γ-Aminobutyric acid (GABA) is an inhibitory neurotransmitter that acts through heteromeric ligand-gated ion channels, GABAA and GABAC, and a G protein-coupled receptor, GABAB. (±)-Baclofen is a selective agonist of GABAB (IC50 = 200 nM). By activating GABAB, (±)-baclofen causes skeletal muscle relaxation and blocks spasticity. It also modifies animal responses to alcohol and cocaine.
