Effects of serotonin on perifornical-lateral hypothalamic area neurons in rat.
Eur J Neurosci
; 25(1): 201-12, 2007 Jan.
Article
em En
| MEDLINE
| ID: mdl-17241281
ABSTRACT
The hypocretin (HCRT) system of the perifornical-lateral hypothalamic area (PF-LHA) has been implicated in the facilitation of behavioral arousal. HCRT neurons receive serotonergic afferents from the dorsal raphe nucleus. Although in-vitro pharmacological studies suggest that serotonin (5-HT) inhibits HCRT neurons, the in-vivo effects of 5-HT on HCRT neurons in the PF-LHA and associated behavioral changes have not been described. We examined the effects of 5-HT delivered locally into the PF-LHA using reverse microdialysis on its neuronal activity and the consequent sleep-wake changes in rats. First, we quantified Fos expression (Fos-IR) in HCRT and other PF-LHA neurons following unilateral 5-HT perfusion in awake rats. Second, we determined the transient effects of 5-HT perfusion on the extracellular activity of the PF-LHA neurons recorded via microwires placed adjacent to the microdialysis probe. Third, we examined the effects of 5-HT perfusion into the PF-LHA on the sleep-wake profiles of the rats during the lights-off period. Unilateral perfusion of 5-HT into the PF-LHA in awake rats dose-dependently decreased the number of HCRT neurons exhibiting Fos-IR. 5-HT also inhibited the discharge activity of four of five responsive wake-related, putative HCRT neurons. However, unilateral perfusion of 5-HT into the PF-LHA did not produce significant behavioral changes during the 2-h recording period. These results confirm the in-vitro findings that 5-HT exerts inhibitory influences on HCRT neurons but further suggest that the inactivation of a limited number of HCRT neurons by unilateral 5-HT microdialysis may not be sufficient to induce behavioral changes.
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Coleções:
01-internacional
Temas:
Geral
Base de dados:
MEDLINE
Assunto principal:
Serotonina
/
Região Hipotalâmica Lateral
/
Neurônios
Limite:
Animals
Idioma:
En
Revista:
Eur J Neurosci
Assunto da revista:
NEUROLOGIA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Estados Unidos