endorfin

Endorfin, commonly spelled endorphin, refers to a group of endogenous opioid peptides produced within the central nervous system and the pituitary gland. The most studied member is beta-endorphin, a peptide derived from the proopiomelanocortin (POMC) precursor. Endorphins are part of the body's natural pain-relief system and are related to other endogenous opioid peptides such as enkephalins.

Endorphins exert their effects by binding to opioid receptors, including mu, delta, and kappa receptors, which are distributed throughout the brain and spinal cord. Through these interactions, endorphins can modulate pain signaling, influence mood, and affect reward and stress pathways. Beta-endorphin, in particular, is associated with analgesia and a sense of well-being.

Release and biological roles: Endorphins can be released in response to physical exercise, pain, emotional or physical stress, laughter, acupuncture, sexual activity, and other stimuli. Their actions can reduce pain perception, promote euphoric feelings, and influence autonomic and immune functions. They also interact with neural circuits involved in mood, motivation, and appetite.

Clinical and research notes: Endorphins are part of the broader endogenous opioid system that includes enkephalins and dynorphins. Exogenous opioids such as morphine and codeine act on the same receptors to produce analgesia and euphoria. The precise contribution of endorphins to health, pain management, and disease remains an area of ongoing scientific study.