These changes in GABAA receptor function are accompanied by changes in receptor plasticity. Several studies reported changes in GABAA receptor subunit expression in post-mortem brains from human alcoholics, although results are often controversial. Lewohl et al. (1997) showed that GABAA receptor α1 subunit mRNA expression was elevated in human alcoholic superior frontal cortex, compared with non-alcoholic subjects, while α2 and α3 mRNA did not change. Further, α1 protein expression was greater in the superior frontal compared to the motor cortex of cirrhotic alcoholics, but no such difference was observed in controls or uncomplicated alcoholics. In contrast, α3 peptide expression was lower in superior frontal than in motor cortex of uncomplicated alcoholics (Lewohl et al. 2001). However, Mitsuyama et al. (1998) found no difference in α1 and α4 subunits mRNA expression in frontal cortex between controls and alcoholics, but β3 mRNA expression was elevated in non-cirrhotic alcoholics. These changes were not accompanied by changes in α1, α4, or β2/3 protein expression between alcoholics and controls. Others have reported no differences in mRNA expression for any β subunit between alcoholics and controls (Buckley and Dodd 2004).
