Endorphins
They are produced by the central nervous system and the pituitary gland. Their name has two parts: endo- and -orphin; these are short forms of the words endogenous and morphine. They mean "a morphine-like substance from within the body". Endorphins are three compounds which bind to receptors. The main function of endorphins is to inhibit the communication of pain signals. They may also produce a feeling of euphoria very similar to that produced by other opioids.