Encyclopedia

DSIP (delta sleep-inducing peptide) is a naturally occurring nonapeptide first isolated from the cerebral venous blood of sleeping rabbits, associated with slow-wave (delta) EEG activity. It is found endogenously in human plasma and tissues, with levels correlated to circadian rhythm. Its gene, precursor, and receptor have never been identified, and modern reproducibility of its original sleep-inducing effects is limited. It is not FDA-approved.</br>

DSIP has the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE), isolated and characterized by Schoenenberger and Monnier in 1977 after intraventricular infusion into rabbits produced spindle and delta EEG activity with reduced motor activity. Despite the name, its role as a genuine physiological sleep regulator remains scientifically unresolved -- no gene, precursor protein, or dedicated receptor has been identified in the four decades since its discovery, and a substantial review literature (Graf & Kastin 1984; Kovalzon & Strekalova 2006) treats it as 'a still unresolved riddle.' Beyond sleep, DSIP has been studied preclinically for anticonvulsant activity (potentiating valproate in an epilepsy model), analgesic effects via modulation of enkephalin-opioid receptor interactions, and neuroprotection in models of toxic cerebral edema. It crosses the blood-brain barrier and is also absorbed from the gut. It is sold as a research chemical with no approved human indication.

Mechanism of Action

Mechanism is not well characterized; DSIP has no confirmed dedicated receptor. Proposed activities include modulation of GABAergic and opioid (enkephalin) signaling, effects on the hypothalamic-pituitary axis, and correlation with circadian rhythm and stress-hormone regulation. Structural similarity to dermorphin (a mu-opioid agonist) has been noted but DSIP's own receptor pharmacology remains unresolved.