Linked Life Data

241844

Source:http://linkedlifedata.com/resource/pubmed/id/241844

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1976-1-30
pubmed:abstractText
For eliciting contraction of rabbit aorta, the relative potency of agonists in terms of negative log molar ED50 were: oxymetazoline (8.4) greater than naphazoline (7.95) greater than phenylephrine (7.31) greater than tetrahydrozoline (6.5) greater than tolazoline (5.80). None of the imidazolines, however, produced maximal effects equal to that of phenylephrine. All agonists were directly acting agents. The interactions between oxymetazoline and phentolamine or tolazoline and phentolamine were competitive with pA2 values of 8.1 and 8.0, respectively. Phentolamine with tetrahydrozoline, naphazoline or phenylephrine produced nearly equal KB values. Thus, all the agonists and alpha adrenoceptor blockers must act at a common site in rabbit aorta. As expected, the contraction of rabbit aorta produced by an imidazole histamine was competitively antagonized by the histamine 1 antagonist, chlorpheniramine (K B 7.6 X 10(-9) M). The antagonist failed to block the contraction produced by the imidazolines studied. On guinea-pig aorta, the relative potency of the agonists varied greatly. On guinea-pig atria, tetrahydrozoline and tolazoline produced positive chronotropic effects which were not influenced by reserpine and cocaine treatment, or treatment with a beta adrenoceptor blocker, propranolol. The histamine 2 receptor antagonist, metiamide, however, selectively blocked the cardiac effects. It is concluded that oxymetazoline and naphazoline do not activate histamine 1 or histamine 2 receptors or beta adrenoceptors. Thus, the drugs are highly specific alpha adrenoceptor stimulants. On the other hand, tetrahydrozoline and tolazoline interact with histamine 2 receptors and with alpha adrenoceptors, but not with histamine 1 receptors or with beta adrenoceptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
195
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
362-71
pubmed:dateRevised
2009-10-27
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Alpha adrenergic and histaminergic effects of tolazoline-like imidazolines.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.