A class of drugs called opioids is frequently prescribed to treat pain. They interact with particular receptors in the peripheral tissues and central nervous system to provide their analgesic (pain-relieving) actions. Modulation of pain perception and transmission is the main way that opioids work. This is how opioids function to reduce pain:

Opioid receptor activation: Opioids bind to and activate G protein-coupled opioid receptors, which are distributed throughout the central and peripheral nervous systems (CNS and SNS). Opioid receptors come in three primary varieties: mu (μ), delta (δ), and kappa (κ). Of them, mu receptors are principally in charge of mediating the opioids’ analgesic effects.

• One important neurotransmitter that helps the central nervous system receive pain signals from the peripheral is substance P. Opioids lessen the transmission of pain signals from the site of injury or inflammation to the brain, which lowers the sense of pain by lowering the release of substance P.

  Modulation of Descending Pain Pathways: Another method that opioids relieve pain is by influencing the central nervous system’s descending pain pathways. These routes entail the release of endogenous opioid peptides from neurons in the brainstem and other areas of the brain, including enkephalins and endorphins. Endogenous opioids reduce pain perception by blocking the transmission of pain signals and binding to opioid receptors in the brain and spinal cord.

  Changes in the Brain’s Processing of Pain