PTPA and major depressive disorder: Apart from cerebral ischemia, which is an extreme pathological situation, interfering with the GABAB receptor/PP2A interaction might also be effective for the treatment of less severe neurological diseases associated with downregulation of GABAB receptors and a disturbed excitation/inhibition balance such as addiction, anxiety, and depression (Maeda et al., 2006; Padgett et al., 2012; Hearing et al., 2013; Lecca et al., 2016).