EFFECTS OF BRAIN MEMBRANES ON H-1 NUCLEAR-MAGNETIC-RESONANCE SIGNAL INTENSITY OF ETHANOL IN-VITRO

Citation
V. Govindaraju et al., EFFECTS OF BRAIN MEMBRANES ON H-1 NUCLEAR-MAGNETIC-RESONANCE SIGNAL INTENSITY OF ETHANOL IN-VITRO, Alcohol and alcoholism, 32(6), 1997, pp. 671-681
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Substance Abuse
Journal title
ISSN journal
0735-0414
Volume
32
Issue
6
Year of publication
1997
Pages
671 - 681
Database
ISI
SICI code
0735-0414(1997)32:6<671:EOBMOH>2.0.ZU;2-7
Abstract
In vivo proton nuclear magnetic resonance (H-1 NMR) studies of ethanol in animal and human brains have shown that only a fraction of ethanol in brain is visible by NMR. The goals of these in vitro H-1 NMR exper iments were to determine: (1) whether the interaction of ethanol with brain membranes in vitro diminishes ethanol visibility; and (2) if a m agnetization transfer (MT) effect can be observed for the interaction of ethanol with brain membranes in vitro. Furthermore, pilot studies w ere performed to determine if the brain membranes from rats chronicall y exposed to ethanol had a different effect on ethanol NMR visibility and spin-spin relaxation time (T2) than brain membranes obtained from control rats. Results show that the NMR visibility of ethanol is lower in rat brain membrane suspensions in vitro as compared to ethanol in saline solutions. The factors decreasing ethanol NMR visibility are T2 relaxation, water presaturation time, and off-resonance saturation by a frequency-dependent MT pulse. One-pulse NMR measurements without wa ter presaturation showed that ethanol visibility was significantly inc reased by 15% in brain membrane suspensions of ethanol-fed rats, sugge stive of decreased ethanol partitioning compared to controls. Furtherm ore ethanol in brain membrane suspensions from ethanol-fed rats showed smaller MT effects than from control rats. These results provide a me chanism for decreased NMR visibility of ethanol in brain, and suggest that chronic exposure to ethanol produces membrane changes which resul t in increased NMR visibility.