BETA-ENDORPHIN (RAT)

Potent endogenous opioid protein that is derived from propiomelanocortin, a protein found in the brain, anterior pituitary, skin, immune system, and other peripheral sites. It is released in response to painful stimuli and has potent antinociceptive activity that is mediated through its action on μ receptors in brain and by μ and κ receptors in the spinal cord.