Glutamic acid

Most neurons in the brain are excited by glutamic acid. High concentrations of glutamic acid in synaptic vesicles are achieved by the vesicular glutamate transporter (VGLUT). Both ionotropic and metabotropic receptors have been characterized. Subtypes of glutamate receptors include the N-methyl-d-aspartate (NMDA) receptor, which is blocked by phencyclidine (PCP) and ketamine. NMDA receptors appear to play a role in synaptic plasticity related to learning and memory. Memantine is an NMDA antagonist introduced for treatment of Alzheimer’s dementia. Excessive activation of NMDA receptors after neuronal injury may be responsible for cell death. Glutamate metabotropic receptor activation can result in G protein-coupled activation of phospholipase C or inhibition of adenylyl cyclase.