About morphinemu-opioid agonist,natural opium alkaloid, a highly potent narcotic analgesic.mechanism of action of morphinethis opioid analgesic act on the cns. its analgesic action is due to the action on opioid receptors. there are different types of opioid receptors in the body- they are mu receptors, delta receptors, and kappa receptors etc. its analgesia, euphoria and dependence are due to its action on mu-1 receptors. it reduces the pain threshold, there by reducing the perception of pain. this action is assisted by the feeling of well being. respiratory depression and inhibition of intestinal movements is due to its action on mu-2 receptors. its action on kappa receptors cause spinal analgesia.it directly acts on the cough centre and suppress cough. morphine also acts on the hypothalamus and pituitary-adrenal cortex and affects several releases of hormones.