Final answer:
Aspartate is the amino acid neurotransmitter released at excitatory synapses, while glutamate is another excitatory amino acid neurotransmitter, and glycine and GABA are inhibitory.
Step-by-step explanation:
The neurotransmitter that is an amino acid released at excitatory synapses is aspartate. Glutamate is also a known excitatory neurotransmitter in the central nervous system (CNS), while glycine and gamma-aminobutyric acid (GABA) are usually associated with inhibitory signaling. Substances like substance P, acetylcholine, and norepinephrine have different functions and are not classified as amino acid neurotransmitters.
Glutamate is an amino acid neurotransmitter released at excitatory synapses. It is considered the main excitatory neurotransmitter in the central nervous system (CNS) and is used by around half of the neurons in the brain. Glutamate binds to specific receptors in the postsynaptic membrane to conduct excitatory transmission.