dizocilpine-maleate and Liver-Cirrhosis--Alcoholic

Chronic alcohol misuse by human subjects leads to neuronal loss in regions such as the superior frontal cortex (SFC). Propensity to alcoholism is associated with several genes. gamma-Aminobutyric acid (GABA)(A) receptor expression differs between alcoholics and controls, whereas glutamate receptor differences are muted. We determined whether genotype differentiated the regional presentation of GABA(A) and glutamate-NMDA (N-methyl-d-aspartate) receptors in SFC. Autopsy tissue was obtained from alcoholics without comorbid disease, alcoholics with liver cirrhosis, and matched controls. ADH1C, DRD2B, EAAT2, and APOE genotypes modulated GABA(A)-beta subunit protein expression in SFC toward a less-effective form of the receptor. Most genotypes did not divide alcoholics and controls on glutamate-NMDA receptor pharmacology, although gender and cirrhosis did. Genotype may affect amino acid transmission locally to influence neuronal vulnerability.

Topics: Alcoholism; Brain; Case-Control Studies; Cerebral Cortex; Dizocilpine Maleate; Excitatory Amino Acid Antagonists; Gene Expression; Humans; Liver Cirrhosis, Alcoholic; Protein Isoforms; Receptors, GABA-A; Receptors, N-Methyl-D-Aspartate

Gamma-aminobutyric acidA/benzodiazepine receptor binding sites and the N-methyl-D-aspartate subclass of glutamate receptor sites were assessed in synaptic plasma membrane homogenates of cerebral cortex tissue obtained at autopsy from cirrhotic and noncirrhotic alcoholic patients and matched control subjects. The alcoholic patients consumed an average of greater than 80 g of ethanol/day, the control subjects less than 20 g/day. Postmortem delays up to approximately 100 h caused no significant loss of any of the binding sites; the patient and subject groups were closely matched for age. The affinities (KD) of the receptor sites did not differ between the patient and subject groups, nor between cortical regions. Using three different radioligands ([3H]muscimol, [3H]flunitrazepam, and [3H]diazepam), the gamma-aminobutyric acidA/benzodiazepine receptor complex was found to have greater density (Bmax) in superior frontal gyrus in alcoholic patients (which selectively shows morphological change in alcoholic patients), but was unchanged in motor cortex. Alcoholic patients with cirrhosis had much less pronounced changes. The density of the N-methyl-D-aspartate subclass of glutamate receptors, assessed with [3H]MK-801, did not vary across patient and subject groups.

Topics: Adult; Benzodiazepines; Binding Sites; Cerebral Cortex; Diazepam; Dizocilpine Maleate; Flunitrazepam; gamma-Aminobutyric Acid; Humans; Liver Cirrhosis, Alcoholic; Male; Middle Aged; Receptors, Amino Acid; Receptors, Neurotransmitter