Extracellular GABA level is decreased by genetic deletion of Best1 or MAOB but increased by overexpression of MAOB. (A) Schematic illustration for microdialysis. Extracellular GABA level is decreased by genetic deletion of Best1 or MAOB but increased by overexpression of MAOB. (A) Schematic illustration for microdialysis. ACSF, artificial cerebrospinal fluid. (B–D) Extracellular GABA (B), putrescine (C), and glutamate (D) concentration from Best1 KO, MAOB KO, and GFAP-MAOB mice (unpaired t test). Values were normalized to WT for Best1 KO and MAOB KO. Junsung Woo et al. PNAS 2018;115:19:5004-5009 ©2018 by National Academy of Sciences