Linked Life Data

17475795

Source:http://linkedlifedata.com/resource/pubmed/id/17475795

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2007-5-3
pubmed:abstractText
Cannabinoids modulate energy homeostasis and decrease cognitive arousal, possibly by acting on hypothalamic neurons including those that synthesize melanin-concentrating hormone (MCH) or hypocretin/orexin. Using patch-clamp recordings, we compared the actions of cannabinoid agonists and antagonists on identified MCH or hypocretin neurons in green fluorescent protein-expressing transgenic mice. The cannabinoid type-1 receptor (CB1R) agonist R-(+)-[2,3-dihydro-5-methyl-3-(4-morpho linylmethyl)pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl]-1-naphthalenylmethanone mesylate (WIN55,212,2) depolarized MCH cells and increased spike frequency; in contrast, WIN55,212,2 hyperpolarized and reduced spontaneous firing of the neighboring hypocretin cells, both results consistent with reduced activity seen with intracerebral cannabinoid infusions. These effects were prevented by AM251 [N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide], a CB1R antagonist, and by tetrodotoxin, suggesting no postsynaptic effect on either neuron type. In MCH cells, depolarizing WIN55,212,2 actions were abolished by the GABA(A) receptor antagonist bicuculline, suggesting that the CB1R-mediated depolarization was attributable to reduced synaptic GABA release. WIN55,212,2 decreased spontaneous IPSCs, reduced the frequency but not amplitude of miniature IPSCs, and reduced electrically evoked synaptic currents in MCH cells. Glutamate microdrop experiments suggest that WIN55,212,2 acted on axons arising from lateral hypothalamus local inhibitory cells that innervate MCH neurons. In hypocretin neurons, the reduced spike frequency induced by WIN55,212,2 was attributable to presynaptic attenuation of glutamate release; CB1R agonists depressed spontaneous and evoked glutamatergic currents and reduced the frequency of miniature EPSCs. Cannabinoid actions on hypocretin neurons were abolished by ionotropic glutamate receptor antagonists. Together, these results show that cannabinoids have opposite effects on MCH and hypocretin neurons. These opposing actions could help explain the increase in feeding and reduction in arousal induced by cannabinoids.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Benzoxazines, http://linkedlifedata.com/resource/pubmed/chemical/Cannabinoids, http://linkedlifedata.com/resource/pubmed/chemical/Hypothalamic Hormones, http://linkedlifedata.com/resource/pubmed/chemical/Intracellular Signaling Peptides..., http://linkedlifedata.com/resource/pubmed/chemical/Melanins, http://linkedlifedata.com/resource/pubmed/chemical/Morpholines, http://linkedlifedata.com/resource/pubmed/chemical/Naphthalenes, http://linkedlifedata.com/resource/pubmed/chemical/Neuropeptides, http://linkedlifedata.com/resource/pubmed/chemical/Pituitary Hormones, http://linkedlifedata.com/resource/pubmed/chemical/Win 55212-2, http://linkedlifedata.com/resource/pubmed/chemical/melanin-concentrating hormone, http://linkedlifedata.com/resource/pubmed/chemical/orexins
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
2
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4870-81
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Cannabinoids excite hypothalamic melanin-concentrating hormone but inhibit hypocretin/orexin neurons: implications for cannabinoid actions on food intake and cognitive arousal.
pubmed:affiliation
Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural