Discovery

DSIP was isolated by Monnier, Schoenenberger and colleagues at the University of Basel in 1977 through a classic neurophysiology experiment: blood taken from the cerebral venous sinuses of rabbits during electrically induced delta sleep, concentrated, and infused into recipient animals. The recipients subsequently showed increased slow-wave EEG activity — and the responsible factor turned out to be this nine-residue peptide.

That isolation method is part of what makes DSIP a historically interesting but mechanistically awkward target: the discovery predated molecular receptor pharmacology, and decades later the primary receptor remains uncharacterised.

Research profile

Graf and Kastin's 1984 review in Neuroscience and Biobehavioral Reviews remains the most comprehensive summary of DSIP's preclinical profile. Reported effects include:

• Modulation of delta-wave sleep EEG in rodent models.
• Anti-stress effects in a variety of physical and psychological stress paradigms.
• Endocrine effects on cortisol, ACTH, and somatotropin release in some protocols.
• Anti-nociceptive effects in certain pain models.

The persistent challenge is the absence of a confirmed receptor — which makes dose-response work difficult and means mechanistic claims rely on downstream readouts rather than direct pharmacology.

Storage

Store lyophilised DSIP at −20°C protected from light. Reconstituted peptide is stable refrigerated at 2–8°C for approximately 2–4 weeks.