Passage of delta sleep-inducing peptide (DSIP) across the blood-cerebrospinal fluid barrier.
Zlokovic. B V BV; Segal. M B MB; Davson. H H; Jankov. R M RM
Key Findings
- DSIP crosses the bloodâCSF barrier with lowâtoâmoderate permeability.
- Transport follows a highâaffinity, lowâcapacity saturable mechanism (Kt â 5âŻnM, Vmax â 272âŻfmol/min).
- There is little to no active removal of intact DSIP from the CSF.
Practical Outcomes
- For biohackers, this suggests that peripheral dosing (e.g., subcutaneous) may deliver some DSIP to the brain, but the amount is limited and may require higher or more frequent dosing to achieve noticeable effects. Direct CNS delivery (e.g., intrathecal) could be more efficient, though itâs more invasive. The data also imply that once DSIP reaches the CSF, it may stay longer, potentially extending its action.
Summary
The study shows that delta sleepâinducing peptide (DSIP) can move from the bloodstream into the brain's fluid (CSF) but does so slowly and in limited amounts, and once there it doesnât get cleared quickly.
Abstract
Unidirectional flux of 125I-labeled DSIP at the blood-tissue interface of the blood-cerebrospinal fluid (CSF) barrier was studied in the perfused in situ choroid plexuses of the lateral ventricles of the sheep. Arterio-venous loss of 125I-radioactivity suggested a low-to-moderate permeability of the choroid epithelium to the intact peptide from the blood side. A saturable mechanism with Michaelis-Menten type kinetics with high affinity and very low capacity (approximate values: Kt = 5.0 +/- 0.4 nM; Vmax = 272 +/- 10 fmol.min-1) was demonstrated at the blood-tissue interface of the choroid plexus. The clearance of DSIP from the ventricles during ventriculo-cisternal perfusion in the rabbit indicated no significant flux of the intact peptide out of the CSF. The results suggest that DSIP crosses the blood-CSF barrier, while the system lacks the specific mechanisms for removal from the CSF found with most, if not all, amino acids and several peptides.
Study Information
pubmed
1988
10.1016/0196-9781(88)90160-x