The effects of nerve growth factor upon the neuropeptide content of the suprachiasmatic nucleus of rats withdrawn from ethanol are mediated by the nucleus basalis magnocellularis

• Type: Article in International Scientific Journal
• Date: 2004

Authors

Paula Barbosa, MM (Author) Other; Pereira, PA (Author) FMUP; Cardoso, A (Author) Other; Madeira, MD (Author) FMUP; Cadete Leite, A (Author) Other

Journal

Title: Journal of Neurocytology

Vol. 33

Pages: 453-463

ISSN: 0300-4864

Publisher: Kluwer Academic Publishers

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 7 Citations

Scientific classification

FOS: Medical and Health sciences > Basic medicine

Other information

Authenticus ID: P-000-9S4

DOI: 10.1023/b:neur.0000046575.32270.e6

Abstract (EN): It has been previously shown that withdrawal from alcohol decreases the synthesis and expression of vasopressin (VP) and vasoactive intestinal polypeptide (VIP) in the suprachiasmatic nucleus (SCN), and that the infusion of NGF over 1 month completely restores these changes. Because SCN neurons do not express TrkA, NGF might have exerted its effects either through direct signalling of the neurons via p75(NTR) or by enhancing the activity of the cholinergic afferents to the SCN, which arise from the nucleus basalis magnocellularis (NBM). The observation that the infusion of NT-3 to withdrawn rats does not elicit any change in neuropeptide expression in the SCN suggests that ACh might be implicated in this process, a hypothesis that we have attempted to clarify in this study. For this purpose we destroyed, with quinolinic acid, the NBM of rats withdrawn from ethanol and later infused them with NGF over a period of 13 days. The total number and the somatic volume of SCN neurons immunoreactive for VP and VIP were stereologically estimated. No differences were found in the total number of neurons between quinolinic-injected NGF-treated withdrawn animals and intact withdrawn rats. However, the somatic volume of SCN neurons from quinolinic-injected animals was significantly reduced relative to control and withdrawn rats. The present results unequivocally demonstrate that the trophic effects exerted by NGF upon SCN neurons do not depend on direct neuronal signalling. Instead, they are indirect and, according to our results, NBM neurons, whose axons give rise to a cholinergic projection to the SCN, seem to be essential for eliciting those effects.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11