DSIP (Delta Sleep-Inducing Peptide)

DSIP, or delta sleep-inducing peptide, is a nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu and a molecular weight of 848.81 g/mol. It was first isolated in the 1970s by Schoenenberger and Monnier from the cerebral venous blood of rabbits during electrically induced delta-wave sleep — an origin that gave the peptide both its name and its long association with sleep-architecture research.

Published work on the nonapeptide spans EEG delta-activity recording and sleep-architecture measurement, corticotropin and stress-axis studies, thermoregulation and withdrawal models, much of it European and much of it from the two decades following the peptide's isolation. Interpretation has always been complicated by the short plasma persistence reported for the molecule. That instability shapes bench practice more than the storage table suggests: solutions are held at 2–8 °C, aliquoted rather than thawed repeatedly, and made up close to the time of use, because both the aspartate-glycine motif and the N-terminal tryptophan give the sequence ready chemical routes to degrade in water. Vials are offered at 5 mg and 10 mg, and a multi-arm series normally takes the larger fill so the whole study stays on one lot number.

Reconstitution is where the arithmetic lives. The same vial made up with 1 mL or with 3 mL of diluent gives three-fold different numbers, which is why a reconstitution volume calculator is more use here than a fixed table: enter the vial mass and your diluent volume and read the concentration back.

If the protocol asks for a molar concentration, the molar concentration calculator converts between 848.81 g/mol, the mass you weigh out and the volume you dissolve it in.