1) Opioid peptide 
Adrenorphin, also sometimes referred to as metorphamide, is an endogenous, C-terminally amidated, opioid octapeptide (Tyr-Gly-Gly-Phe-Met-Arg-Arg-Val-NH2) that is produced from proteolytic cleavage of proenkephalin A and is widely distributed throughout the mammalian brain. It was named based on the fact that it was originally detected in human ph...