Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
|
| pubmed:dateCreated |
1996-12-23
|
| pubmed:abstractText |
The subtype determination of auto- and hetero-alpha 2-adrenoceptors modulating the synthesis of noradrenaline (NA) and serotonin (5-HT), respectively, was assessed using the accumulation of 3,4-dihydroxyphenylalanine (dopa) and 5-hydroxytryptophan (5-HTP) after decarboxylase inhibition as a measure of the rate of tyrosine and tryptophan hydroxylation in the rat brain in vivo. In the cerebral cortex and hippocampus, Org 3770 (non-selective alpha 2-adrenoceptor antagonist, 0.5-10 mg/kg, i.p.) increased (43%-58%) and clonidine (non-selective alpha 2-adrenoceptor agonist, 1 mg/kg) decreased (37%-49%) the synthesis of dopa. Also the antagonist ARC 239 (alpha 2B/C selective, 5-40 mg/kg) increased the synthesis of dopa in cortex (39%-46%) and hippocampus (17%-85%). In contrast, the antagonist BRL 44408 (alpha 2D selective, 1-10 mg/kg) did not increase the synthesis of dopa in cortex, and increased it modestly in hippocampus only. The agonist guanoxabenz (alpha 2B/C selective, 0.03-3 mg/kg) decreased the synthesis of dopa in both brain regions (20%-65%), whereas the agonist oxymetazoline (alpha 2D selective, 0.1-3 mg/kg) failed to do so. These results indicated that the alpha 2-autoreceptors that modulate the synthesis of dopa/NA are probably associated with the alpha 2B/C-subtypes. In cortex and hippocampus, clonidine decreased (35%-53%) the synthesis of 5-HTP but Org 3770 failed to induce the opposite effect (except the 2 mg/kg dose in cortex). BRL 44408 markedly increased the synthesis of 5-HTP in cortex (113%-148%) but not in hippocampus. Similarly, also ARC239 increased the formation of 5-HTP in cortex (36%-48%) but not in hippocampus, where it was decreased (30%-55%). Oxymetazoline decreased the synthesis of 5-HTP in hippocampus (28%-30%) but failed to do so in cortex. Guanoxabenz in the low dose range (0.03-0.3 mg/kg) did not decrease the synthesis of 5-HTP in any brain region. These results indicated that the alpha 2-heteroreceptors that modulate the synthesis of 5-HTP/5-HT may well be different from the proposed alpha 2B/C-autoreceptors modulating the synthesis of dopa/NA. These alpha 2-heteroreceptors appear to be associated with the alpha 2D-subtype.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/AR-C239,
http://linkedlifedata.com/resource/pubmed/chemical/Adrenergic alpha-Agonists,
http://linkedlifedata.com/resource/pubmed/chemical/Adrenergic alpha-Antagonists,
http://linkedlifedata.com/resource/pubmed/chemical/BRL 44408,
http://linkedlifedata.com/resource/pubmed/chemical/Dihydroxyphenylalanine,
http://linkedlifedata.com/resource/pubmed/chemical/EEDQ,
http://linkedlifedata.com/resource/pubmed/chemical/Histamine H1 Antagonists,
http://linkedlifedata.com/resource/pubmed/chemical/Imidazoles,
http://linkedlifedata.com/resource/pubmed/chemical/Indoles,
http://linkedlifedata.com/resource/pubmed/chemical/Isoindoles,
http://linkedlifedata.com/resource/pubmed/chemical/Isoquinolines,
http://linkedlifedata.com/resource/pubmed/chemical/Mianserin,
http://linkedlifedata.com/resource/pubmed/chemical/Norepinephrine,
http://linkedlifedata.com/resource/pubmed/chemical/Piperazines,
http://linkedlifedata.com/resource/pubmed/chemical/Quinolines,
http://linkedlifedata.com/resource/pubmed/chemical/Serotonin,
http://linkedlifedata.com/resource/pubmed/chemical/Tryptophan Hydroxylase,
http://linkedlifedata.com/resource/pubmed/chemical/Tyrosine 3-Monooxygenase,
http://linkedlifedata.com/resource/pubmed/chemical/mirtazapine
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Mar
|
| pubmed:issn |
0028-1298
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
353
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
391-9
|
| pubmed:dateRevised |
2007-11-15
|
| pubmed:meshHeading |
pubmed-meshheading:8935705-Adrenergic alpha-Agonists,
pubmed-meshheading:8935705-Adrenergic alpha-Antagonists,
pubmed-meshheading:8935705-Analysis of Variance,
pubmed-meshheading:8935705-Animals,
pubmed-meshheading:8935705-Brain,
pubmed-meshheading:8935705-Cerebral Cortex,
pubmed-meshheading:8935705-Dihydroxyphenylalanine,
pubmed-meshheading:8935705-Dose-Response Relationship, Drug,
pubmed-meshheading:8935705-Hippocampus,
pubmed-meshheading:8935705-Histamine H1 Antagonists,
pubmed-meshheading:8935705-Imidazoles,
pubmed-meshheading:8935705-Indoles,
pubmed-meshheading:8935705-Isoindoles,
pubmed-meshheading:8935705-Isoquinolines,
pubmed-meshheading:8935705-Male,
pubmed-meshheading:8935705-Mianserin,
pubmed-meshheading:8935705-Norepinephrine,
pubmed-meshheading:8935705-Piperazines,
pubmed-meshheading:8935705-Quinolines,
pubmed-meshheading:8935705-Rats,
pubmed-meshheading:8935705-Rats, Sprague-Dawley,
pubmed-meshheading:8935705-Serotonin,
pubmed-meshheading:8935705-Tryptophan Hydroxylase,
pubmed-meshheading:8935705-Tyrosine 3-Monooxygenase
|
| pubmed:year |
1996
|
| pubmed:articleTitle |
Alpha 2-autoreceptors and alpha 2-heteroreceptors modulating tyrosine and tryptophan hydroxylase activity in the rat brain in vivo: an investigation into the alpha 2-adrenoceptor subtypes.
|
| pubmed:affiliation |
Departament de Biologia Fonamental i Ciències de la Salut, Universitat de les Illes Balears, Palma de Mallorca, Spain.
|
| pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, Non-U.S. Gov't
|