Neurotransmitters play a key role in the function of the central nervous system and can either prompt or suppress the further signaling of nearby neurons. Endorphins are produced as a response to certain stimuli, especially stress, fear or pain.
GABA, or gamma-aminobutyric acid, is the most abundant inhibitory neurotransmitter in the brain. While GABA is an amino acid, it is classified as a neurotransmitter and helps induce relaxation and sleep. It balances the brain by inhibiting over-excitation.
Glutamate (neurotransmitter) In neuroscience, glutamate generally refers to the anion of glutamic acid in its role as a neurotransmitter: a chemical that nerve cells use to send signals to other cells. It is by a wide margin the most abundant neurotransmitter in the vertebrate nervous system.