Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1994-10-19
pubmed:abstractText
The alpha 2-adrenoceptors located prejunctionally on the postganglionic neurons that innervate the smooth muscle of the prostatic portion of the rat vas deferens were examined. For this purpose, three imidazolidine derivatives (structurally related to clonidine) were studied for their effects on twitch contractions elicited by electrical field stimulation of this tissue. In this study, operational model-fitting and the nested hyperbolic method were used to analyse the effects of irreversible receptor alkylation by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) on the alpha 2-adrenoceptor-mediated effects of clonidine (2-[2,6-dichlorophenylimino]imidazolidine) in stimulated vas deferens. The operational model provided an estimate of KA for clonidine which was not significantly different from the estimate obtained by using the nested hyperbolic method (null approach). The data indicate a large receptor reserve at prejunctional alpha 2-adrenoceptors for clonidine. The estimates of apparent affinity for St-587 (2-[2-chloro-5-trifluoromethylphenylimino]imidazolidine) and St-591 (2-[2-chloro-5-methylphenylimino]imidazolidine) did not depend on the method of calculation as the 'null' method and the 'operational' method gave similar answers. Further, estimates of the ratio of tau values for these partial agonists with respect to clonidine were numerically the same as those of their relative efficacies. Therefore, no limitations in the ability of the operational model to fit experimental data and provide reproducible estimates of affinity and efficacy have been revealed for agonists acting at prejunctional alpha 2-adrenoceptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
229-38
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Analysis of agonism at functional prejunctional alpha 2-adrenoceptors of rat vas deferens using operational and null approaches.
pubmed:affiliation
Departament de Farmacologia i Psiquiatria, Facultat de Medicina, Universitat Autònoma de Barcelona, Spain.
pubmed:publicationType
Journal Article, In Vitro