State-dependent effects of orexins on the serotonergic dorsal raphe neurons in the rat.
Regul Pept
; 126(1-2): 43-7, 2005 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-15620412
ABSTRACT
The serotonergic dorsal raphe (DR) neurons play an important role in sleep-wakefulness regulation. Orexinergic neurons in the lateral hypothalamus densely project to the brainstem sites including the DR. To test the effects of orexins on the serotonergic DR neurons, we applied orexin A (0.1 mM) by pressure to these neurons in unanesthetized and urethane anesthetized rats. Orexin A caused excitation in 10 of 15 neurons under unanesthetized condition. The excitation was characterized by slow onset (0-18 s), long lasting duration (15-150 s) and state-dependency. Orexin A applied during REM sleep or slow wave sleep induced significant excitation while during wakefulness, the similar amount of orexin A did not increase the firing rate any more. In the anesthetized animals, orexin A induced excitation in four of eight neurons. The excitation had slow onset and was long lasting. These results suggest that orexinergic neurons exert excitatory influence on the serotonergic DR neurons to maintain tonic activity of them, thereby participating in regulation of sleep-wakefulness cycles and other functions.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fases do Sono
/
Vigília
/
Neuropeptídeos
/
Núcleos da Rafe
/
Peptídeos e Proteínas de Sinalização Intracelular
/
Neurônios
Limite:
Animals
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article