Galanin-immunoreactivity in the nucleus basalis of Meynert in the rat: age-related changes and differential response to lesion-induced cholinergic cell loss.
The neuropeptide Galanin (Gal) is known to play a functional role in the basal forebrain cholinergic system. In our study, the morphology and density of the Gal-immunoreactive (Gal-IR) fiber network within the cholinergic nucleus basalis of Meynert (NBM) was investigated 1, 3 and 6 months after stereotaxic lesion with quisqualic acid in young adult (3 months old) and late middle-aged (20 months old) rats. Quantitative densitometry showed a significantly reduced Gal-IR fiber network in 20-month-old control rats. After lesion-induced cholinergic cell loss, no further changes in Gal-IR were noted in this group of aging rats during the period of investigation. In contrast, young adult animals displayed a significant increase of Gal-IR fiber density 6 months after NBM lesion. However, no hyperinnervation of individual surviving cholinergic neurons was seen. The results obtained in an animal model of cholinergic deficit support the hypothesis of age-related neuroplasticity of specific transmitter and peptide systems. Adaptive changes in Gal may play a role for the modulation of cholinergic function and could be of importance in human age-related neurodegenerative disorders, i.e. Alzheimer's disease.
Unger
J W
JW
Department of Anatomy, University of Munich, München, FRG.
Schmidt
Y
Y
D000375:Aging / Q000378:metabolism*; D000818:Animals; D002795:Choline O-Acetyltransferase / Q000276:immunology / Q000378:metabolism; D003720:Densitometry; D019004:Galanin; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology; D009479:Neuropeptides / Q000276:immunology / Q000378:metabolism*; D010275:Parasympathetic Nervous System / Q000166:cytology / Q000187:drug effects / Q000473:pathology*; D010455:Peptides / Q000276:immunology / Q000378:metabolism*; D016318:Quisqualic Acid / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D013238:Stereotaxic Techniques; D013377:Substantia Innominata / Q000276:immunology / Q000378:metabolism*
D009479:Neuropeptides; D010455:Peptides; D019004:Galanin; D016318:Quisqualic Acid; D002795:Choline O-Acetyltransferase