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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1996-3-4
pubmed:abstractText
Flesinoxan is a high affinity and selective 5-hydroxytryptamine1A (5-HT1A) ligand which, unlike the 5-HT1A agonists of the azapirone class, does not generate 1-(2-pyrimidinyl)piperazine, an alpha 2-adrenoreceptor antagonist. In view of potential antidepressant effects of flesinoxan, this study was undertaken to characterize its 5-HT1A properties in the rat brain using in vivo electrophysiology and hypothermia paradigms. The suppressant effect of microiontophoretic applications of flesinoxan on the firing activity of CA3 pyramidal neurons was blocked by concomitant application of the 5-HT1A antagonist BMY 7378. Compared to gepirone, the efficacy of flesinoxan to suppress the firing activity of CA3 pyramidal neurons was significantly greater. While the coapplication of flesinoxan antagonized the suppressant effect of 5-HT on CA3 pyramidal neurons, it failed to do so on dorsal raphe 5-HT neurons, indicating that flesinoxan acts as a partial agonist at postsynaptic and as a full agonist at presynaptic 5-HT1A receptors. The capacity of flesinoxan to antagonize the effect of 5-HT on CA3 pyramidal neurons was similar to that of 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) and significantly greater than that of gepirone. The intravenous administration of flesinoxan suppressed the firing activity of both CA3 pyramidal neurons and dorsal raphe 5-HT neurons. However, when compared to 8-OH-DPAT, significantly higher doses of flesinoxan were required. The acute brain penetration of [3H]flesinoxan and [3H]8-OH-DPAT was, therefore, determined. Nine minutes after intravenous administration, [3H]8-OH-DPAT reached significantly greater brain concentration than [3H]flesinoxan. Subcutaneous administration of flesinoxan and 8-OH-DPAT produced a dose-dependent hypothermia. The flesinoxan-induced hypothermia was significantly attenuated by prior administration of the non-selective 5-HT1A antagonist pindolol and the 5-HT1/2 antagonist methysergide. Similar degrees of hypothermia were achieved with 3 mg/kg of flesinoxan and 0.5 mg/kg of 8-OH-DPAT. The maximal effect of flesinoxan occurred 30 min later than that of 8-OH-DPAT and faded more slowly. The 5-HT1A properties of flesinoxan suggest that it may be an effective anxiolytic/antidepressant agent.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0028-3908
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1311-26
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Characterization of 5-hydroxytryptamine1A properties of flesinoxan: in vivo electrophysiology and hypothermia study.
pubmed:affiliation
Department of Psychiatry, McGill University, Montréal, Québec, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't