Glutamate is an excitatory neurotransmitter capable of causing a metabolic injury to neurons. In the hippocampus, GABAergic neurons have been found vulnerable to excitotoxic action of glutamate at the kainate receptor. These receptors are most dense in sectors CA3 and CA2 of the hippocampus, where nanomolar (nM) concentrations of kainic acid have been associated with pronounced and persistent depolarization of CA3 pyramidal neurons. This involving the conduction of excitatory activity along the mossy fiber projections from the area dentate granule cells to the CA3 neurons. Stimulation of this receptor type has been associated with paroxysmal spikes similar to seizures.