What are Enkephalins?

Two pentapeptides found in the brain, methionine enkephalin and leucine enkephalin. They are both morphine-like neurotransmitters in the central nervous system. They bind to cell surface receptors like opioids. Enkephalin-containing neurons are found in the brain and spinal gray matter. Its main function in the spinal cord is to regulate the feeling of pain, and its function in the brain is unknown, but it can also calm and increase the pain threshold. ^[1]

Both contain at least one amino and one

Met-enkephalin Tyr-Gly-Gly-Phe-Met

Leu-enkephalin Tyr-Gly-Gly-Phe-Leu

In the head

The role of enkephalins There is much evidence that enkephalins are neurotransmitters of special neuronal systems in the brain. This special neuron system controls the integration of sensory information belonging to pain and emotional behavior, as well as other functions. Because regional differences in enkephalin levels were found to be parallel to morphine receptors. For example, enkephalin is enriched in the part containing nerve endings, which is consistent with the prediction of a neurotransmitter, showing the immunohistochemical map of enkephalin nerve endings and axonal systems, and also supports it as a neurotransmitter effect. The existence of enkephalin-containing neuron terminals, the specific and selective effects of enkephalin and morphine on the impulsive release of cells with morphine receptors, which makes enkephalin more fully supported than most other brain transmitters .

In addition, enkephalin was also detected in the gastrointestinal tract of various animals, but was not found in any other tissues. Enkephalin is strictly restricted to the gastrointestinal tract and the brain, which is very similar to other peptides such as substance P and somatostatin. It seems that it plays a hormone-like role in the periphery and acts as a nerve in the brain. The transmitter may be the same as the enkephalin.

It is impossible for pituitary morphine-like peptides to penetrate the brain. They can regulate the pituitary functions that morphine can change. As for whether there is a relationship between morphine-like peptides such as lipotropin and enkephalin, which have longer peptide chains, from the point of view of some biologically active peptides that are fragmented by longer peptides, Lipoprotein may act as a precursor to enkephalin. For example, anorectin can be measured in the brain, while lipotropin itself is not found in the brain. It is possible that larger peptides such as anorphins are unique to the pituitary gland, while enkephalins are unique to the brain. ^[3]