Basal forebrain cholinergic neurons in aged rat brain are more susceptible to ibotenate-induced degeneration than neurons in young adult brain.
Choline acetyltransferase (ChAT) activity, acetylcholinesterase (AChE) activity, and [3H]nicotine binding site density were measured in neocortex from unoperated (control) and nucleus basalis (NB)-lesioned young (2-3 months old) and aged (23-24 months old) rats. In control animals, neither enzyme activities nor the density of nicotine binding sites were altered as a function of age. However, age-related differences were apparent 2 weeks following unilateral infusions of ibotenic acid into the right NB. NB lesion-induced decreases in enzyme activities were significantly greater in ipsilateral neocortices from aged rats; ChAT and AChE activities in young animals decreased by 59 and 53%, respectively, while both enzyme activities in aged rats decreased by 72%. NB lesions decreased significantly the density of nicotine binding sites in ipsilateral neocortices from both young and aged rats; binding decreased by 23-26% in young rats and by 31-34% in aged animals. Results indicate that the basal forebrain cholinergic system in the aged rat is more susceptible to ibotenate-induced degeneration than neurons in young animals.
Zawia
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Department of Pharmacology and Therapeutics, College of Medicine, University of South Florida, Tampa 33612-4799.
Arendash
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GW
Wecker
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D000110:Acetylcholinesterase / Q000378:metabolism; D000375:Aging / Q000502:physiology*; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology / Q000201:enzymology; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D007051:Ibotenic Acid / Q000633:toxicity*; D008297:Male; D009410:Nerve Degeneration / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects*; D010275:Parasympathetic Nervous System / Q000166:cytology*; D016548:Prosencephalon / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000187:drug effects
D011978:Receptors, Nicotinic; D007051:Ibotenic Acid; D002795:Choline O-Acetyltransferase; D000110:Acetylcholinesterase