Opioid peptides as intercellular messengers.
Opioid peptides are endogenous substances present in central nervous system and various tissues whose actions are mediated by opiate receptors. They belong to two different classes: short peptides like the two pentapeptides enkephalin and substances of higher molecular weight like beta-endorphin. It appears that these various peptides play a messenger role between cells, either as neurotransmitters in the case of enkephalins or as hormones in the case of beta-endorphin.
D000818:Animals; D002490:Central Nervous System / Q000378:metabolism; D004723:Endorphins / Q000502:physiology*; D004745:Enkephalins / Q000378:metabolism / Q000502:physiology; D018377:Neurotransmitter Agents; D010902:Pituitary Gland / Q000378:metabolism; D010907:Pituitary Hormones; D011957:Receptors, Opioid / Q000378:metabolism
D004723:Endorphins; D004745:Enkephalins; D018377:Neurotransmitter Agents; D010907:Pituitary Hormones; D011957:Receptors, Opioid