Amino acids are the most abundant neurotransmitters in the brain. Neurotransmitters are synthesized and stored in presynaptic terminals, released from terminals upon stimulation with specific receptors on the postsynaptic cells. Chemical and electrical synapses are specialized biological structures found in the nervous system; they connect neurons together and transmit signals across the neurons. The process of synaptic transmission generates or inhibits electrical impulses in a network of neurons for the processing of information. Glutamate is the primary excitatory neurotransmitter in the brain, while GABA is the principal inhibitory neurotransmitter. The balance of glutamatergic and GABAergic tone is crucial to normal neurologic function. Through synaptic transmission, this information is communicated from the presynaptic cell to the postsynaptic cell. Amino acid neurotransmitters primarily glutamic acid, GABA, aspartic acid, and glycine are single amino acid residues released from presynaptic nerve terminals in response to an action potential and cross the synaptic cleft to bind with specific receptor on the postsynaptic membrane. The integral role of amino acid neurotransmitters is important on the normal functioning of the brain. The presynaptic and postsynaptic events in chemical synapses are subject to use dependent and highly regulated as per the changes in synaptic neurotransmitter release and function.
Part of the book: Neurochemical Basis of Brain Function and Dysfunction