Final answer:
The body's endogenous painkillers are endorphins, which bind to opioid receptors in the brain to decrease pain and produce euphoria. The release of ß-endorphin, which can be triggered by exercise, is linked to the sensation of a runner's high and might be responsible for exercise-induced improvements in mood.
Step-by-step explanation:
The Body's Endogenous Pain Killers
The body's natural pain managing chemicals are endorphins, which are part of the body’s opioid neurotransmitter system. These peptides function as powerful endogenous painkillers in the brain and have a structure similar to that of opiates. When released, endorphins bind to opioid receptors, reducing pain and producing euphoria. Activities such as vigorous aerobic exercise can trigger the release of ß-endorphin, potentially leading to a “runner's high,” which illustrates how endorphins may positively influence anxiety and depression. However, the brain may regulate endorphin production during rest to maintain homeostasis, influencing exercise behavior and potentially leading to exercise addiction. Interestingly, some studies suggest the runner's high might instead be attributed to the release of endocannabinoids.
Endorphins are part of a family of neurotransmitters that include substance P, dopamine, serotonin, and norepinephrine. Other peptides such as vasopressin, which regulates blood pressure, and oxytocin, which induces labor and milk production, also have potent physiological functions. Notably, oxytocin was the first biologically active peptide synthesized in a lab, earning Vincent du Vigneaud a Nobel Prize in chemistry in 1955.