Effects of Aging and Nerve Growth Factor on Neuropeptide Expression and Cholinergic Innervation of the Rat Basolateral Amygdala

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Pereira, PA (Author) FMUP; Tavares, M (Author) Other; Laires, M (Author) Other; Mota, B (Author) Other; Madeira, MD (Author) Other; Paula-Barbosa, MM (Author) Other; Cardoso, A (Author) Other

Journal

Title: BIOLOGY-BASEL

Vol. 13

Final page: 155

Publisher: MDPI

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 0 Citations

Other information

Authenticus ID: P-010-1S3

DOI: 10.3390/biology13030155

Abstract (EN): Simple Summary The basolateral amygdala (BLA) contains neurons that produce neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP). These neuropeptides are involved in the regulation of several brain functions and behaviors, and there is evidence that, in some brain regions, the acetylcholine might modulate its expression. Thus, we study if aging alters the BLA densities of NPY- and VIP-positive neurons and cholinergic varicosities. We also investigate if any potential change in these parameters might be related to insufficient trophic support provided by the neurotrophin nerve growth factor (NGF). We found that the density of NPY-positive neurons was reduced in aged rats, whereas the density of VIP-immunoreactive neurons was unchanged. The decreased expression of NPY was fully reversed by intracerebroventricular administration of NGF. The density of cholinergic varicosities was similar in adult and old rats, and the infusion of NGF to aged rats increased their density to greater than the values of adult and old rats. These results indicate that the NPY expression in the BLA is affected by aging, and also show that this age-related change can be associated with alterations in the NGF trophic support. Furthermore, the results also show that the BLA cholinergic innervation is particularly resistant to age effects.Abstract The basolateral amygdala (BLA) contains interneurons that express neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), both of which are involved in the regulation of functions and behaviors that undergo deterioration with aging. There is considerable evidence that, in some brain areas, the expression of NPY and VIP might be modulated by acetylcholine. Importantly, the BLA is one of the brain regions that has one of the densest cholinergic innervations, which arise mainly from the basal forebrain cholinergic neurons. These cholinergic neurons depend on nerve growth factor (NGF) for their survival, connectivity, and function. Thus, in this study, we sought to determine if aging alters the densities of NPY- and VIP-positive neurons and cholinergic varicosities in the BLA and, in the affirmative, if those changes might rely on insufficient trophic support provided by NGF. The number of NPY-positive neurons was significantly reduced in aged rats, whereas the number of VIP-immunoreactive neurons was unaltered. The decreased NPY expression was fully reversed by the infusion of NGF in the lateral ventricle. The density of cholinergic varicosities was similar in adult and old rats. On the other hand, the density of cholinergic varicosities is significantly higher in old rats treated with NGF than in adult and old rats. Our results indicate a dissimilar resistance of different populations of BLA interneurons to aging. Furthermore, the present data also show that the BLA cholinergic innervation is particularly resistant to aging effects. Finally, our results also show that the reduced NPY expression in the BLA of aged rats can be related to changes in the NGF neurotrophic support.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13