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.
Neuromedin U
Neuromedin U is a highly conserved neuropeptide present in many species, existing as multiple isoforms. For example, in humans it is a 25 amino acid peptide (U-25) in rats it is 23-aas long (U-23) and it has been found to be as low as 8-aas long in some mammals. NMU-8 is identical to the C terminus of NMU-25, thus is the most highly conserved region of the entire peptide. The relative contribution of the different isoforms to the biological function of neuromedin U is generally not well understood. Neuromedin U, like many neuroactive peptides, is amidated at the C-terminus, and all isoforms have identical C-terminal heptapeptides.