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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1977-1-25
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pubmed:abstractText |
Recurrent inhibition of the extensor (quadriceps) monosynaptic reflex (MSR) was antagonized by a 5-hydroxytryptamine (5-HT) precursor, 5-hydroxytryptophan (5-HTP, 75 mg/kg), and a specific 5-HT neuronal uptake blocker, fluoxetine-HC1 (Lilly 110140, 0.25-6 mg/kg), in unanaesthetized decerebrate cats. This inhibition of the flexor (posterior biceps-semitendinosus) MSR was not altered by fluoxetine. Cyproheptadine-HC1 (5 mg/kg) partially reversed the above blocking actions of 5-HTP and fluoxetine and a thoracic "cold block", which eliminates supraspinal inputs to the caudal spinal cord, also eliminated the blockade by fluoxetine on recurrent inhibition. Cyproheptadine (2.5-5 mg/kg) or phenoxybenzamine-HC1 (2.5-5 mg/kg), administered alone, enhanced recurrent inhibition of the extensor but not of the flexor MSR. Since a "cold block" increased recurrent inhibition of the extensor reflex in control animals but failed to alter the inhibition in animals pretreated with either DL-p-chlorophenylalanine (300 mg/kg i.p. for 2 consecutive days) or DL-a-methyl-p-tyrosine methyl ester-HC1 (125 mg/kg i.p. 16 and 4 h prior to experiment), the monoaminergic system would appear to be tonically active. In addition the neuronal uptake blocker, imipramine-HC1 (0.125-4 mg/kg), was more potent in antagonizing recurrent inhibition when injected intra-arterially to the spinal cord than when administered intra-arterially to the brain stem or intravenously, indicating that this agent acts in the spinal cord to block the inhibition. These results support our previous proposal (ref. 18) that a supraspinal system involving 5-HT and noradrenaline antagonizes recurrent inhibition of the quadriceps MSR. This monoaminergic system is tonically active with the 5-HT nerve terminals located in the spinal cord.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0006-8993
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
19
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pubmed:volume |
117
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
69-76
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pubmed:dateRevised |
2003-11-14
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pubmed:meshHeading |
pubmed-meshheading:1086701-5-Hydroxytryptophan,
pubmed-meshheading:1086701-Animals,
pubmed-meshheading:1086701-Cats,
pubmed-meshheading:1086701-Imipramine,
pubmed-meshheading:1086701-Neural Inhibition,
pubmed-meshheading:1086701-Receptors, Drug,
pubmed-meshheading:1086701-Reflex, Monosynaptic,
pubmed-meshheading:1086701-Serotonin Antagonists
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pubmed:year |
1976
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pubmed:articleTitle |
Tonic inhibitory influence of a supraspinal monoaminergic system on recurrent inhibition of an extensor monosynaptic reflex.
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pubmed:publicationType |
Journal Article
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