title: Aging causes partial loss of basal forebrain but no loss of pontine reticular cholinergic neurons.
abstract: Cholinergic degeneration occurs in several neurodegenerative diseases. To investigate whether normal aging causes selective neurodegeneration, we compared counts of cholinergic neurons in the medial septum/vertical limb of the diagonal band and pedunculopontine and laterodorsal tegmental nuclei of the brainstem in young and aged Long-Evans rats characterized for their spatial learning ability in the Morris water maze. A subset of aged rats (aged-unimpaired) learned the spatial learning task as young rats, whereas another group (age-impaired) showed poorer learning than young animals. In the medial septum/diagonal band, there was a significant loss (-23%, P < 0.02) of cholinergic neurons in aged-impaired animals compared with young subjects. In the brainstem, there were no significant differences in cholinergic cell number in any group. This selective loss of cholinergic neurons may, in part, account for the cognitive deficits observed in aging and, considering previous findings in this model, may be related to oxidative stress.
authors.affiliation: Department of Neuroscience, Mayo Clinic, Jacksonville, Florida 32224, USA. Baskerville.Karen@mayo.edu
authors.forename: Karen A
authors.initials: KA
authors.lastname: Baskerville
authors.forename: Caroline
authors.initials: C
authors.lastname: Kent
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Nicolle
authors.forename: Michela
authors.initials: M
authors.lastname: Gallagher
authors.forename: Michael
authors.initials: M
authors.lastname: McKinney
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000375:Aging / Q000473:pathology* / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000502:physiology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D007150:Immunohistochemistry; D007859:Learning Disabilities / Q000473:pathology / Q000503:physiopathology; D008297:Male; D018782:Maze Learning / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D016548:Prosencephalon / Q000166:cytology*; D051381:Rats; D020318:Rats, Long-Evans; D012154:Reticular Formation / Q000166:cytology*; D013028:Space Perception / Q000502:physiology
chemical_list: D002795:Choline O-Acetyltransferase; D000109:Acetylcholine