A [11C]Ro15 4513 PET study suggests that alcohol dependence in man is associated with reduced α5 benzodiazepine receptors in limbic regions.
Preclinical evidence suggests the α5 subtype of the GABA-benzodiazepine receptor is involved in some of the actions of alcohol and in memory. The positron emission tomography (PET) tracer, [(11)C]Ro15 4513 shows relative selectivity in labelling the α5 subtype over the other GABA-benzodiazepine receptor subtypes in limbic regions of the brain. We used this tracer to investigate the distribution of α5 subtype availability in human alcohol dependence and its relationship to clinical variables. Abstinent (>6 weeks) alcohol-dependent men and healthy male controls underwent an [(11)C]Ro15 4513 PET scan. We report [(11)C]Ro15 4513 brain uptake for 8 alcohol-dependent men and 11 healthy controls. We found a significant reduction in [(11)C]Ro15 4513 binding in the nucleus accumbens, parahippocampal gyri, right hippocampus and amygdala in the alcohol-dependent compared with the healthy control group. Levels of [(11)C]Ro15 4513 binding in both hippocampi were significantly and positively associated with performance on a delayed verbal memory task in the alcohol-dependent but not the control group. We speculate that the reduced limbic [(11)C]Ro15 4513 binding seen here results from the effects of alcohol, though we cannot currently distinguish whether they are compensatory in nature or evidence of brain toxicity.
Lingford-Hughes
Anne
A
Psychopharmacology Unit, Dorothy Hodgkin Building, University of Bristol, Bristol, UK. anne.lingford-hughes@ic.ac.uk
Reid
Alastair G
AG
Myers
James
J
Feeney
Adrian
A
Hammers
Alexander
A
Taylor
Lindsay G
LG
Rosso
Lula
L
Turkheimer
Federico
F
Brooks
David J
DJ
Grasby
Paul
P
Nutt
David J
DJ
D000328:Adult; D000437:Alcoholism / Q000000981:diagnostic imaging / Q000378:metabolism*; D001386:Azides / Q000493:pharmacokinetics; D001569:Benzodiazepines / Q000493:pharmacokinetics; D002250:Carbon Radioisotopes; D016022:Case-Control Studies; D000431:Ethanol / Q000378:metabolism / Q000506:poisoning*; D006801:Humans; D008032:Limbic System / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008568:Memory / Q000187:drug effects; D009714:Nucleus Accumbens / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D049268:Positron-Emission Tomography / Q000379:methods; D011963:Receptors, GABA-A / Q000378:metabolism*
D001386:Azides; D002250:Carbon Radioisotopes; D011963:Receptors, GABA-A; D001569:Benzodiazepines; D000431:Ethanol; C042957:Ro 15-4513