endorphins and enkephalins are neuropeptides that?
Endorphins and Enkephalins Endorphins, enkephalins, and dynorphin are powerful peptide or polypeptide analgesics. Their analgesic action requires binding to opiate receptors on nerve cells. ... Enkephalins act to attenuate substance P release in the dorsal horn of the spinal cord and inhibit afferent pain fibers.