Delta sleep-inducing peptide (DSIP) is a naturally occurring substance, which was originally isolated from rabbit brain in 1977. This peptide is a nonapeptide that is normally synthesized in the hypothalamus and targets multiple sites including some within the brain stem. As its name suggests DSIP promotes sleep and this has been demonstrated in rabbits, mice, rats, cats and human beings. In fact, DSIP promotes a particular type of sleep which is characterized by an increase in the delta rhythm of the EEG.
Clinical uses for DSIP already exist. The agent has been used for the treatment of alcohol and opioid withdrawal with some success. Clinical symptoms and signs disappear after injection of DSIP although some patients have reported occasional headaches. It may also reduce amphetamine-induced hyperthermia and may be beneficial in some chronic pain conditions. It may also have future applications in cancer treatment, depression, and prevention of free radical damage.