Linked Life Data

6115322

Source:http://linkedlifedata.com/resource/pubmed/id/6115322

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1981-10-25
pubmed:abstractText
The influence of various calcium antagonists and divalent metal cations on the pressor responses induced by the selective alpha 1-adrenoceptor agonist methoxamine and the selective alpha 2-adrenoceptor stimulating agent B-HT 920 (2-amino-6-allyl-5,6,7,8-tetrahydro-4H-thiazolo[4,5-d]-azepine) was studied in pithed rats. 1. The calcium antagonists verapamil, D 600 and nifedipine, when given intraarterially (i.a.) in doses up to 1 mg/kg did not influence the pressor effects of methoxamine. Only higher amounts of these calcium antagonistic drugs (1 - 3 mg/kg i.a.) somewhat reduced this pressor response. 2. The vasoconstriction due to B-HT 920, as reflected by the increase in diastolic pressure, was markedly inhibited by verapamil, D 600 and nifedipine in a dose-dependent manner. In low doses a parallel displacement to the right was observed, whereas in higher amounts the shift was non-parallel. 3. The divalent cations MN2+, Ni2+ and Co2+ (0.05 - 0.15 mmol/kg i.a.) hardly affected the pressor effect of methoxamine, whereas B-HT 920-induced vasoconstriction was highly sensitive to these metal ions. La3+ and Mg2+ were ineffective. 4. The calcium antagonists verapamil, D 600 and nifedipine displayed only minor affinities for [3H]prazosin (alpha 1) as well as [3H]clonidine (alpha 2) binding sites of rat brain membranes. 5. It is concluded that an influx of extracellular Ca2+ is necessary for the vasoconstriction in vivo initiated by stimulation of vascular postsynaptic alpha 2-adrenoceptors. On the other hand, vasopressor responses to alpha 1-adrenoceptor stimulation are not directly dependent on a transmembrane influx of calcium ions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0028-1298
pubmed:author
pubmed:issnType
Print
pubmed:volume
316
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
288-93
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
Organic and inorganic calcium antagonists reduce vasoconstriction in vivo mediated by postsynaptic alpha 2-adrenoceptors.
pubmed:publicationType
Journal Article