Endogenous opioid peptides (Endorphins)

Endorphins are endogenous opioid neuropeptides that function as neurotransmitters and hormones in the body[2][3]. The term "endorphin" is derived from "endogenous morphine," reflecting their morphine-like effects[1][2]. They are primarily produced in the pituitary gland and hypothalamus in response to pain, stress, and certain pleasurable activities[4][7]. There are more than 20 types of endorphins in the human body, with the three main classifications being alpha-endorphins, beta-endorphins, and gamma-endorphins[6]. Beta-endorphins are the most studied and potent type, playing a significant role in pain relief and feelings of euphoria[6][9]. Endorphins work by binding to opioid receptors in the brain and nervous system, similar to how morphine and other opioid drugs function[3]. In the peripheral nervous system, they inhibit pain signal transmission by blocking the release of substance P from peripheral nerves[2]. In the central nervous system, they block gamma-aminobutyric acid (GABA), which increases dopamine production and release, contributing to feelings of pleasure and reward[2][5]. The endorphin system serves multiple functions including pain relief, immune and inflammatory response regulation, stress reduction, and triggering dopamine release[5]. Endorphins are released during various activities such as exercise, laughter, sexual activity, and in response to pain or stress[7]. The "runner's high" phenomenon has been attributed to endorphin release, although some research suggests endocannabinoids may also play a significant role[2]. Biotransformation of endorphins, particularly beta-endorphin (BE 1-31), produces fragments with various pharmacological actions[9]. Understanding the endorphin system is important for developing non-addictive pain management strategies and treatments for addiction[8].

Other names

Endogenous morphineEndogenous opioidsNatural painkillersBrain's natural pain reliever

Endorphins exert their effects by binding to opioid receptors (primarily μ-receptors). In the peripheral nervous system, they inhibit pain signal transmission by blocking the release of substance P. In the central nervous system, they block GABA neurotransmitter, which in turn triggers dopamine release. They also contribute to decreasing inflammation.