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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1989-8-11
|
| pubmed:abstractText |
Our previous studies with fluoride have indicated that G-proteins may mediate the gating of Ca++ channels in vascular smooth muscle (VSM). We now present further studies on the relationship between G-proteins and Ca++ channels in VSM using guanosine-5'-(gamma-thio)triphosphate (GTP gamma S), a hydrolysis-resistant analog of GTP. Rat tail artery helical strips pretreated with GTP gamma S in a cytosol-like solution contracted in a Ca++-dependent manner in the absence of a depolarizing concentration of K+, hormones or any other Ca++ agonists. Contraction was dependent on the concentrations of applied GTP gamma S. The ability of strips pretreated with GTP gamma S to contract in response to Ca++ was not reversed by repeated washing. Incubation with 1 mM GTP applied extracellularly did not induce tension development. Treatment with a subthreshold concentration of GTP gamma S shifted the K+ concentration-related tension curve to the left but did not alter the maximum response. The contractions induced by GTP gamma S pretreatment and by submaximal (60 mM) KCI were additive at all levels of Ca++ tested. Extra tension development could be evoked from tissue maximally contracted with GTP gamma S by adding maximal K+ and norepinephrine. The relaxing sensitivity of the GTP gamma S-related contraction to reversal by nifedipine was between those for K+ depolarization and norepinephrine, and the GTP gamma S-induced rise in tension was partially inhibited by the Ca++ channel blocker nifedipine. Ca++-elicited contraction of the GTP gamma S-pretreated strips was relaxed by forskolin, an adenylate cyclase activator, 3-isobutyl-l-methyl-xanthanine, a cyclic nucleotide phosphodiesterase inhibitor, and dibutyryl cyclic AMP.(ABSTRACT TRUNCATED AT 250 WORDS)
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/1-Methyl-3-isobutylxanthine,
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Bucladesine,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Calcium Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Forskolin,
http://linkedlifedata.com/resource/pubmed/chemical/GTP-Binding Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Guanosine 5'-O-(3-Thiotriphosphate),
http://linkedlifedata.com/resource/pubmed/chemical/Guanosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Nifedipine,
http://linkedlifedata.com/resource/pubmed/chemical/Norepinephrine,
http://linkedlifedata.com/resource/pubmed/chemical/Thionucleotides
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Jul
|
| pubmed:issn |
0022-3565
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
250
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
352-7
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:2473191-1-Methyl-3-isobutylxanthine,
pubmed-meshheading:2473191-Adenosine Triphosphate,
pubmed-meshheading:2473191-Animals,
pubmed-meshheading:2473191-Arteries,
pubmed-meshheading:2473191-Bucladesine,
pubmed-meshheading:2473191-Calcium,
pubmed-meshheading:2473191-Calcium Channels,
pubmed-meshheading:2473191-Forskolin,
pubmed-meshheading:2473191-GTP-Binding Proteins,
pubmed-meshheading:2473191-Guanosine 5'-O-(3-Thiotriphosphate),
pubmed-meshheading:2473191-Guanosine Triphosphate,
pubmed-meshheading:2473191-Kinetics,
pubmed-meshheading:2473191-Male,
pubmed-meshheading:2473191-Muscle, Smooth, Vascular,
pubmed-meshheading:2473191-Nifedipine,
pubmed-meshheading:2473191-Norepinephrine,
pubmed-meshheading:2473191-Rats,
pubmed-meshheading:2473191-Rats, Inbred Strains,
pubmed-meshheading:2473191-Thionucleotides,
pubmed-meshheading:2473191-Vasoconstriction
|
| pubmed:year |
1989
|
| pubmed:articleTitle |
Guanine nucleotide binding proteins may modulate gating of calcium channels in vascular smooth muscle. II. Studies with guanosine 5'-(gamma)triphosphate.
|
| pubmed:affiliation |
Department of Physiology, University of Alberta, Edmonton, Canada.
|
| pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
|