Linked Life Data

17959799

Source:http://linkedlifedata.com/resource/pubmed/id/17959799

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
43
pubmed:dateCreated
2007-10-25
pubmed:abstractText
The effect of group I metabotropic glutamate receptor (mGluR1 and mGluR5) activation on identified melanin-concentrating hormone (MCH) neurons was studied using patch-clamp recording in hypothalamic slices from green fluorescent protein-expressing transgenic mice. S-3,5-dihydroxyphenylglycine (DHPG), a selective group I mGluR agonist, depolarized MCH cells and increased spike frequency. The mGluR-mediated depolarization was not blocked with tetrodotoxin but was significantly reduced by replacement of extracellular Na+ with Tris, by Ni2+ or the Na+/Ca2+ exchanger blocker KB-R7943, or with BAPTA in the pipette, consistent with a mechanism based on activation of the Na+/Ca2+ exchanger. DHPG also decreased potassium currents. DHPG-induced depolarization was reduced by either mGluR1 or mGluR5 antagonists, suggesting involvement of both receptor subtypes. DHPG-induced depolarization desensitized; blockade of mGluR1 prevented the desensitization. Group I mGluR activation enhanced NMDA-evoked currents; this enhancement was remarkably long lasting and could be blocked by protein kinase A or C blockers. DHPG potentiated electrically evoked NMDA receptor-mediated postsynaptic currents, and mGluR5 antagonists blocked this action. Group I mGluRs increased spontaneous EPSCs in MCH neurons, possibly by stimulation of nearby mGluR-expressing hypocretin neurons. We found no tonic activation of mGluRs. However, electrical stimulation produced a slow inward current, which could be blocked by group I mGluR antagonists, suggesting high, but not low, levels of synaptically released glutamate activated mGluRs. Together, group I mGluRs increase MCH neuron activity by multiple presynaptic and postsynaptic mechanisms, suggesting mGluRs may therefore play a role in hypothalamic signaling relating to MCH neuron modulation of food intake and energy metabolism.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
24
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11560-72
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Rapid direct excitation and long-lasting enhancement of NMDA response by group I metabotropic glutamate receptor activation of hypothalamic melanin-concentrating hormone neurons.
pubmed:affiliation
Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, N.I.H., Extramural