ABSTRACT
Various biomolecules, for example proteins, peptides etc., entrapped in polymer matrices, impact interactions between matrix and cells, including stimulation of cell adhesion and proliferation. Delta-sleep inducing peptide (DSIP) possesses numerous beneficial properties, including its abilities in burn treatment and neuronal protection. DSIP entrapment in two macroporous polymer matrices based on copolymer of dimethylaminoethyl methacrylate and methylen-bis-acrylamide (Co-DMAEMA-MBAA) and copolymer of acrylic acid and methylen-bis-acrylamide (Co-AA-MBAA) has been studied. Quite 100% of DSIP has been entrapped into positively charged Co-DMAEMA-MBAA matrix, while the quantity of DSIP adsorbed on negatively charged Co-AA-MBAA was only 2-6%. DSIP release from Co-DMAEMA-MBAA was observed in saline solutions (0.9% NaCl and PBS) while there was no DSIP release in water or 25% ethanol, thus ionic strength was a reason of this process.
Subject(s)
Acrylamides/chemistry , Delta Sleep-Inducing Peptide/isolation & purification , Delta Sleep-Inducing Peptide/pharmacokinetics , Methacrylates/chemistry , Polymers/chemistry , Adsorption , Delta Sleep-Inducing Peptide/chemistry , Hydrogel, Polyethylene Glycol Dimethacrylate , Hydrogen-Ion Concentration , Materials Testing , Porosity , Sodium ChlorideABSTRACT
Quantitative shifts in the content of interleukine-1, -2 and -6 of the myocardium of mice under the conditions of acoustic stress and delta-sleep inducing peptide action are studied. It has been shown that injection of delta-sleep inducing peptide has no effect on the level of interleukine-1 and -2 in the myocardial tissue, whereas the quantity of interleukine-6 increased. The level of interleukine-1- and -6 in the myocardium were increased and no significant changes were observed in the level of interleukine-2 under the noise action. Interleukine-1- and -2 were not detected in the hypophysis of experimental animals of all groups (intact, under acoustic stress, under delta-sleep inducing peptide application). The level of interleukine-6 in the hypothalamus decreased under conditions of acoustic stress, whereas administration of delta-sleep inducing peptide has no effect on its level. The obtained data are considered in the context of immune modulating properties of delta-sleep inducing peptide.
Subject(s)
Delta Sleep-Inducing Peptide/pharmacokinetics , Heart Failure/immunology , Interleukin-1/immunology , Interleukin-2/immunology , Interleukin-6/immunology , Myocardium/immunology , Myocardium/metabolism , Noise/adverse effects , Sleep Stages/physiology , Animals , Delta Sleep-Inducing Peptide/administration & dosage , Mice , Pituitary Gland/immunology , Pituitary Gland/metabolismABSTRACT
Delta sleep-inducing peptide (DSIP), a peptide of nine amino acid residues, was used as a model drug to investigate the effects of pH, electric current, and enzyme inhibitors on the transdermal iontophoretic delivery of peptide drugs. DSIP was fairly stable in pH 4-9 buffer solutions but was cleaved by the skin enzymes during iontophoretic delivery. Enzyme inhibitors, such as o-phenanthroline, ethylene-diaminetetraacetic acid (EDTA), dilucine, and sodium deoxycholate, could inhibit the degradation of DSIP to a certain extent in the skin homogenate. Our results showed that metalloproteases were probably more important enzymes for DSIP hydrolysis. By using 0.2 mM o-phenanthroline in the iontophoretic delivery of DSIP at pH 4, we were able to significantly enhance the penetration of DSIP. The flux was about eight times as much as control (without o-phenanthroline) at pH 7.4.
Subject(s)
Delta Sleep-Inducing Peptide/administration & dosage , Iontophoresis/methods , Administration, Cutaneous , Animals , Delta Sleep-Inducing Peptide/pharmacokinetics , Drug Delivery Systems , Drug Stability , Electricity , Evaluation Studies as Topic , Female , Hydrogen-Ion Concentration , In Vitro Techniques , Male , Metalloendopeptidases/antagonists & inhibitors , Phenanthrolines/administration & dosage , Protease Inhibitors/administration & dosage , Rabbits , Skin/drug effects , Skin/metabolismABSTRACT
The diffusion of delta sleep-inducing peptide (DSIP) across the blood-brain barrier (BBB) has been investigated with an in-vitro model comprised of primary cultures of brain microvessel endothelial cell (BMEC) monolayers. The BMEC monolayers were mounted in a side-by-side diffusion apparatus and the transendothelial flux of DSIP analysed by HPLC with UV detection at 280 nm. The transendothelial flux of the peptide was linear with time and increasing concentrations of DSIP (non-saturable), but was not altered by reduced temperature. The apparent permeability coefficient for DSIP penetration of BMEC monolayers was in a range similar to water-soluble substances (e.g. fluorescein, fluorescein isothiocyanate dextrans) that penetrate the blood-brain barrier to a limited degree based on molecular weight. DSIP flux across the BMEC monolayers was also found to be bidirectional, insensitive to metabolic inhibitors, and not altered by high concentrations of tryptophan. Little degradation (apparent t1/2 about 10 h) of DSIP to major metabolites, tryptophan (trp) and des-trp DSIP, occurred over the time of the diffusion experiments. The results of these studies support and confirm observations in-vivo indicating that intact DSIP crosses the BBB by simple transmembrane diffusion.
Subject(s)
Blood-Brain Barrier , Delta Sleep-Inducing Peptide/pharmacokinetics , Animals , Cattle , Cells, Cultured , Diffusion , In Vitro Techniques , Membranes, Artificial , Molecular Weight , Permeability , Temperature , Tryptophan/pharmacokineticsABSTRACT
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.
Subject(s)
Brain/metabolism , Delta Sleep-Inducing Peptide/pharmacokinetics , Animals , Choroid Plexus/metabolism , Delta Sleep-Inducing Peptide/blood , Delta Sleep-Inducing Peptide/cerebrospinal fluid , Female , Iodine Radioisotopes , Kinetics , Male , Organ Specificity , Permeability , SheepABSTRACT
Delta sleep inducing peptide (DSIP) significantly increases deep-slow-wave sleep (DSWS) of cats after subcutaneous (SC) injection. Cats (n = 8) were SC injected with DSIP (120 nmol.kg-1) prior to polygraphic recording of EEG combined with electro-oculography, EOG) and electromyography (EMG) for 8 hours. DSIP was found to significantly increase slow-waves (delta sleep) in the sleep EEG. There was a tendency to reduced waking time and a prolongation of slow wave sleep time, and a shortening of sleep onset and REM sleep latencies but the differences from control (Ringer injection) were not statistically significant. There was no change in the amount of REM sleep. These findings support the belief that DSIP can increase sleep wave activity when administered by peripheral route.
