradoxical behavior of neuromedin U in isolated smooth muscle cells and intact tissue.
pubmed:affiliation
Department of Cell Physiology and Pharmacology, Medical Sciences Building, University of Leicester, University Road, Leicester LE1 9HN, UK.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't