Figure 1
From: Smoking-mediated up-regulation of GAD67 expression in the human airway epithelium
Schematic illustration of GABAergic system. GABA is synthesized from glutamate by the glutamic acid decarboxylases GAD67 and GAD65. GABA is released by either a vesicle-mediated process, a vesicular neurotransmitter transporter (VGAT) or a nonvesicular process by reverse transport. GABA exerts its physiological effects through GABA-A and GABA-B receptors. The GABAergic signal is terminated by rapid uptake of GABA by specific high affinity GABA transporters (GATs). There are 4 distinct genes encoding GABA membrane transporters, GAT-1, GAT-2, GAT-3 and BGT-1. GABA is metabolized by GABA transaminase (GABA-T) and succinic semialdehyde dehydrogenase (ALDH5A1).