Glutamate is also a
neurotransmitter with an
excitatory (rather than
inhibitory) effect on the
Central Nervous System. This, rather than the
placebo effect as some claim, is probably what accounts for
Chinese Restaurant Syndrome after consuming high levels of
Monosodium Glutamate. (Incidentally, high levels of the neurotransmitter
dopamine are known to cause
psychosis and symptoms of
schizophrenia).
Glutamate is the neurotransmitter released by the hair cells of the inner ear responsible for detection of sound. Caffeine acts as a stimulant by suppressing levels of adenosine in the brain, which in turn increases the levels of glutamate.