Characterization of a delta-electroencephalogram (-sleep)-inducing peptide.

Open Access
Publisher Website
Google Scholar
Abstract
A peptide that induced a slow-wave (.delta.) and spindles EEG after intraventricular (brain) infusion was isolated from rabbits and given the name .delta.-sleep-inducing peptide (DSIP). The amino acid sequence was: Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. This compound, 5 possible metabolic products (containing residues 1-8, 2-9, 2-8, 1-4 and 5-9), 2 nonapeptide analogues with 2 amino acids exchanged and a related tripeptide (Trp-Ser-Glu) were synthesized. All 9 synthetic peptides were infused intraventricularly in rabbits under double-blind conditions. A total of 58 rabbits including controls were evaluated. The EEG leads from the neocortex and the archicortex were directly fast-Fourier transformed and analyzed by a Univac 1108 computer system. Only the DSIP (synthetic) showed significant and specific enhancement or induction of .delta. and spindle EEG patterns.