glutamate

Chemically, glutamate is the conjugate base of glutamic acid (an amino acid). It is an anion; its sodium salt is monosodium glutamate (MSG), which has an umami flavor.

Glutamate is an excitatory neurotransmitter. Brief, excitatory pulses of glutamate are a major way in which neurons communicate; it occurs in something like 80% of all synapses.

Sources:

• 4.1 Glutamate receptors - YouTube