Linked Life Data

17201746

Source:http://linkedlifedata.com/resource/pubmed/id/17201746

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
2007-1-4
pubmed:abstractText
1. 5-Hydroxytryptamine (5-HT) has an important role in the pathogenesis of irritable bowel syndrome. To investigate the effects of 5-HT on the contractile activity of myocytes of the guinea-pig proximal colon, cell imaging before and after contraction was undertaken and images were analysed using image-analysis software. Ion currents and membrane potentials were measured. Cytoplasmic free Ca(2+) was recorded using a confocal microscope following loading of the cells with the fluorescent probe Fura-2AM. 2. 5-Hydroxytryptamine reduced cell length in a dose-dependent manner (EC(50) = 0.189 micromol/L). Under current clamp, 10 micromol/L 5-HT reduced action potential amplitude (measured as peak height) and decreased action potential duration, as well as depolarizing the resting potential from -68.4 +/- 3.6 to -22.96 +/- 4.65 mV. Iberiotoxin (1 micromol/L) blocked the effects of 5-HT in reducing the time to repolarization (T(90)) and nicardipine (5 micromol/L) blocked the effects of 5-HT in reducing action potential amplitude. 3. In the whole-cell mode, 5-HT enhanced L-type Ca(2+) currents, large conductance K(+) channel (BK(Ca)) currents and spontaneous transient outward currents (STOC). In addition, 5-HT increased intracellular Ca(2+) levels. Ondansetron (10 micromol/L) blocked the effects of 5-HT in enhancing L-type Ca(2+) currents, BK(Ca) currents and STOC. 4. In conclusion, 5-HT induces contraction of colonic myocytes, mostly as a result of Ca(2+) release from the sarcoplasmic reticulum (SR) following activation of 5-HT(3) receptors and the inositol 1,4,5-trisphosphate pathway. In addition, the effect of 5-HT in decreasing action potential amplitude is mediated by the release of Ca(2+) from the SR, as well as by enhanced L-type Ca(2+) current. 5-Hydroxytryptamine decreased action potential duration by enhancing BK(Ca) current.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0305-1870
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
120-8
pubmed:meshHeading
pubmed:articleTitle
Mechanisms mediating serotonin-induced contraction of colonic myocytes.
pubmed:affiliation
Department of Gastroenterology, Renmin Hospital, Wuhan University, Wuhan, China.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't