DL-TBOA is an inhibitor of excitatory amino acid transporters (EAATs), with IC50 values of 67 and 5.5 μM for glutamate uptake in COS-1 cells expressing human EAAT1 and EAAT2, respectively. It inhibits inward currents induced by L-aspartate in EAAT4-expressing Xenopus oocytes (Ki = 4.4 μM) and by L-glutamate in EAAT5-expressing oocytes (Ki = 3.2 μM) voltage-clamped at -60 mV. In vivo, DL-TBOA (500 μM, intrahippocampal perfusion) increases extracellular aspartate, glutamate, and alanine levels in rat hippocampus. Intrahippocampal injection of DL-TBOA increases lesion volume in the rat CA1 region in a dose-dependent manner and induces hyperexcitability, wet-dog shakes, salivation, forelimb myoclonus, limbic seizures, and epileptic EEG discharges at a dose of 25 nmol. DL-TBOA (5 and 10 μg, intrathecal) induces antinociception in the second phase of the formalin test in rats when administered 10 minutes prior to formalin.
