ABCC9 and multiple system atrophy: The expression of the GABAB receptor subunit 2 was found to be significantly (p < 0.05) reduced in the MSA-P MSNs at day 70 ± 3 days, compared with the control MSNs, whereas the expression of the GABAB receptor subunit 1, as well as SUR1 and SUR2, did not differ between the groups (Figure 6B).