beta-endorphin is a potent analgesic agent.

beta-Endorphin, an opiate-like peptide, has potent antinociceptive properties when it is administered directly into the brain and assayed in the the tail-flick, hot-plate, and writhing tests in mice and in the wet shake test in rats. On a molar basis, beta-endorphin is 18 to 33 times more potent than morphine and its actions are blocked by the specific opiate antagonist, naloxone hydrochloride. The activity of beta-endorphin in vivo is also compared to other peptides that show opiate-like activity in assays in vitro.