DSIP--a tool for investigating the sleep onset mechanism: a review.

Delta-Sleep-Inducing Peptide (DSIP) has several physiological effects in addition to its ability to promote sleep in animals under certain conditions. These effects include modification in thermoregulation, heart rate, blood pressure, pain threshold, and in the lymphokine system. DSIP effects are circadian cycle-dependent. Moreover, some of DSIP effects appear before neurological or behavioral signs of sleep. DSIP may promote peripheral preparatory physiological mechanisms associated with sleep onset.