Definition An endorphin (from the abbreviation endogenous morphine) is a , that is to say a [ tooltip title=”A peptide is a polymer of amino acids linked together by peptide bonds”]peptide[/tooltip] acting as a neurotransmitter,
Definition Opioid receptors are receptors located in the cell membrane coupled with G proteins having as ligand an opioid (derived from the word opium). Description There are 4 subtypes of opioid receptors: Delta (δ) Kappa