Linked Life Data

139193

Source:http://linkedlifedata.com/resource/pubmed/id/139193

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1977-5-20
pubmed:abstractText
Presynaptic inhibition of the extensor (quadriceps, QUAD) monosynaptic reflex (MSR) in unanaesthetized decerebrate cats was antagonized by imipramine hydrochloride (2-5 mg/kg), 5-hydroxytryptophan (75 mg/kg) and a specific 5-hydroxytryptamine (5-HT) neuronal uptake blocker, fluoxetine hydrochloride (Lilly 110140, 0.25-6 mg/kg). These effects of imipramine and fluoxetine were partially reversed by the 5-HT antagonist, cyproheptadine hydrochloride (5 mg/kg), and completely reversed by the application of a thoracic cold block which prevents supraspinal inputs to the caudal spinal cord. Imipramine, however, failed to antagonize this inhibition in animals pretreated with either DL-p-chlorophenylalanine (p-CPA, 300 mg/kg i.p. for 2 consecutive days) or DL-a-methyl-p-tyrosine methyl ester hydrochloride (a-MPt, 125 mg/kg i.p. 16 and 4 h prior to the experiment). Cyproheptadine (2.5--5 mg/kg); phenoxybenzamine hydrochloride (2.5-5 mg/kg) and a cold block enhanced the inhibition of this extensor MSR but a cold block failed to alter the inhibition in animals pretreated with p-CPA or a-MPT. Presynaptic inhibition of the flexor (posterior biceps-semitendinosus, PBST) MSR was however not blocked by imipramine, fluoxetine or a cold block nor enhanced by cyproheptadine or phenoxybenzamine. The effects of the drugs tested and a cold block on the excitability of the QUAD group Ia afferents were reciprocal to those on the MSR during presynaptic inhibition. The results of this study indicate that descending tonically active systems (1) involving 5-HT and noradrenaline, antagonize presynaptic inhibition of the QUAD but not the PBST-MSR, (2) decrease the excitability of the QUAD Ia afferents and (3) increase the excitability of QUAD motoneurones.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
124
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
109-20
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Tonic inhibitory influence of a supraspinal monoaminergic system on presynaptic inhibition of an extensor monosynaptic reflex.
pubmed:publicationType
Journal Article