Alteration of Glutamyltranspeptidase Binding Proteins in Postmortem Brains of Heroin Addicts

Glutamyltranspeptidase binding (G) proteins play an important role in intracellular signal transduction downstream from many receptors, including opioid receptors. Moreover, it was recently reported that the β-subunits of G proteins, in addition to the α-subunits, regulate effector pathways. In this study, membrane G protein immunoreactivity was estimated by Western blotting with polyclonal antibodies (RM/1, AS/7, GC/2, QL, and SW/1) against specific G proteins (Gαs, Gαi-1,2, Gαo, Gαq, and Gβ, respectively) in postmortem temporal cortex obtained from 6 heroin addicts and 6 control subjects without a history of drug abuse. Immunoreactivities of the Gβ-subunit increased significantly ( p < 0.05) in heroin addicts, compared with controls, and that of Gαi-1,2 tended to increase in heroin addicts. Present findings suggest that the alterations in G protein-mediated signal transduction may be involved in the mechanism of opiate addiction.