DSIP

DSIP, delta sleep-inducing peptide, is a nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. Its molecular formula is C35H48N10O15, its molecular weight 848.8 g/mol, its CAS number 62568-57-4, and its PubChem CID 68816. The chain is unusually acidic for a neuropeptide, carrying an aspartate residue, a C-terminal glutamate and a free carboxyl terminus, and it has no cysteine and therefore no disulfide bridge. Tryptophan at position one is its only aromatic residue. The World Health Organization assigned it the International Nonproprietary Name emideltide. DSIP is supplied here as lyophilized (freeze-dried) reference material for laboratory research use only.

The compound name records the experimental setting in which the peptide was isolated and is not a pharmacological classification. DSIP belongs to no previously described peptide family and its structure is distinct from other characterised neuropeptides. No dedicated DSIP receptor has been cloned and the gene encoding a DSIP precursor protein has not been isolated, which is why the literature reports circulating material as DSIP-like immunoreactivity rather than a single confirmed peptide. It is catalogued as a neuropeptide by origin, not by a defined receptor interaction. DSIP holds no regulatory approval in any jurisdiction.

DSIP was isolated in 1977 by the Schoenenberger and Monnier group at the University of Basel, and its name derives from the electrophysiological work that produced it. Dialysed cerebral venous blood from rabbits under low-frequency thalamic stimulation was infused into recipient rabbits, which then showed increased delta-band and spindle activity on the electroencephalogram (PubMed 265572).

The literature that followed is broad and largely preclinical. Graf and Kastin reviewed the field in 1984 (PubMed 6145137). Kovalzon and Strekalova revisited it in 2006 and called the peptide an unresolved problem rather than a characterised signalling molecule (PubMed 16539679). Bobyntsev and colleagues reported hepatocyte measures in restrained rats in 2016 (PubMed 26902351).

The evidence base is old, wide and thin at once. Nearly five decades of work have produced no cloned receptor, no precursor gene, and findings that vary between species and assay formats. No human outcome is stated or implied here.

Because no dedicated receptor has been identified, published mechanisms for DSIP are inferred from neurochemical experiments rather than direct receptor binding data. In vitro work on rat brainstem slices and synaptosomes reports calcium-dependent release of immunoreactive Met-enkephalin, while DSIP itself does not bind appreciably to characterised opioid receptors. Animal-model reports also describe changed corticotropin and corticosterone measurements under experimental stress.

One distinction is worth flagging. DSIP is a separate entity from phosphorylated DSIP, written P-DSIP, which has its own reported profile in animal work, and secondary sources routinely conflate the two.

A methodology caveat is central rather than incidental. Much of the record rests on radioimmunoassay with polyclonal antisera that may cross-react with related fragments, and on species that differ physiologically.

Sealed lyophilized DSIP is stored at -20°C, shielded from light, in the unopened vial. No duration is given here: the stability window for a batch is documented on its Certificate of Analysis.

Lyophilized peptide is hygroscopic, meaning it takes up atmospheric moisture. Freeze-thaw cycling of stock material is avoided. The aspartate residue, serine hydroxyl and N-terminal tryptophan make the sequence sensitive to elevated temperature and to extremes of pH.

Reconstitution is the term for returning a lyophilized compound to solution; this page defines the term and gives no procedure. DSIP is a short, highly polar, acidic sequence in the aqueous solubility class.

Solid material is handled in low humidity with minimal open-container exposure. Peptides of this length adsorb to some plastic and glass surfaces at low concentration, a recognised source of apparent loss. Preparation parameters belong to the published methodology being reproduced, read with the lot COA.

Identity and purity for a nonapeptide are established by high-performance liquid chromatography with ultraviolet detection and mass spectrometry. The primary identity check is a mass consistent with 848.8 g/mol and a formula matching C35H48N10O15. Verified purity is documented per lot on the Certificate of Analysis.

Two impurity questions are specific here. Aspartate-containing chains can form aspartimide and isoaspartate variants during synthesis, and the tryptophan is prone to oxidation. Counter-ion content and residual water also affect the ratio of vial fill weight to net peptide, a value recorded on the COA.

DSIP is catalogued alongside other short regulatory peptides studied in central nervous system models.

• Semax.
  A synthetic ACTH(4-10) analogue studied in rodent central nervous system models, the closest catalogue neighbour by research context, not structure.
• Selank.
  A tuftsin analogue investigated in animal models of anxiety-related behaviour, a short peptide with a defined parent sequence, which DSIP lacks.
• Epitalon.
  A synthetic tetrapeptide investigated in animal models for pineal and telomere-associated pathways, often grouped with DSIP but unrelated.
• N-Acetyl Semax and N-Acetyl Selank (entries forthcoming). Acetylated variants of the two peptides above, studied as stability-modified forms.
• P21.
  A ciliary neurotrophic factor derived peptidomimetic, a designed molecule with a known parent, unlike DSIP.

Schoenenberger GA, Monnier M (1977). Characterization of a delta-electroencephalogram (-sleep)-inducing peptide. Proc Natl Acad Sci U S A.
PubMed 265572

Graf MV, Kastin AJ (1984). Delta-sleep-inducing peptide (DSIP): a review. Neurosci Biobehav Rev.
PubMed 6145137

Graf MV, Kastin AJ (1986). Delta-sleep-inducing peptide (DSIP): an update. Peptides.
PubMed 3550726

Kovalzon VM, Strekalova TV (2006). Delta sleep-inducing peptide (DSIP): a still unresolved riddle. J Neurochem.
PubMed 16539679

Bobyntsev II, Kryukov AA, et al. (2016). Effect of delta sleep-inducing peptide on functional state of hepatocytes in rats during restraint stress. Bull Exp Biol Med.
PubMed 26902351

DSIP is stocked in one format, a lyophilized research vial, from a single brand at a listed 5mg fill, in black glass with a gold cap. There is no capsule or liquid spray listing at present. The fill weight is a product specification, not an amount to administer. Each vial ships with a published Certificate of Analysis.

• Browse all DSIP research products
• Real Peptides DSIP, 5mg research vial
• Collections: Research Vials. Documentation: COA and Lab Testing.

These products are sold for Research Use Only and are not intended for human consumption.