Delta Sleep-Inducing Peptide Recovers Motor Function in SD Rats after Focal Stroke.

Background and Objectives: Mutual effect of the preliminary and therapeutic intranasal treatment of SD rats with DSIP (8 days) on the outcome of focal stroke, induced with intraluminal middle cerebral occlusion (MCAO), was investigated. Materials and Methods: The groups were the following: MCAO + vehicle, MCAO + DSIP, and SHAM-operated. DSIP or vehicle was applied nasally 60 (±15) minutes prior to the occlusion and for 7 days after reperfusion at dose 120 µg/kg. The battery of behavioral tests was performed on 1, 3, 7, 14, and 21 days after MCAO. Motor coordination and balance and bilateral asymmetry were tested. At the end of the study, animals were euthanized, and their brains were perfused, serial cryoslices were made, and infarction volume in them was calculated. Results: Although brain infarction in DSIP-treated animals was smaller than in vehicle-treated animals, the difference was not significant. However, motor performance in the rotarod test significantly recovered in DSIP-treated animals. Conclusions: Intranasal administration of DSIP in the course of 8 days leads to accelerated recovery of motor functions.

Phosphorylated delta sleep inducing peptide restores spatial memory and p-CREB expression by improving sleep architecture at high altitude.

AIMS: Sleep loss at high altitude (HA) play major role in worsening of neuropsychological functions, such as attention, memory and decision making. This study investigates the role of phosphorylated delta sleep inducing peptide (p-DSIP) in improving sleep architecture during chronic hypobaric hypoxia (HH) exposure and restoration of spatial navigational memory. METHODS: Morris water maze (MWM) trained rats were exposed to HH at 7620 m. p-DSIP was injected intra-peritoneally (10 µg/Kg bw) during HH exposure as an intervention against sleep alteration. Sleep architecture was recorded telemetrically before and during HH exposure. Monoamines were estimated by high performance liquid chromatography from brain stem (BS) and hypothalamus. CREB and p-CREB level in hippocampus was studied by western blotting and expression of different monoamine regulatory enzymes in BS was measured by flow cytometry. Naloxone (1 mg/kg bw), a µ opioid receptor antagonist of sleep inducing effect of DSIP was also studied. KEY FINDINGS: p-DSIP injection daily in circadian active period (18.30 h) during chronic HH enhanced non rapid eye movement sleep, rapid eye movement sleep as well as improved MWM performance of rats. p-DSIP treatment showed lower monoamine level and tyrosine hydroxylase (TH) expression and increased monoamine oxidase A (MAO A), glutamic acid decarboxylase (GAD) and Choline acetyltransferase (ChAT) expression. Further, naloxone altered navigational memory by decreasing the CREB and p-CREB level in hippocampus suggesting suppression of sleep inducing effect of p-DSIP. SIGNIFICANCE: Our study demonstrates that improvement of sleep quality by p-DSIP restores spatial memory by up regulating CREB phosphorylation during simulated high altitude hypoxia.

Effect of Delta Sleep-Inducing Peptide on Functional State of Hepatocytes in Rats During Restraint Stress.

We studied the effect of delta sleep-inducing peptide (40, 120, and 360 µg/kg intraperitoneally, 1 h before the experiment) on free radical oxidation in the liver, aminotransferase activity, and total serum protein content in male Wistar rats during restraint stress. Treatment with the peptide in a dose of 40 µg/kg increased catalase and superoxide dismutase (SOD) activities and malonic dialdehyde (MDA) concentration in the liver homogenate of animals subjected to acute stress. No significant changes were found after administration of this peptide in other doses. Under conditions of chronic stress, the peptide in a dose of 40 µg/kg caused the most pronounced effect. Catalase and SOD activities and MDA concentration decreased, while aminotransferase activity and protein content remained unchanged under these conditions. Administration of the peptide in a dose of 120 µg/kg was accompanied by a decrease in SOD activity and MDA concentration, increase in total protein content, and reduction of AST activity. Increasing the peptide dose to 360 µg/kg abolished its effects.

[THE INFLUENCE OF DELTA SLEEP-INDUCING PEPTIDE ON FUNCTIONAL STATE OF RATS HEPATOCYTES IN FOOT-SHOCK STRESS].

The effect of delta sleep-inducing peptide (DSIP) intraperitoneal injection in the doses of 40, 120, 360, and 1080 mcg/kg b. w. on lipid peroxidation and functional hepatocyte state in Wistar male rats subjected to acute and chronic electrical foot-shock stress was investigated. It was observed that 120 mcg/kg peptide normalized the elevation of malondialdehyde (MDA) level in the liver homogenate caused by acute foot-shock stress and also significantly decreased catalase activity in all investigated doses. In serum the injection of DSIP up to 40 mcg/kg increased aminotransferase activity. Peptide in all doses provided the normalization of protein synthetic hepatocyte function, increased catalase and superoxide dismutase activity in chronic stress. In addition malondialdehyde content in the liver homogenate was significantly decreased in the dose of 40 mcg/kg and in other cases it was significantly increased against the background of the common antioxidative activity reduction. The stress-induced increase in serum alanine aminotransferase activity was normalized by peptide administration in the doses of 120, 360, and 1080 mcg/kg.

Effect of delta sleep-inducing peptide on the expression of antioxidant enzyme genes in the brain and blood of rats during physiological aging.

Subcutaneous injections of exogenous delta sleep-inducing peptide in a dose of 100 µg/kg (monthly, 5-day courses) to rats of various age groups (2-24 months) were followed by an increase in the expression of genes for SOD 1 (Sod1) and glutathione peroxidase 1 (Gpx1) in the brain and nucleated blood cells. The expression of these genes was shown to decrease during physiological aging of the body.

[Influence of delta-sleep inducing peptide on the state of lysosomal membranes and intensity of lysosomal proteolysis in different rat tissues during physiological aging of the organism].

It is shown that subcutaneous injection of exogenous delta-sleep inducing peptide (DSIP) to rats aged 2-24 months in a dose of 100 µg/kg animal body weight by courses of 5 consecutive days per month has a stabilizing effect on the state of lysosomal membranes in rat tissues (brain, heart muscle and liver) at different ontogenetic stages, and this effect is accompanied by increasing intensity of lysosomal proteolysis in these tissues.

[Influence of delta-sleep peptide on the enzymes activity of mitochondrial electron transport chain in various rat tissues during aging of the organism].

It is shown that subcutaneous injection of exogenous delta-sleep inducing peptide (DSIP) to rats aged 2-24 months in a dose of 100 µg/kg animal body weight by courses of 5 consecutive days per month has a stabilizing effect on the NADH-dehydrogenase activity in the mitochondrial fractions of various tissues, which together with increasing capacity of the antioxidant system should reduce the production of free radicals and their adverse action on cells macromolecule, herewith the activity of succinate dehydrogenase did not change.

[Metabolic effects of delta-sleep inducing peptide during physiological aging of the organism].

Subcutaneous injection of delta-sleep inducing peptide (DSIP) to postnatal rats (aged from 2 to 24 months) during 5 consecutive days every months at a dose of 10 microg/100 g body weight favors normalization of the age-related changes in carbohydrate metabolism and shows hypoglycemic effect, as manifested by a decrease in the level of glycosylated hemoglobin in erythrocytes of test rats. The administration of DSIP in postnatal rats of different age also led to a decrease in serum total lipid level, total cholesterol level, and atherogenicity index and an increase in the level of high-density lipoprotein cholesterol.

Neuronal activity in the dorsal hippocampus after lateral hypothalamus stimulation: effects of delta-sleep-inducing peptide.

We studied central effects of delta-sleep-inducing peptide in the mechanisms of positive emotional state formation in rats. In Wistar rats preliminary tested in an open field, the reactions of 57 neurons of the dorsal hippocampus were analyzed during lateral hypothalamus stimulation and microionophoretic application of delta-sleep-inducing peptide. It was found that the number of neurons not responding to stimulation in the lateral hypothalamus surpassed the number of sensitive neurons (63 and 37%, respectively). Hippocampal neurons in active animals were less sensitive to stimulation of the lateral hypothalamus than in passive rats (33 vs. 42%) After application of delta-sleep-inducing peptide, only 28% neurons responded to stimulation. Thus, delta-sleep-inducing peptide reduced the sensitivity of hippocampal neurons to stimulation of the lateral hypothalamus.

Effect of delta sleep-inducing peptide on oxidative modification of proteins in rat tissues and blood during physiological aging.

Accumulation of oxidized proteins (evaluated by the levels of carbonyl and SH groups) in tissues of 2-24-month-old rats (spleen>myocardium>testicles>liver>skeletal muscles) has been demonstrated. Exogenous delta sleep-inducing peptide injected subcutaneously to rats of different age in a dose of 100 µg/kg by monthly 5-day courses protected proteins of the studied tissues from oxidation; its effect was tissue-specific. Delta sleep-inducing peptide exhibited a hypoglycemic effect: it prevented nonenzymatic glycosylation of hemoglobin and reduced the level of defective protein molecules during aging.

[Effect of delta-sleep inducing peptide on the functional activity of some organs and tissues of rats during physiological aging].

The authors show that exogenous delta-sleep inducing peptide (DSIP) injected subcutaneously to the rats in the age of 2-24 months of postnatal development in a dose of 100 mg/kg of animal body weight in courses for 5 consecutive days every month, has a hepatoprotective effect. DSIP does not affect the functional activity of the pancreas, and is not involved in the regulation of calcium homeostasis in the physiological aging of the organism.

[Mechanism of delta-sleep inducing peptide geroprotective activity].

It is shown that the subcutaneous injection to the rats in the age from 2 to 24 months during 5 consecutive days every month with 10 microg/100 g body weight of delta-sleep inducing peptide (DSIP) suppresses lipid peroxidation preventing the increasing of malonic dialdehyde level in rats tissues and plasma, possesses a powerful antioxidant effect, which is realized by means of the activation of different endogenous antioxidant defense system of cell and extracellular fluid, including high- and low-molecular regulators of free radical processes. DSIP exerts stimulating influence upon the superoxid-dismutese, catalase, ceruloplasmin activities as well as the level of nonenzymatic antioxidants--urea and uric acids, because during organism aging the antioxidant defense systems are being suppressed. DSIP increases the volume of tissues and blood endogenous antioxidant defense system mainly by means of enzymatic antioxidant system, especially during later ontogenesis.

[Changes in duodenal lymphoid structures in rats with various behavioral activity, caused by delta sleep-inducing peptide and following acute emotional stress].

The effect of delta sleep-inducing peptide (DSIP) on the lymphoid structures of small intestine, was investigated. Studies were conducted on 42 male Wistar rats, which were previously assessed in an "open field" test. According to the results of the test, rats were divided into behaviorally active animals (prognostically resistant to stress) and passive ones (resistant to the effects of stress). As a stress, immobilization of the animals in pens with an electrical stimulation of their back for 1 hour, was used. Intraperitoneal injection of DSIP resulted in a reduction of eosinophil number in rats of all the experimental groups. After DSIP injection to the active rats of the control group, the increase in small and medium lymphocyte numbers was detected that was more expressed than in the passive rats. After an acute exposure of behaviorally active rats to stress, the number of the cells of lymphoid series was increased,mainly due to the increase in small and medium lymphocytes. In the group of passive rats, stress exposure and DSIP injection resulted in the increase of plasma cell number in all the duodenal mucosa structures studied.

Effect of delta-sleep-inducing peptide on expression of heat shock protein 70 kDa in K562 cells.

For evaluation of the stress-protective influence of delta-sleep inducing peptide we studied its effects on the system of heat-shock proteins in immune cells using the method of flow cytometry. The peptide affected the expression of heat-shock protein 70 kDa in cultured human myeloleukemia K562 cells. Delta-sleep-inducing peptide reduces accumulation of intracellular heat shock proteins 70 kDa in cells cultured under conditions of high density.

Delta sleep-inducing peptide alters bispectral index, the electroencephalogram and heart rate variability when used as an adjunct to isoflurane anaesthesia.

BACKGROUND AND OBJECTIVE: Delta sleep-inducing peptide (DSIP) is an endogenous peptide that crosses the blood-brain barrier, named after its association with natural sleep and enhanced electroencephalogram (EEG) delta rhythm. The objective of this study was to determine whether DSIP could be used as an adjunct to volatile anaesthesia in humans, our hypothesis being that DSIP is a natural hypnotic that would increase anaesthetic depth. The aims were to assess depth of anaesthesia using bispectral index (BIS), the EEG and heart rate variability (HRV), and to determine whether DSIP altered the symmetry of EEG between the left and right cerebral hemispheres. METHODS: Twenty-four female ASA I or II patients gave written, informed consent to a protocol approved by our local research ethics committee. Twelve were randomly assigned as controls to receive saline. The other 12 were randomly allocated to receive one of three intravenous bolus doses of DSIP (Clinalfa) at 25, 50 or 100 nmol kg(-1). The first administration of DSIP was while awake and the second after induction of anaesthesia with propofol and maintenance with isoflurane. BIS and EEG parameters were measured continuously using a bilateral electrode montage. RESULTS: DSIP significantly increased heart rate, decreased HRV and, paradoxically, significantly reduced delta rhythm along with reducing burst suppression and increasing BIS at 25 nmol kg(-1) during isoflurane anaesthesia. DSIP also significantly altered bilateral symmetry of EEG. CONCLUSION: DSIP probably reduced parasympathetic tone and decreased (lightened) the depth of anaesthesia measured using BIS.

[Effect of delta-sleep inducing peptide preparation Deltaran on longevity, physiological functions, and carcinogenesis in mice].

Female SHR mice received 5-days long monthly courses of delta-sleep inducing peptide (DSIP) preparation "Deltaran" subcutaneously in dose 5 mkg/kg during all their lives. It was demonstrated, that last 10% (most aged) of mice which received Deltaran lived for 16% longer than the controls. They had significantly higher amount of vertical activity in the "open field" test, than the controls, starting from time when they were 6 months old and until their natural death. Mice of Deltaran group spent 73% more time in the open arms of elevated plus maze, and 9 times more often explored the extremities of this maze, than controls. Also Deltaran slowed the spontaneous carcinogenesis parameters. It's assumed that DSIP preparation "Deltaran" have geroprotective, anxiolytic and antitumor activity.

[Endogenous anticonvulsants: neuropeptide Y and delta sleep inducing peptide].

INTRODUCTION: The same neuropeptides regulate both cicle sleep-wake and excitability of the brain. CONCLUSION: Literature data together with our results support the idea that delta sleep--inducing peptide and neuropeptide Y could represent one of the factors of the endogenous stabilization of brain excitability and potent antiepileptic in generalized metaphit-induced audiogenic convulsive activity. The same holds true for DSIP analogues.

Delta sleep-inducing peptide and Deltaran: potential approaches to antistress protection.

The aims of the present work were to perform a comparative study of the effects of delta sleep-inducing peptide and Deltaran on neurons in emotiogenic brain structures and to address the question of whether it is possible to prevent or decrease the negative influences of stress loads on the severity of subsequent cerebral ischemia in rats, using glycine with delta sleep-inducing peptide combined in the neuroprotective formulation Deltaran. The results showed that Deltaran and delta sleep-inducing peptide had largely the same actions on the nature of spike activity of neurons in the dorsal hippocampus, paraventricular nucleus of the hypothalamus, and ventral anterior nuclei of the thalamus, evoking activation of some of the neurons in these brain structures. The dorsal hippocampus was dominated by activation of spike activity in response to administration of delta sleep-inducing peptide; Deltaran produced activation mainly in the paraventricular nuclei of the hypothalamus. In all animals given Deltaran, the index of brain blood supply was significantly greater than in animals not given Deltaran. The survival rate of cerebral ischemia was 100% in animals given Deltaran. Death occurred in 38% of animals not given Deltaran.

[Effect of delta-sleep inducing peptide on free-radical processes in the brain and liver of mice during various light regimens].

Female SHR mice received 5-days long course of delta-sleep inducing peptide preparation "Deltaran" subcutaneously in daily dose of 5 mkg/mice per 24h under standard light regime (12h light: 12 h darkness) or constant illumination. Free-radical level and antioxidative activity in brain and liver was studied by standard methods. Constant illumination increased chemiluminescence in brain by 20 % and decreased liver glutationperoxidase activity by 60 %, as compared to the mice kept in standard light regime. In conditions of standard light regime deltaran increased levels of general antioxidative activity in brain by 9%, liver superoxide dismutase by 17% and lowered levels of glutationperoxidase of liver by 82%. In conditions of constant illumination Deltaran lowered levels of chemiluminescence in liver by 23%, raised the general antioxidative activity in liver by 19% and lowered levels of glutationperoxidase of liver by 69%. It was supposed that deltaran has an antioxidant effect under constant light regime.