Answer: TFB-TBOA is a chemical that inhibits the action of the excitatory amino acid transporter protein.
When the excitatory neurotransmitter glutamate is released into the synapse, it activates postsynaptic glutamate receptors until the neurotransmitter is cleared from the space. The purpose of the excitatory amino acid transporter, or EAAT, is to take up molecules of glutamate back into the presynaptic cell for repackaging into vesicles and further release. TFB-TBOA is a molecule that acts to inhibit these transporters. As a result, TFB-TBOA can increase the amount of glutamatergic signaling that is occuring.
When given in vivo, TFB-TBOA may cause seizures. The continuous action of glutamate at the postsynaptic glutamate receptors may cause the excitatory synapses to fire excessively, resulting in epileptic activity.
In a slice preparation during electrophysiological recordings, TFB-TBOA main effect would be to possible change the kinetics of a glutamate release. An excitatory post synaptic potential or current (ePSP or ePSC) may have a longer “tail” of decay during stimulation of glutamatergic synapses. Because the glutamate is not cleared from the synapse as quickly, it will continue to activate receptors postsynaptically for a longer duration than normal.
TFB-TBOA has an IC50 of around 20 nM for EAAT1 and EAAT2, and 300 nM for EAAT3. It has no action at the EAAT4 or EAAT5.