Glutamate (neurotransmitter)
In neuroscience, glutamate 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 excitatory neurotransmitter in the vertebrate nervous system. It is used by every major excitatory function in the vertebrate brain, accounting in total for well over 90% of the synaptic connections in the human brain. It also serves as the primary neurotransmitter for some localized brain regions, such as cerebellum granule cells.
Neurokinin A
Neurokinin A (formally known as substance K) is a member of the tachykinin family of neuropeptide neurotransmitters. Tachykinins are important contributors to nociceptive processing, satiety, and smooth muscle contraction. Tachykinins are known to be highly excitatory neurotransmitters in major central neural systems. Neurokinin A is ubiquitous in both the central and peripheral mammalian nervous systems, and seems to be involved in reactions to pain and the inflammatory responses. It is produced from the same preprotachykinin A gene as the neuropeptide substance P. Both substance P and neurokinin A are encoded by the same mRNA, which when alternatively spliced can be translated into either compound. It has various roles in the body of humans and other animals, specifically stimulation of extravascular smooth muscle, vasodilation, hypertensive action, immune system activation, and pain management. The deduced amino acid sequence of neurokinin A is as follows: 
with amidation at the C-terminus.