Enhancement of learning capacity and cholinergic synaptic function by carnitine in aging rats.
The effects of a carnitine derivative, acetyl-L-carnitine (ALCAR), on the cognitive and cholinergic activities of aging rats were examined. Rats were given ALCAR (100 mg/kg) per os for 3 months and were subjected to the Hebb-Williams tasks and a new maze task, AKON-1, to assess their learning capacity. The learning capacity of the ALCAR-treated group was superior to that of the control. Cholinergic activities were determined with synaptosomes isolated from the cortices. The high-affinity choline uptake by synaptosomes, acetylcholine synthesis in synaptosomes, and acetylcholine release from synaptosomes on membrane depolarization were all enhanced in the ALCAR group. This study indicates that chronic administration of ALCAR increases cholinergic synaptic transmission and consequently enhances learning capacity as a cognitive function in aging rats.
Ando
S
S
Department of Membrane Biochemistry, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan. andos@tmig.or.jp
Tadenuma
T
T
Tanaka
Y
Y
Fukui
F
F
Kobayashi
S
S
Ohashi
Y
Y
Kawabata
T
T
D000108:Acetylcarnitine / Q000494:pharmacology*; D000109:Acetylcholine / Q000096:biosynthesis / Q000378:metabolism; D000200:Action Potentials / Q000187:drug effects; D000375:Aging / Q000523:psychology*; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology; D002799:Cholinergic Fibers / Q000187:drug effects*; D003071:Cognition / Q000187:drug effects; D004038:Diet, Reducing; D004353:Drug Evaluation, Preclinical; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects; D008959:Models, Neurological; D051381:Rats; D011916:Rats, Inbred F344; D009435:Synaptic Transmission / Q000187:drug effects*; D013574:Synaptosomes / Q000378:metabolism; D015431:Weight Loss
D000108:Acetylcarnitine; D000109:Acetylcholine