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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1979-7-28
pubmed:abstractText
The effect of various catecholamines and alpha-mimetics, given by microinjection in the A2-region of the nucleus tractus solitarii (NTS), on blood pressure was investigated in anesthetized male rats. A dose-dependent decrease of blood pressure and heart rate was induced by adrenaline as the most effective drug, followed by noradrenaline, dopamine, alpha-methylnoradrenaline and octopamine. Ablation of the rostral or caudal part of the NTS, or removal of the area postrema did not diminish the effect of alpha-methylnoradrenaline. Higher doses of noradrenaline and alpha-methylnoradrenaline caused an initial rise of blood pressure, while the blood pressure lowering effect of noradrenaline was diminished, and that of alpha-methylnoradrenaline and dopamine delayed. Isoprenaline and the (+)-stereoisomers of noradrenaline and alpha-methylnoradrenaline were ineffective. The hypotensive effect of dopamine was not prevented by systemic injection of the dopamine beta-hydroxylase inhibitor FLA 63. Prior application of haloperidol, yohimbine and phentolamine antagonized the hypotensive response to dopamine and alpha-methylnoradrenaline. Application of peripherally effective alpha-mimetics into the A2-region had no or little effect, while high doses increased blood pressure. Tyramine and clonidine caused some decrease of blood pressure. Clonidine also decreased blood pressure when it was applied in the area of the locus coeruleus. Application of isoprenaline in the locus coeruleus also decreased blood pressure while in contrast adrenaline, noradrenaline, dopamine and alpha-methylnoradrenaline increased blood pressure. The present data suggest that the catecholaminergic receptors in the A2-region of the NTS differ from the classic vascular alpha-receptor and that the NTS also may contain structures which can antagonize the decrease in blood pressure.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
55
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
43-56
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1979
pubmed:articleTitle
Effect of catecholamine-receptor stimulating agents on blood pressure after local application in the nucleus tractus solitarii of the medulla oblongata.
pubmed:publicationType
Journal Article