Encephalins: what they are, function and types

  • Jul 26, 2021
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Encephalins: what they are, function and types

Pain is an unpleasant sensation that alerts us to possible internal abnormalities (such as inflammation of the appendix) or the dangerousness of our behaviors (as occurs when we burn ourselves). Its function is important for our own survival as we move away from external dangers and move to seek help when we assume that our body is not working properly.

Despite its important role, we are constantly trying to get rid of it. A very common method to get rid of pain is to take analgesic drugs that act on the pain sensation itself. However, did you know that our body also has analgesic substances? An example of this is endogenous opioid peptides. The endogenous opioid system is grouped into three families: endorphins, enkephalins, and dynorphins. In the following Psychology-Online article we briefly expose one of them, enkephalins: what are they, function and types.

You may also like: Endorphins: what are they, function and types

Index

  1. What are enkephalins
  2. Role of enkephalins
  3. Types of enkephalins

What are enkephalins.

Encephalins, as an endogenous opioid peptide together with endorphins and dynorphins, were discovered in 1975 by John Hughes and Hans Korsterlitz in their studies with pigs. These endogenous opioid peptides bind and interact with mu, delta, and kappa receptors.

Where are enkephalins produced? The medical dictionary of the University Clinic of Navarra[1] defines enkephalins as a opioid pentapeptide that releases the nervous system, located in both the central nervous system and the peripheral nervous system:

  • Inside of the Central Nervous System are found in the brain, specifically in the pituitary.
  • Inside of the peripheral nervous system are located in both the adrenal medulla and in the gastrointestinal tract.

A peptide is a component of proteins. These are molecules that are formed from two or more amino acids. Encephalins are pentapeptide substances, therefore they are peptides made up of five amino acids.

On the other hand, an opiate such as morphine, refers to analgesic drugs that are selectively related to opioid receptors. Analgesia is the concept used to describe the absence or reduction in pain sensation. Given the enkephalins have analgesic properties, these act on the sensation of pain.

Taking into consideration the above definitions we can conceptualize opiate peptides as those endogenous substances with opioid activity, that is, substances with opioid properties generated by itself organism.

Finally, enkephalins, like the rest of endogenous opioid peptides, are stored in neuronal vesicles. once they have been synthesized and can then be released into the intersynaptic space (or cleft synaptic). That's when act as a neurotransmitter when a nervous stimulus appears. In the following articles you will find more information about the neuronal synapse and the neurotransmitters.

Function of enkephalins.

According to the definition of the medical dictionary of the University of Navarra Clinic[1] enkephalins have a depressant function on neurons of the central nervous system. Its action affects numerous bodily processes, highlighting among all of them its effect on pain perception.

Encephalins and pain

Of all the functions of enkephalins, their role in pain has probably received the most attention. As we have advanced in the introduction, enkephalins, as endogenous opioid peptide, have an analgesic effect, namely, act on pain and they do this through modulation of nociceptinergic transmission.

The nociceptors (sensory receptors responsible for pain) begin the chain through which information is transmitted to the central nervous system. In the spinal cord, following Florentino Muñoz, E.J. (2010)[2] nociceptive fibers transmit information through the release of certain neurotransmitters such as glutamate and substance P. Thus the information is transmitted until it reaches the brain.

How then do enkephalins act on pain? Its mechanism would be precisely the modulation of the pain response through inhibition of the nociceptive signal in the spinal cord. Therefore, pain modulation is the main action of enkephalins.

Other effects of enkephalins

Although its function on pain is one of the best known and most important, we have already pointed out that enkephalins are also related to other processes. Following Florentino Muñoz, E.J. (2010)[2], enkephalins also have an effect on:

  • The control of homeostasis, that is, of the regulation that the body makes of its own processes, such as body temperature or blood sugar level.
  • The cell proliferation.
  • The cardiovascular control.
  • The stress.
  • Activities of the immune response: the immunoregulatory function of enkephalins would cause the immune system to return to its basal state after being activated.
  • The endogenous opioid system is also involved in some addictions such as addiction to nicotine, alcohol or cocaine, being necessary for these substances to exert their pleasant effects. In this article we explain the Types of additions.
  • Finally, enkephalins would also be related to activities like sex.

Types of enkephalins.

After seeing what enkephalins are like and how they act, let's see if there are different types. As we have indicated, enkephalins are made up of five amino acids. Depending on its composition They can be divided into two types that have four common amino acids and differ in one:

  • Methionine-enkephalin: it is a type of enkephalin that, in addition to the four common amino acids, contains methionine.
  • Leucine-enkephalin: Unlike the previous one, the fifth amino acid is composed of leucine instead of methionine.

If you want to know more about the difference between endorphins and enkephalins, you can consult the following article: Endorphins: what are they, function and types.

This article is merely informative, in Psychology-Online we do not have the power to make a diagnosis or recommend a treatment. We invite you to go to a psychologist to treat your particular case.

If you want to read more articles similar to Encephalins: what they are, function and types, we recommend that you enter our category of Neuropsychology.

References

  1. University of Navarra Clinic (2020). Medical dictionary. Recovered from https://www.cun.es/diccionario-medico
  2. Florentino Muñoz, E.J. (2010). Endogenous opioid peptides, pain and addiction. Synapsis, 3(1), 33-39.

Bibliography

  • American Psychiatric Association (2020). APA Dictionary of Psychology. Recovered from https://dictionary.apa.org
  • González de Rivera, J.L. (1980). Endocrine aspects of mental illness. Psyche, 4: 94-97
  • Olmeda García, M.S. (1987). Current knowledge in brain neurotransmission. Journal of the Spanish Association of Neuropsychiatry, 7 (21): 224-246
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