Opioid peptides in the brain.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002417:Cattle; D004723:Endorphins / Q000378:metabolism*; D004745:Enkephalins / Q000378:metabolism; D006801:Humans; D011957:Receptors, Opioid / Q000378:metabolism; D013552:Swine
D004723:Endorphins; D004745:Enkephalins; D011957:Receptors, Opioid