Roles of β-Endorphin in Stress, Behavior, Neuroinflammation, and Brain Energy Metabolism

Abstract

β-Endorphins are peptides that exert a wide variety of effects throughout the body. Produced through the cleavage pro-opiomelanocortin (POMC), β-endorphins are the primarily agonist of mu opioid receptors, which can be found throughout the body, brain, and cells of the immune system that regulate a diverse set of systems. As an agonist of the body's opioid receptors, β-endorphins are most noted for their potent analgesic effects, but they also have their involvement in reward-centric and homeostasis-restoring behaviors, among other effects. These effects have implicated the peptide in psychiatric and neurodegenerative disorders, making it a research target of interest. This review briefly summarizes the basics of endorphin function, goes over the behaviors and regulatory pathways it governs, and examines the variability of β-endorphin levels observed between normal and disease/disorder affected individuals.

Keywords: behavior; brain energy metabolism; neurodegeneration; neuroinflammation; psychiatric disorders; stress; β-endorphins.

Figure 1

The interrelation between the hypothalamic–pituitary–adrenal (HPA), stress, and β-endorphins. β-Endorphins both attenuate the stress response and act to reduce levels of inflammatory cytokines, while increasing levels of anti-inflammatory cytokines, primarily through interaction with the mu-opioid receptor.

Figure 2

β-Endorphins exert a variety of effects on the brain that may impact brain health and neurodegenerative disorder.