Fig. 1. Interrelationships of GABA metabolism.
Arrows (downward/upward) indicate the direction of metabolite disruption in aldh5a1−/− mice. Abbreviations: Gln, glutamine; Glu, glutamate; GABA, 4-aminobutyrate; SSA, succinic semialdehyde; GHB, gamma-hydroxybutyrate; mTOR, mechanistic target of rapamycin; GAD, glutamic acid decarboxylase; GABA-T, GABA-transaminase; SSR, succinic semialdehyde reductase; GHBDH, gamma-hydroxybutyrate dehydrogenase; SSADH, succinic semialdehyde dehydrogenase (site of the defect in patients with SSADHD); GLS, glutamate synthetase; GLNASE, glutaminase. Vigabatrin (VGB), an antiepileptic and irreversible inhibitor of GABA-T, is a frequently employed therapeutic agent for SSADHD.