DSIP (Delta Sleep Inducing Peptide)

DSIP (Delta Sleep Inducing Peptide) is a nonapeptide (Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) first isolated from rabbit cerebral venous blood by Monnier, Schoenenberger and colleagues in 1977. The peptide was identified through bioassay-guided fractionation of venous blood from electrically stimulated thalamic nuclei — the procedure that induces slow-wave delta sleep in rabbits — with activity attributed to a fraction subsequently sequenced as DSIP. Despite nearly five decades of published research across sleep biology, stress physiology, antioxidant chemistry, and ageing research, DSIP remains scientifically distinctive in that neither its endogenous biosynthetic gene, its specific receptor, nor its complete mechanism of action has been definitively characterised.

The peptide's pharmacological stability — greater resistance to degradation than most nonapeptides — has been attributed to the absence of optimal cleavage sites for common endopeptidases and the compact structure produced by its Gly-rich backbone. DSIP has been documented to cross the blood-brain barrier in published animal model studies, though the specific transport mechanism has not been definitively characterised. These practical stability and CNS-access properties make DSIP a useful research tool for studies requiring a neuroactive peptide with reasonable duration of action in biological systems.

Sleep architecture research with DSIP uses EEG recording in rodent models to characterise changes in slow-wave (delta, 0.5-4 Hz) sleep power, rapid eye movement sleep duration, and sleep-wake cycle regularity under controlled light-dark conditions. Published research has examined dose-dependence, light-phase versus dark-phase administration timing, and comparison with established pharmacological sleep modifiers. The mechanistic hypothesis for DSIP's EEG effects has focused on NMDA receptor modulation and MAPK/ERK cascade inhibition — a proposed GILZ (glucocorticoid-induced leucine zipper) structural homology suggests DSIP may inhibit the Raf-MEK-ERK cascade, with downstream effects on neuronal excitability relevant to sleep state regulation.

HPA axis research with DSIP has examined cortisol and corticosterone secretion dynamics across multiple species. Published data suggests DSIP normalises hypercorticism under stress conditions without producing absolute adrenocortical suppression — a regulatory rather than inhibitory HPA effect. This distinguishes DSIP from glucocorticoid receptor antagonists or adrenal-suppressing compounds, positioning it as a potential tool for studying the mechanisms of HPA axis homeostasis and stress response normalisation.

Antioxidant research has characterised DSIP as a free radical scavenger in multiple biochemical assay systems: DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid), and hydroxyl radical scavenging using Fenton reaction-generated OH·. Published data from Khavinson's institute in St. Petersburg has examined cytoprotective effects in cell models under H2O2-induced oxidative stress, and anti-ageing research has examined DSIP alongside Epithalon and other bioregulator peptides in telomere length and cellular lifespan experiments.

MW: 848.84 g/mol. CAS: 62568-57-4. Molecular formula: C35H48N10O15. Contains tryptophan — protect from UV light. Reconstitute in bacteriostatic water at 1mg/mL. Store lyophilised at -20°C in amber container. For laboratory and analytical research purposes only.

Practical research notes: DSIP contains tryptophan at position 1, making it photosensitive. Protect from UV exposure throughout all experimental procedures — use amber containers, work under dim light when handling reconstituted solutions. DSIP is relatively stable in aqueous solution at pH 7.0-7.4 at 4°C for several weeks. For long-duration experiments, prepare fresh stocks weekly. Plasma stability is substantially better than most nonapeptides, consistent with published data showing DSIP maintains detectable concentrations in plasma for 30+ minutes after administration. MW: 848.84 g/mol. CAS: 62568-57-4. Reconstitute in bacteriostatic water at 1mg/mL. Store lyophilised at -20°C, amber container. For laboratory and analytical research purposes only.