Background and Location of Glycine
Glycine is located in the central nervous system. It is considered a “inhibitory neurotransmitter,” meaning it works to decrease a neuron's action potential (Werman et al., 1967). Glycine is most commonly
found in the spinal cord, retina, and brain stem (Werman et al., 1967). It is the simplest amino acid, its main function is to build protein molecules in
the body (Werman et al., 1967). While glycine is considered a non-essential amino
acid because it can be created from other chemicals in the body, it’s also the
second most commonly found amino acid in proteins (McIntire et al., 1997).
Primary Role and Function of Glycine
Glycine processes “motor and sensory
information that allows movement, vision, and sound” to be signaled from the
brain (Lopez-Corcuera et al., 2001). It’s mostly responsible for transmitting
chemical signals in the brain. Glycine is often co-released into the
post-synaptic terminal with GABA (gamma-amino butyric acid), which is the prime inhibitory amino acid neurotransmitter (as illustrated in the diagram below) (McIntire
et al., 1997). When glycine is released into the synapse (the space between nerve
cells), glycine binds to a receptor and makes the post-synaptic membrane (the receiving
end across the synapse) more absorbent of chlorine-ion (Lopez-Corcuera et al.,
2001). Hyperpolarization then occurs in the membrane, meaning there’s an
increase in electrical charge on both sides of the cell membrane which also
increases the membrane electric potential (Lopez-Corcuera et al., 2001). Glycine
can also sometimes be used as treatment of cognitive disorders or behavioral problems
such as schizophrenia, manic depression, alcohol addiction, and hyperactivity
(Harvey &Yee, 2013).
The video discusses the three prominent amino acids
Glutamate, GABA and Glycine. Even though the whole clip is beneficial in
understanding the amino acids and how they function in central nervous
system, the speaker specifically discusses the function of glycine starting at
4:32.
References
Harvey, R. J., & Yee, B. K. (2013). Glycine transporters as novel
therapeutic targets in
schizophrenia,alcohol dependence and
pain. Nature Reviews Drug Discovery, 12(11), 866-885.
Lopez-Corcuera, B., Geerlings, A., & Aragon, C. (2001). Glycine
neurotransmitter transporters: an
update. Molecular
membrane biology, 18(1), 13-20.
McIntire,
S. L., Reimer, R. J., Schuske, K., Edwards, R. H. and Jorgensen, E. M. (1997).
Identificationand characterization of the
vesicular GABA transporter. Nature,
389, 870-876.
Werman, R.,
Davidoff, R. A. & Aprison, M. H. (1967). Inhibition of motoneurons by
iontophoresis
of glycine. Nature, 214, 681-683.
