DSIP (Delta Sleep-Inducing Peptide) is a neuropeptide first isolated from rabbit brain tissue in 1977. This nonapeptide has been extensively studied for its effects on sleep architecture, particularly its ability to promote delta wave sleep patterns. Research indicates DSIP may influence the hypothalamic-pituitary axis and modulate stress hormone levels. Studies have examined its potential effects on circadian rhythm regulation, stress adaptation, and neuroendocrine function. DSIP represents an important research compound for understanding sleep physiology and stress response mechanisms.