Linked Life Data

1311410

Source:http://linkedlifedata.com/resource/pubmed/id/1311410

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1992-3-27
pubmed:abstractText
In various species, including humans, 5-hydroxytryptamine (5-HT) has been shown to exert positive chronotropic and inotropic cardiac effects through different types of receptors. The goal of the present study was to investigate the regulation by 5-HT of voltage-gated Ca2+ channels in human atrial myocytes and to characterize the receptor involved. Cardiomyocytes isolated enzymatically and mechanically were voltage-clamped using the whole-cell configuration of the patch-clamp technique. Extracellular perfusion of 5-HT increased Ca2+ current (ICa) amplitude with a EC50 (0.1 microM) similar to that observed with isoprenaline. The effects of 5-HT were blocked by the addition of protein kinase A inhibitor in the pipette. In addition, the effects of 5-HT, isoprenaline, and intracellular cAMP on ICa were not additive. These results support the hypothesis that the inotropic effect of 5-HT in human atrial myocytes is related to an increase of ICa via an elevation of intracellular cAMP levels and stimulation of cAMP-dependent protein kinase. The effects of 5-HT were not blocked by antagonists of 5-HT1 (methiothepin), 5-HT2 (ketanserin), or 5-HT3 (ICS 205-930 at a low concentration) receptors. The benzamide derivatives renzapride and zacopride and the azabicyclobenzimidazolone derivative BIMU 8 increased ICa, but less efficiently than did 5-HT or 5-methoxytryptamine. Moreover, ICS 205-930 at high concentrations (greater than 1 microM) completely antagonized the effects of 5-HT. Thus, the pharmacology of the 5-HT receptor involved in an increase of ICa in human atrial myocytes resembles that recently described for the 5-HT4 receptor. In atrial myocytes dissociated from rat, rabbit, guinea pig, or frog, 5-HT at high concentrations had no effect on Ca2+ currents, suggesting that the distribution of 5-HT4 receptors in cardiac tissues is species dependent.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0026-895X
pubmed:author
pubmed:issnType
Print
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
346-51
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Serotonin increases calcium current in human atrial myocytes via the newly described 5-hydroxytryptamine4 receptors.
pubmed:affiliation
CRBM, CNRS UPR 8402/INSERM U 249, Montpellier, France.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't