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.
Choline transporter
Choline is a necessary reagent for the synthesis of acetylcholine in the central nervous system. Neurons get their choline by specific protein transporters known as choline transporters. In the human brain microvascular endothelial cells, two systems initiate the choline absorption. The first system is known as the Choline transporter-like protein 1, or CTL1. The second system is the Choline transporter-like protein 2, or CTL2. Those two systems are found on the plasma membrane of the brain microvascular endothelial cells. They are also found on the mitochondrial membrane. CTL2 was found to be highly expressed on the mitochondria. Meanwhile, CTL1 was mostly found on the plasma membrane of those microvascular cells.