Characterization of a delta-electroencephalogram (-sleep)-inducing peptide. — VialBase Research

Summary

This is the origin paper for DSIP. Schoenenberger and Monnier isolated from rabbits a peptide that induces slow-wave (delta) and spindle electroencephalogram enhancement after intraventricular (brain) infusion, and gave it the name delta-sleep-inducing peptide (DSIP). They reported its amino acid sequence as Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. To test structural specificity, the group synthesized nine peptides: DSIP itself, five possible metabolic products (containing residues 1-8, 2-9, 2-8, 1-4, and 5-9), two nonapeptide analogues with two amino acids exchanged, and a related tripeptide (Trp-Ser-Glu). All nine were infused intraventricularly in rabbits under double-blind conditions, with a total of 58 rabbits including controls evaluated. Electroencephalogram leads from the neocortex and the archicortex were directly fast-Fourier transformed and analyzed by a Univac 1108 computer system. Of the nine synthetic peptides tested, only synthetic DSIP showed significant and specific enhancement/induction of delta and spindle electroencephalogram patterns. The finding is a specific EEG signature in an animal model under direct intracerebroventricular delivery — the paper does not test oral, subcutaneous, or intravenous administration, does not measure behavioral sleep outcomes, and does not involve human subjects.

Key Findings

• A peptide enhancing slow-wave (delta) and spindle EEG activity after intraventricular brain infusion was isolated from rabbits and named delta-sleep-inducing peptide (DSIP)
• Amino acid sequence reported as Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu — a nonapeptide structurally unlike other known peptide families
• Nine peptides synthesized and compared: DSIP, five possible metabolic fragments (residues 1-8, 2-9, 2-8, 1-4, 5-9), two nonapeptide analogues with two amino acid substitutions, and the related tripeptide Trp-Ser-Glu
• All nine were infused intraventricularly into rabbits under double-blind conditions; 58 rabbits including controls were evaluated, with neocortical and archicortical EEG leads fast-Fourier transformed and computer-analyzed
• Only synthetic DSIP produced significant and specific delta/spindle EEG enhancement — the fragments, substituted analogues, and tripeptide did not, suggesting the intact nonapeptide sequence was required for the observed effect

Relevance to DSIP

Anyone researching DSIP should recognize this paper as the single source from which the peptide’s entire reputation as a “sleep peptide” descends — the name itself was assigned here, in 1977, on the basis of a rabbit EEG signature. That matters for how much weight the name can carry. The effect demonstrated is narrow and specific: delta and spindle EEG enhancement in rabbits after direct intraventricular infusion into the brain, under double-blind conditions, with structure-activity controls showing the intact nonapeptide was required. What the paper does not show is any effect in humans, any effect by a peripheral route of administration such as subcutaneous or intravenous injection, or any measured improvement in sleep quality, sleep continuity, or daytime function. Treat this as the historical anchor of the DSIP literature rather than as evidence of consumer-relevant benefit, and read it alongside the later critical review by Kovalzon and Strekalova, which argues the DSIP-sleep link was never adequately characterized after this paper.

Citation

Schoenenberger GA, Monnier M. Characterization of a delta-electroencephalogram (-sleep)-inducing peptide. Proceedings of the National Academy of Sciences of the United States of America. 1977;74(3):1282-6. doi:10.1073/pnas.74.3.1282.

See Also

• Parent compound: DSIP