The influence of alcoholism and cirrhosis on benzodiazepine receptor function

Abstract

In a previous study we reported that the affinity of the platelet benzodiazepine receptor was greater in alcoholic cirrhotic patients compared with normal controls and that there were detectable ligands for the neuronal benzodiazepine receptor in plasma from both alcoholic and nonalcoholic cirrhotic patients. The aim of the present study was to assess the separate contributions of alcoholism and cirrhosis to the presence of ligands in plasma for the neuronal and peripheral benzodiazepine receptors and to changes in peripheral benzodiazepine receptor binding in platelets. These parameters were measured in 10 alcoholic cirrhotics, 9 nonalcoholic cirrhotics, 7 alcoholics with a normal liver function, and 15 nonalcoholic subjects and normal liver function. Both groups of alcoholics had been abstinent for several months and the nonalcoholic groups had abstained for 24 h before the study. The concentration of ligands for the peripheral benzodiazepine receptor were significantly higher in both cirrhotic groups compared with the other two groups, suggesting that cirrhosis was responsible for this accumulation. Furthermore, the cirrhotic patients with detectable concentrations of these ligands had significantly poorer episodic memory than those without ligands. However, the presence of ligands for the peripheral benzodiazepine receptor did not correlate with the change in receptor affinity, which was increased in the alcoholic cirrhotic group compared with all other groups. Neither cirrhosis nor alcoholism altered the peripheral benzodiazepine receptor number. The cirrhotic patients with detectable ligands for the neuronal benzodiazepine receptor showed psychomotor slowing and executive dysfunction. The results suggest that the ligands for the peripheral benzodiazepine receptor may contribute to some of the cognitive deficits seen in hepatic encephalopathy, but are not responsible for the receptor affinity change seen in the alcoholic cirrhotics. This affinity change is not solely due to the effects of alcohol and could possibly serve as a marker for those at risk for developing alcoholic cirrhosis.