Linked Life Data

2877400

Source:http://linkedlifedata.com/resource/pubmed/id/2877400

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1986-12-12
pubmed:abstractText
The effects of several alpha-adrenoceptor antagonists have been examined on tritium release elicited by electrical stimulation from isolated perfused SHR tail artery preparations prelabelled with 3H-noradrenaline (3H-NA). Phentolamine and yohimbine potently facilitated the stimulation evoked release of tritium at low frequencies of stimulation, but the alpha 2-adrenoceptor antagonist idazoxan was only weakly active at 1 mumol/l, despite antagonising the clonidine-evoked inhibition of 3H-release at a lower concentration of 0.1 mumol/l. The alpha 1-adrenoceptor antagonists prazosin and corynanthine also increased stimulation evoked tritium release in this preparation, suggesting the presence of prejunctional alpha 1-adrenoceptors. Furthermore, the alpha 1-adrenoceptor agonist methoxamine (3 mumol/l) caused a significant inhibition of tritium-evoked release, an effect which was blocked by prazosin (10 nmol/l). When alpha 1-adrenoceptors were blocked in the presence of prazosin, idazoxan (0.1 mumol/l) produced a significant facilitatory effect on the electrically-evoked release of 3H-transmitter. On the other hand, when alpha 2-adrenoceptors were blocked in the presence of yohimbine, exposure to idazoxan (0.1 mumol/l) reduced significantly the stimulation-evoked release of tritium elicited by electrical stimulation. The results indicate that in the SHR tail arteries, idazoxan has a partial agonist inhibitory activity on transmitter release, which can mask the facilitatory effects due to blockade of presynaptic alpha 2-adrenoceptors. The inhibitory effects of idazoxan appear to involve presynaptic alpha 1-adrenoceptors, which when stimulated, reduce 3H-NA release in SHR tail arteries.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0028-1298
pubmed:author
pubmed:issnType
Print
pubmed:volume
333
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
354-61
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Possible involvement of presynaptic alpha 1-adrenoceptors in the effects of idazoxan and prazosin on 3H-noradrenaline release from tail arteries of SHR.
pubmed:publicationType
Journal Article