Proton MRS of oral creatine supplementation in rats. Cerebral metabolite concentrations and ischemic challenge.
Proton magnetic resonance spectroscopy (MRS) was employed to determine the concentrations of N-acetylaspartate (NAA), total creatine (tCr), choline-containing compounds (Cho), myo-inositol (Ins), glucose (Glc), and lactate (Lac) in rat brain before and after 10 days of oral supplementation of 2.6 g Cr-monohydrate per kg body weight per day. Measurements were performed both in vitro (n = 16) and in vivo (n = 6). The neuroprotective potential of oral Cr was assessed by dynamically monitoring brain Glc and Lac in response to transient global ischemia (12 min). In comparison to controls the in vitro concentrations of Cr (13.1 +/- 9.3%) and Ins (12.7 +/- 14. 0%) were significantly increased in Cr-fed rats. Under in vivo conditions, the data revealed trends for elevated tCr (4.7%) and Ins (10.6%) which were enhanced in the concentration ratios of tCr:Cho (10.2%) and Ins:Cho (17.8%). Together with an increased Glc level (27.3%), the observation of a statistically significant decrease of brain Lac (-38.5 +/- 19.3%) in Cr-fed rats may reflect a shift of the energy metabolism from non-oxidative toward oxidative glycolysis. One hour after global ischemia most of the metabolic differences between Cr-fed rats and controls were retained. The increased Glc level (44.4 +/- 33.3%) reached statistical significance, but the accumulation of Lac and its time course during ischemia and early reperfusion showed no differences between Cr-fed rats and controls.
Michaelis
T
T
Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, D-37070 Göttingen, Germany. tmichae@gwdg.de
Wick
M
M
Fujimori
H
H
Matsumura
A
A
Frahm
J
J
D000284:Administration, Oral; D000693:Anaerobiosis; D000818:Animals; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D003401:Creatine / Q000493:pharmacokinetics / Q000494:pharmacology*; D019587:Dietary Supplements; D004195:Disease Models, Animal; D006019:Glycolysis / Q000187:drug effects; D002546:Ischemic Attack, Transient / Q000178:diet therapy* / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology*; D011522:Protons; D051381:Rats; D017208:Rats, Wistar
D018696:Neuroprotective Agents; D011522:Protons; D003401:Creatine