To test if ethanol-induced GIRK2 expression could underlie the elimination of differences in neuronal properties associated with the KCNJ6 haplotype, we compared ethanol treatment with virus transduced KCNJ6 overexpression. Since ethanol has been shown to potentiate GIRK2-containing channels, we used a single treatment with 20 mM ethanol followed by fixation 24 h later. As expected, neither ethanol nor GIRK2 overexpression exhibited differences in passive neuronal properties (not shown). However, while current-induced activity increased in control cultures (p = 6.8 × 10−6, Fig. 6C), no significant difference was found in cultures exposed to 24 h ethanol (p = 0.74) and GIRK2 overexpression (p = 0.23). Similarly, while control cultures had increased ramp-induced APs (p = 5.9 × 10−4; Fig. 6A) neither GIRK overexpression (p = 0.14) or ethanol (p = 0.10) were significantly different. As a control, GIRK2 puncta count increased in a sample cell line after overexpression (line 376, p = 0.04, Fig. 6D) without an increase in circularity or solidity (not shown). These results indicate that the increased excitability in KCNJ6 minor allele haplotype cells is due to reduced
