Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1990-6-28
pubmed:abstractText
The role of alpha 1-, alpha 2- and beta-adrenoceptors in vasoconstrictor responses to sympathetic nerve stimulation was investigated in perfused proximal segments of rat tail artery by using selective blocking drugs. Prazosin (1 nM) markedly reduced the responses but idazoxan (100 nM) did not, and propranolol (1 microM) significantly enhanced them, indicating that the vasoconstriction was due to activation of alpha 1-adrenoceptors and that it was partly counteracted by a vasodilator component due to activation of beta-adrenoceptors. In the presence of propranolol, idazoxan or reduction of the concentration of Ca2+ in the perfusing solution from 2.5 to 0.63 mM significantly reduced responses to sympathetic nerve stimulation, indicating that a component of the vasoconstrictor response was due to activation of alpha 2-adrenoceptors. Forskolin, which increases cyclic AMP levels independently of beta-adrenoceptors, reduced responses to sympathetic nerve stimulation to a greater extent in the presence than in the absence of propranolol and this effect was additive with that of prazosin but not idazoxan. It is concluded that activation of beta-adrenoceptors inhibits the component of responses to sympathetic nerve stimulation due to activation of alpha 2-adrenoceptors because of an inhibitory effect of cyclic AMP on Ca2+ channels linked to alpha 2-adrenoceptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
177
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
35-41
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:1971218-Adenylate Cyclase, pubmed-meshheading:1971218-Adrenergic beta-Antagonists, pubmed-meshheading:1971218-Animals, pubmed-meshheading:1971218-Calcium, pubmed-meshheading:1971218-Dioxanes, pubmed-meshheading:1971218-Electric Stimulation, pubmed-meshheading:1971218-Forskolin, pubmed-meshheading:1971218-Idazoxan, pubmed-meshheading:1971218-Male, pubmed-meshheading:1971218-Muscle, Smooth, Vascular, pubmed-meshheading:1971218-Neurotransmitter Agents, pubmed-meshheading:1971218-Prazosin, pubmed-meshheading:1971218-Propranolol, pubmed-meshheading:1971218-Rats, pubmed-meshheading:1971218-Rats, Inbred Strains, pubmed-meshheading:1971218-Receptors, Adrenergic, alpha, pubmed-meshheading:1971218-Receptors, Adrenergic, beta, pubmed-meshheading:1971218-Regional Blood Flow, pubmed-meshheading:1971218-Sympathetic Nervous System, pubmed-meshheading:1971218-Tail, pubmed-meshheading:1971218-Vasoconstriction
pubmed:year
1990
pubmed:articleTitle
Vasoconstrictor responses of rat tail artery to sympathetic nerve stimulation contain a component due to activation of postjunctional beta- or alpha 2-adrenoceptors.
pubmed:affiliation
Department of Pharmacology, University of Melbourne, Victoria, Australia.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't