DSIP is the nonapeptide Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, an anionic, all-L sequence with a free C-terminal carboxylate and no disulfide or other modification. It was isolated in the 1970s from cerebral venous blood of rabbits during electrically induced slow-wave electroencephalographic states and named delta sleep-inducing peptide; the nonapeptide structure was established by amino-acid analysis and confirmed by total synthesis. It is also indexed as emideltide.

No receptor has been established for it. Reviews of the molecular literature describe DSIP as a peptide of unresolved molecular target, with immunoreactive DSIP-like material detected in brain and pineal extracts and a larger leucine-zipper-containing brain protein recognised by DSIP antisera, raising the question of precursor or cross-reactive relationships.

Cited in neuropeptide chemistry, immunoassay and antiserum characterisation, peptide degradation and aggregation studies in plasma and serum incubations, and comparative analog synthesis. Supplied as a lyophilized solid.

Research use only. This material is sold for in-vitro laboratory research and development purposes exclusively. It is not a drug, food, or dietary supplement, has not been evaluated by the FDA, and must not be used in humans or animals.