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.
Serotonin
The neurons of the raphe nuclei are the principal source of 5-HT release in the brain.
There are nine raphe nuclei, designated B1-B9, which contain the majority of serotonin-containing neurons (some scientists chose to group the "nuclei raphes lineares" into one nucleus), all of which are located along the midline of the brainstem, and centered on the reticular formation.
Axons from the neurons of the raphe nuclei form a neurotransmitter system reaching almost every part of the central nervous system. Axons of neurons in the lower raphe nuclei terminate in the cerebellum and spinal cord, while the axons of the higher nuclei spread out in the entire brain.