Linked Life Data

19357273

Source:http://linkedlifedata.com/resource/pubmed/id/19357273

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
2009-4-9
pubmed:abstractText
The histaminergic tuberomamillary nucleus (TMN) controls arousal and attention, and the firing of TMN neurons is state-dependent, active during waking, silent during sleep. Thyrotropin-releasing hormone (TRH) promotes arousal and combats sleepiness associated with narcolepsy. Single-cell reverse-transcription-PCR demonstrated variable expression of the two known TRH receptors in the majority of TMN neurons. TRH increased the firing rate of most (ca 70%) TMN neurons. This excitation was abolished by the TRH receptor antagonist chlordiazepoxide (CDZ; 50 mum). In the presence of tetrodotoxin (TTX), TRH depolarized TMN neurons without obvious change of their input resistance. This effect reversed at the potential typical for nonselective cation channels. The potassium channel blockers barium and cesium did not influence the TRH-induced depolarization. TRH effects were antagonized by inhibitors of the Na(+)/Ca(2+) exchanger, KB-R7943 and benzamil. The frequency of GABAergic spontaneous IPSCs was either increased (TTX-insensitive) or decreased [TTX-sensitive spontaneous IPSCs (sIPSCs)] by TRH, indicating a heterogeneous modulation of GABAergic inputs by TRH. Facilitation but not depression of sIPSC frequency by TRH was missing in the presence of the kappa-opioid receptor antagonist nor-binaltorphimine. Montirelin (TRH analog, 1 mg/kg, i.p.) induced waking in wild-type mice but not in histidine decarboxylase knock-out mice lacking histamine. Inhibition of histamine synthesis by (S)-alpha-fluoromethylhistidine blocked the arousal effect of montirelin in wild-type mice. We conclude that direct receptor-mediated excitation of rodent TMN neurons by TRH demands activation of nonselective cation channels as well as electrogenic Na(+)/Ca(2+) exchange. Our findings indicate a key role of the brain histamine system in TRH-induced arousal.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1529-2401
pubmed:author
pubmed:issnType
Electronic
pubmed:day
8
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4471-83
pubmed:dateRevised
2011-10-24
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Excitation of histaminergic tuberomamillary neurons by thyrotropin-releasing hormone.
pubmed:affiliation
Department of Neurophysiology, Heinrich Heine University, Duesseldorf, Germany.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't