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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
11
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pubmed:dateCreated |
1991-5-23
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pubmed:abstractText |
The effects of alpha 1- and alpha 2-adrenoceptor agonists on smooth muscle tone and on cholinergic excitatory and non-adrenergic, non-cholinergic inhibitory responses to field stimulation have been investigated in the rat gastric fundus in-vitro. None of the alpha-adrenoceptor agonists tested, noradrenaline, phenylephrine, cirazoline, guanoxabenz or UK-14,304 showed any contractile effects at concentrations up to 30 microM. In preparations where tone was raised by barium (0.5-2 mM), the mixed alpha 1- and alpha 2-adrenoceptor agonist noradrenaline (0.01-10 microM), and the selective alpha 1-adrenoceptor agonists cirazoline (0.01-10 microM) and phenylephrine (0.01-10 microM) produced concentration-dependent relaxations which were antagonized by the alpha 1-adrenoceptor antagonist prazosin (0.01-1.0 microM). The selective alpha 2-adrenoceptor agonists UK-14,304 (0.03-30 microM) and guanoxabenz (0.03-30 microM), had no relaxant effects in raised tone. UK-14,304 (0.03-1.0 microM) produced a concentration-dependent inhibition of cholinergic nerve-induced responses which was antagonized by the alpha 2-adrenoceptor antagonist idazoxan (0.03-1.0 microM) but not by prazosin (0.03-1.0 microM). Noradrenaline (0.03-1.0 microM) also produced an inhibition of cholinergic nerve-induced responses which was antagonized by idazoxan (0.03-1.0 microM). A small component of the noradrenaline inhibitory effects was antagonized by prazosin (10%). Cirazoline (0.03-1.0 microM) produced a small inhibition of cholinergic nerve-induced responses which was antagonized by prazosin (0.03-1.0 microM). The prazosin-sensitive components of the inhibitory effects of noradrenaline and cirazoline occurred at concentrations which also produced post-junctional relaxation.(ABSTRACT TRUNCATED AT 250 WORDS)
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adrenergic alpha-Agonists,
http://linkedlifedata.com/resource/pubmed/chemical/Adrenergic alpha-Antagonists,
http://linkedlifedata.com/resource/pubmed/chemical/Dioxanes,
http://linkedlifedata.com/resource/pubmed/chemical/Idazoxan,
http://linkedlifedata.com/resource/pubmed/chemical/Prazosin
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0022-3573
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
42
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
752-7
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pubmed:dateRevised |
2003-11-14
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pubmed:meshHeading |
pubmed-meshheading:1982297-Adrenergic alpha-Agonists,
pubmed-meshheading:1982297-Adrenergic alpha-Antagonists,
pubmed-meshheading:1982297-Animals,
pubmed-meshheading:1982297-Cholinergic Fibers,
pubmed-meshheading:1982297-Dioxanes,
pubmed-meshheading:1982297-Electric Stimulation,
pubmed-meshheading:1982297-Gastric Fundus,
pubmed-meshheading:1982297-Idazoxan,
pubmed-meshheading:1982297-Male,
pubmed-meshheading:1982297-Muscle, Smooth,
pubmed-meshheading:1982297-Muscle Contraction,
pubmed-meshheading:1982297-Prazosin,
pubmed-meshheading:1982297-Rats,
pubmed-meshheading:1982297-Rats, Inbred Strains
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pubmed:year |
1990
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pubmed:articleTitle |
Pre- and post-junctional alpha-adrenoceptor-mediated responses in the rat gastric fundus in-vitro.
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pubmed:affiliation |
Department of Biological Sciences, Glasgow College, UK.
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pubmed:publicationType |
Journal Article
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