Role of acetyl-L-carnitine in the brain: revealed by Bioradiography.
To elucidate the role of acetyl-L-carnitine in the brain, we used a novel method, 'Bioradiography,' in which the dynamic process could be followed in living slices by use of positron-emitter labeled compounds and imaging plates. We studied the incorporation of 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) into rat brain slices incubated in oxygenated Krebs-Ringer solution. Under the glucose-free condition, [18F]FDG uptake rate decreased with time and plateaued within 350 min in the cerebral cortex and cerebellum, and the addition of 1 or 5mM acetyl-L-carnitine did not alter the [18F]FDG uptake rate. When a glutaminase inhibitor, 0.5mM 6-diazo-5-oxo-L-norleucine (DON), was added under the normal glucose condition, [18F]FDG uptake rate decreased. Acetyl-L-carnitine (1mM), which decreased [18F]FDG uptake rate, reversed this DON-induced decrease in [18F]FDG uptake rate in the cerebral cortex. These results suggest that acetyl-L-carnitine can be used for the production of releasable glutamate rather than as an energy source in the brain.
Tanaka
Masaaki
M
Department of Physiology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka 545-8585, Japan.
Nakamura
Fusao
F
Mizokawa
Shigekazu
S
Matsumura
Akira
A
Matsumura
Kiyoshi
K
Watanabe
Yasuyoshi
Y
D000108:Acetylcarnitine / Q000502:physiology*; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D002540:Cerebral Cortex / Q000378:metabolism; D003980:Diazooxonorleucine / Q000494:pharmacology; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005947:Glucose / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D008954:Models, Biological; D011859:Radiography / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014055:Tomography, Emission-Computed
D000964:Antimetabolites, Antineoplastic; D003980:Diazooxonorleucine; D019788:Fluorodeoxyglucose F18; D018698:Glutamic Acid; D000108:Acetylcarnitine; D005947:Glucose