We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Effects of serotonin on perifornical-lateral hypothalamic area neurons in rat.
- Authors
Kumar, Sunil; Szymusiak, Ronald; Bashir, Tariq; Rai, Seema; McGinty, Dennis; Alam, Md. Noor
- 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.
- Subjects
SEROTONIN; OREXINS; MELANINS; AROUSAL (Physiology); NEURONS; HYPOTHALAMUS
- Publication
European Journal of Neuroscience, 2007, Vol 25, Issue 1, p201
- ISSN
0953-816X
- Publication type
Article
- DOI
10.1111/j.1460-9568.2006.05268.x