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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1980-12-18
pubmed:abstractText
The responsiveness of hippocampal CA3 pyramidal neurons to microiontophoretic applications of serotonin (5-HT), norepinephrine (NE), gamma-aminobutyric acid (GABA) and isoproterenol (ISO) was assessed in rats following 5,7-dihydroxy-tryptamine (5,7-DHT) and 6-hydroxydopamine (6-OHDA) pretreatments and bilateral locus coeruleus lesions. The intraventricular administration of 200 micrograms (free base) of 5,7-DHT and of 6-OHDA produced 89% and 93% decreases of 5-HT and NE respectively. None of these pretreatments modified the inital responsiveness to, or recovery from iontophoretic application of 5-HT. In 6-OHDA pretreated and locus-lesioned rats, the initial effectiveness of NE was not altered but its effect was markedly prolonged. However, there was no such prolongation of the effect of ISO which is not a substrate for the high affinity NE reuptake. The effect of GABA was not affected by these pretreatments. Acute pharmacological blockade of the NE reuptake with desipramine (5 mg/kg, i.p.) similarly induced a prolongation of the effect of iontophoretically applied NE, while fluoxetine (10 mg/kg, i.p.) a 5-HT reuptake blocker, failed to alter the recovery of pyramidal cells from iontophoretic application of 5-HT. It is concluded that 5-HT denervation induces neither pre- nor postsynaptic types of supersensitivity in hippocampal pyramidal cells, contrasting with the previously shown supersensitivity of ventral lateral geniculate and amygdaloid neurons following 5-HT denervation. NE denervation fails to induce a postsynaptic type of supersensitivity but leads to a marked prolongation of the response to NE indicative of a presynaptic mechanism. These results underscore the necessity for regional studies of neurotransmitters and drug action.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
200
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
363-76
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1980
pubmed:articleTitle
Monoaminergic denervation of the rat hippocampus: microiontophoretic studies on pre- and postsynaptic supersensitivity to norepinephrine and serotonin.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.