DSIP

Also known as: Delta sleep-inducing peptide, Deltaran (Russian preparation)

Evidence: Clinical

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Overview

Endogenous nonapeptide first isolated from rabbit brain; older, small human studies looked at sleep onset, stress-axis normalization and chronic pain.

DSIP is a nonapeptide isolated in 1977 from rabbit cerebral venous blood, named for the delta electroencephalogram enhancement it produced on intraventricular infusion (Schoenenberger and Monnier, 1977). Human work is small, intravenous and four decades old: double-blind studies in chronic insomniacs reported sleep normalisation and better daytime performance (Schneider-Helmert, 1986), while a controlled parallel-group trial found the effects weak and concluded short-term treatment was unlikely to help much (Bes et al., 1992). An open pilot reported lower pain scores in 7 patients with chronic pain (Larbig et al., 1984). No DSIP gene, precursor or receptor has been identified, and a review by researchers in the field treats the sleep hypothesis as unresolved (Kovalzon and Strekalova, 2006). Measured half-life is minutes.

Benefits

Improved sleep quality, stress reduction, recovery

Dosing reference

Research dose: 100 to 200 mcg before sleep (community range; human trials used 25 to 30 nmol/kg intravenously, about 1.5 to 2 mg for a 70 kg adult)
Range: 100 to 200 mcg, 1x daily
Reconstitution: 2 mL bacteriostatic water
Common vial sizes: 5 mg

Human studies used intravenous dosing only: 25 nmol/kg before three nights (Bes et al., 1992) and 30 nmol/kg for 6 doses over a week (Schneider-Helmert, 1986), with slow injection described as necessary (Schneider-Helmert and Schoenenberger, 1983). Those doses are about 1.5 to 2 mg for a 70 kg adult, roughly ten times the 100 to 200 mcg subcutaneous range used in the research community, which no study has tested. Measured half-life is minutes in dog, monkey and rat, and the peptide is degraded in blood (Kato et al., 1984). One small study used the intranasal route (PMID 11763019).

Mechanism

DSIP is the nonapeptide Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, isolated in 1977 from cerebral venous blood of rabbits whose electroencephalogram showed delta enhancement after intraventricular infusion (Schoenenberger and Monnier, 1977). No DSIP gene, precursor protein or receptor has ever been identified, which is why its own reviewers call the sleep-factor hypothesis poorly documented and propose that the activity belongs to an unidentified DSIP-like peptide (Kovalzon and Strekalova, 2006). Reported actions in rodents include effects on glutamate and GABA receptor currents in cortex, hippocampus and cerebellum, and anticonvulsant activity. Blood-brain barrier passage has been measured in guinea pig and dog preparations. The peptide is degraded rapidly in blood, with tryptophan-containing fragments appearing within minutes.

Evidence

Clinical: at least one published human trial or an approved drug

Isolated from rabbit cerebral venous blood; intraventricular infusion enhanced delta and spindle electroencephalogram patterns in 58 rabbits, and five fragments and two analogs did not (Schoenenberger and Monnier, 1977)
Five double-blind human studies with single and repeated intravenous dosing reported sleep normalisation in insomniacs plus higher daytime alertness; slow injection was described as essential (Schneider-Helmert and Schoenenberger, 1983)
One week of intravenous dosing in 18 chronic insomniacs (6 doses at 30 nmol/kg) improved sleep toward normal values, with the effect tracking baseline severity (Schneider-Helmert, 1986)
A double-blind parallel-group trial in 16 chronic insomniacs (25 nmol/kg intravenously before three nights) found higher sleep efficiency and shorter latency, but the authors judged the effects weak and partly attributable to a shift in the placebo group (Bes et al., 1992)
An open pilot in 7 patients with chronic pain episodes reported lower pain scores after intravenous dosing on 5 consecutive days then every 48 to 72 hours (Larbig et al., 1984)
Human-trial status: the human work is small, 1980s and intravenous, with one controlled trial reporting little therapeutic benefit. No modern trial, no approval anywhere, and the field's own review calls the link between DSIP and sleep unresolved (Kovalzon and Strekalova, 2006)

References

Side effects

Reported effects are limited to injection-site irritation, headache, and next-day grogginess. Human data comes from a handful of small studies, so the safety profile is not well characterized.

Storage

Storage: Refrigerated (2-8°C)
Lyophilized: 24+ months at room temperature
Reconstituted: 28-30 days refrigerated

Pharmacology

Half-life: ~4.0 min (dog, IV; clearance 30.7 mL/kg/min), 2.9 min in a monkey and ~2.0 min in rats (Kato et al., 1984); no human figure published
Bioavailability: No bioavailability figure published for any route. Blood-brain barrier passage was measured in perfused guinea pig brain and in dog cerebrospinal fluid; intravenous peptide is degraded in blood within minutes (Kato et al., 1984).
Molecular weight: 848.81 Da
Sequence: Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu

Stacks with

Epithalon