Glossary
Delta Sleep-Inducing Peptide (DSIP)
DSIP is the nonapeptide WAGGDASGE, isolated in 1977 from rabbit cerebral venous blood. Its sequence, the missing-receptor problem and its research context.
Delta sleep-inducing peptide, or DSIP, is a nine-residue peptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu (WAGGDASGE) and a molecular weight of about 848 Da. Schoenenberger and Monnier isolated it in 1977 from the cerebral venous blood of rabbits kept in electrically induced sleep; its name reflects the rise in delta-wave EEG activity reported after the fraction was given to recipient animals.
An unusual glossary entry
Almost half a century on, nobody has cloned or confirmed a DSIP receptor, and no gene coding for a DSIP precursor has been found — awkward for a molecule whose name implies a clear mechanism. The activity described in the literature is wide-ranging and varies between studies: EEG changes, effects on ACTH and somatostatin release, and antioxidant endpoints have all been reported, largely in small rodent experiments plus a few small human case series from the 1980s.
DSIP is also cleared rapidly and is very vulnerable to proteolysis, and its acidic residues turn solution pH into a genuine handling factor. Catalogues group it with nootropic and sleep-related material; the accurate description is a research peptide of historical importance whose mechanism is still unresolved — not a sleep agent.
Related terms and material
somatostatin · half-life · linear peptide. Reference material: DSIP, sleep & stress peptides. Further reading: what is DSIP and DSIP vs melatonin.