ALTERATIONS OF GUANINE-NUCLEOTIDE-BINDING PROTEINS IN POSTMORTEM HUMAN BRAIN IN ALCOHOLICS

Qualitative and quantitative alterations of G proteins in membrane pre parations from parietal and temporal cortex regions in post-mortem bra ins obtained from alcoholics and controls matched with respect to age and post-mortem delay were investigated by Western-blotting with polyc lonal antibodies against specific G protein subunits and functional ph otoaffinity GTP binding. Quantitative immunoblotting showed that only Gsalpha (52 kDa species) in temporal cortex was significantly decrease d (30%, P < 0.05) in alcoholics compared with controls. Moreover, etha nol-stimulated photoaffinity GTP labeling of Gsalpha and Gi/oalpha was decreased in alcoholics in both cortex regions. These results suggest that disturbances of G protein-mediated signal transduction may be in volved in the pathophysiology of alcoholics.