The delta sleep inducing peptide (DSIP). Isolation, structure, and properties of the original sleep promoting substance

Summary

This seminal study reported the original isolation, structural characterization, and sleep-promoting properties of Delta Sleep-Inducing Peptide (DSIP), a nonapeptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) purified from cerebral venous blood of rabbits during electrically induced sleep. DSIP was shown to selectively enhance delta wave (slow-wave) sleep when administered to recipient animals.

Key Findings

• DSIP was isolated from the cerebral venous blood of rabbits during electrically induced sleep and identified as a nonapeptide with the sequence Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu
• Intraventricular or intravenous administration of DSIP to recipient rabbits selectively increased delta wave (stage 3-4) sleep without significantly altering total sleep time or REM sleep
• The sleep-promoting effect was dose-dependent and occurred at nanomolar concentrations, with maximal effects observed 1-2 hours after administration