Linked Life Data

10579215

Source:http://linkedlifedata.com/resource/pubmed/id/10579215

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-12-21
pubmed:abstractText
In rat brainstem slices, we investigated the interaction between platelet-activating factor and group I metabotropic glutamate receptors in mediating long-term potentiation within the medial vestibular nuclei. We analysed the N1 field potential wave evoked in the ventral portion of the medial vestibular nuclei by primary vestibular afferent stimulation. The group I metabotropic glutamate receptor antagonist, (R,S)-1-aminoindan-1,5-dicarboxylic acid, prevented long-term potentiation induced by a platelet-activating factor analogue [1-O-hexadecyl-2-O-(methylcarbamyl)-sn-glycero-3-phosphocholine], as well as the full development of potentiation, induced by high-frequency stimulation under the blocking agent for synaptosomal platelet-activating factor receptors (ginkolide B), at drug washout. However, potentiation directly induced by the group I glutamate metabotropic receptor agonist, (R,S)-3,5-dihydroxyphenylglycine, was reduced by ginkolide B. These findings suggest that platelet-activating factor, whether exogenous or released following potentiation induction, exerts its effect through presynaptic group I metabotropic glutamate receptors, mediating the increase of glutamate release. In addition, we found that this mechanism, which led to full potentiation through presynaptic group I metabotropic glutamate receptor activation, was inactivated soon after application of potentiation-inducing stimulus. In fact, the long-lasting block of the platelet-activating factor and metabotropic glutamate receptors prevented the full potentiation development and the induced potentiation progressively declined to null. Moreover, ginkolide B, given when high-frequency-dependent potentiation was established, only reduced it within 5 min after potentiation induction. We conclude that to fully develop vestibular long-term potentiation requires presynaptic events. Platelet-activating factor, released after the activation of postsynaptic mechanisms which induce potentiation, is necessary for coupling postsynaptic and presynaptic phenomena, through the activation of group I metabotropic glutamate receptors, and its action lasts only for a short period. If this coupling does not occur, a full and long-lasting potentiation cannot develop.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:volume
94
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
549-59
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Platelet-activating factor and group I metabotropic glutamate receptors interact for full development and maintenance of long-term potentiation in the rat medial vestibular nuclei.
pubmed:affiliation
Institute of Human Physiology, University of Perugia, Italy. isfisuma@unipg.it
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't