The Role Of Neuropeptides In The Body

What Are Neuropeptides? by Jane Thurnell-Read

Neurotransmitters consisting of 3-40 amino acids are known as neuropeptides. They are widespread in the central nervous system and the peripheral nervous system. They have both excitatory and inhibitory actions and work in a similar way to neurotransmitters. Many neuropeptides also work as hormones in other parts of the body. There are different types of neuropeptides:

• Endorphins: discovered in 1975 by Dr John Hughes and Dr. Kosterlitz. The word is an abbreviation of endogenous morphine. Endogenous means produced naturally in the body. They are the neuropeptides in the central nervous system that act as painkillers by blocking the release of Substance P (see below); they may also have a role in memory and learning; sexual activity, and control of body temperature. They are involved in the experinece of 'runner's high'. Endorphins have a short-term effect because they are quickly broken down by endorphinases (a group of enzymes).

• Beta-endorphin is the most euphoric and is composed of 31 amino acids.

• Methionine and l eucine enkephalin: potent pain-relieving effect 200 times stronger than morphine; they work by suppressing the release of Substance P.

• Dynorphins: may be related to controlling pain and registering emotions.

• Substance P: transmits pain-related input from the peripheral nervous system to the central nervous system; may also be involved in nerve regeneration.

• Hypothalamic releasing and inhibiting hormones: regulate the release of hormones by the anterior pituitary gland, e.g. corticotropin releasing hormone.

• Angiotensin II: stimulates thirst; may regulate blood pressure in the brain; promotes release of aldosterone which increases the rate of salt and water re-absorption in the kidneys.

Some of these neuropeptides are found in Body Biochemicals 1 , 2 , 3, 4 and 5. (useful for kinesiologists and EAV practitioners.)

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