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Activation of GABAergic pathway by hypocretin in the median raphe nucleus (MRN) mediates stress-induced theta rhythm in rats.
- Source :
-
Behavioural brain research [Behav Brain Res] 2012 Jul 15; Vol. 233 (1), pp. 224-31. Date of Electronic Publication: 2012 May 11. - Publication Year :
- 2012
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Abstract
- The frequency of electroencephalograms (EEGs) is predominant in theta rhythm during stress (e.g., footshock) in rats. Median raphe nucleus (MRN) desynchronizes hippocampal theta waves via activation of GABAergic neurons in the medial septum-diagonal band of Broca (MS-DBB), a theta rhythm pacemaker. Increased hypocretin mediates stress responses in addition to the maintenance of wakefulness. Hypocretin receptors are abundant in the MRN, suggesting a possible role of hypocretin in modulating stress-induced theta rhythm. Our results indicated that the intensity of theta waves was enhanced by footshock and that a hypocretin receptor antagonist (TCS1102) suppressed the footshock-induced theta waves. Administration of hypocretin-1 (1 and 10 μg) and hypocretin-2 (10 μg) directly into the MRN simulated the effect of footshock and significantly increased theta waves. Co-administration of GABA(A) receptor antagonist, bicuculline, into the MRN blocked the increase of theta waves induced by hypocretins or footshock. These results suggested that stress enhances the release of hypocretins, activates GABAergic neurons in the MRN, blocks the ability of MRN to desynchronize theta waves, and subsequently increases the intensity of theta rhythm.<br /> (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Subjects :
- Analysis of Variance
Animals
Disease Models, Animal
Electroencephalography
Electroshock adverse effects
GABA Agents pharmacology
Intracellular Signaling Peptides and Proteins antagonists & inhibitors
Male
Neural Pathways drug effects
Neural Pathways physiology
Neuropeptides antagonists & inhibitors
Neuropeptides pharmacology
Neuropeptides therapeutic use
Orexin Receptors
Orexins
Raphe Nuclei drug effects
Rats
Rats, Wistar
Receptors, G-Protein-Coupled therapeutic use
Receptors, Neuropeptide therapeutic use
Signal Transduction drug effects
Stress, Psychological drug therapy
Stress, Psychological etiology
Intracellular Signaling Peptides and Proteins metabolism
Neuropeptides metabolism
Raphe Nuclei physiology
Signal Transduction physiology
Stress, Psychological physiopathology
Theta Rhythm drug effects
gamma-Aminobutyric Acid metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1872-7549
- Volume :
- 233
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Behavioural brain research
- Publication Type :
- Academic Journal
- Accession number :
- 22579972
- Full Text :
- https://doi.org/10.1016/j.bbr.2012.05.002