Features of regulating delta sleep-inducing peptide by free radical processes in tissue and erythrocyte membranes in intact animals and under stress

In activity the comparative analysis of metabolic effects delta--sleep inducing peptide (DSIP) in tissues and erythrocytes of intact rats and under cold stress is conducted. The regulation effect of DSIP in attitude of free radical processes will be realised through modulation the prooxidant--antioxidant balance: both for intact animal, and at stress. Exogenous DSIP increases the antioxidant system activity in tissues of brain, liver and blood in standard conditions and under cold stress. The anti-stress effect of DSIP is directed as on increase of power endogenic enzymatic antioxidant system activity, specially glutathione peroxidase activity, and not enzymatic of antioxidant protection. The DSIP renders different influence on activity of prooxidant enzymes: for intact animal boosts the myeloperoxidase activity in blood neutrophils, not rendering essential influencing on the xanthine oxidase activity in tissues of brain, liver and activates the myeloperoxidase activity, depresses the xanthine oxidase activity for rats at stress. The membranotropic effect of DSIP in the norm and under stress is connected to increase of stability of protein--lipid interplays. The membranostabilizing effect of DSIP in conditions of stress is characterized decrease of polarity of lipid phase and negative surface charge of erythrocyte membranes, modified in course of lipid peroxidation.     

Effects of delta-sleep-inducing peptide during ischemic injury of the rat brain

An anti-ischemic effect of the delta-sleep-inducing peptide (DSIP) was found in rats. The DSIP effect was more obvious than that of the MK-801. The data obtained is discussed considering a possible use of the DSIP for brain stroke prophylaxis.     

The Delta-Sleep Inducing Peptide in Cerebral Mechanisms of Emotional Stress

The problem of the anti-stressor effect of the delta-sleep inducing peptide (DSIP) and of its neurophysiological mechanisms of action is considered. Physiological data are exposed that indicate an intraventricular administration of DSIP in rats to results in an increase of resistance to emotional stress, according to behavioral and autonomous reactions, and in a decrease of excitability of the brain structures responsible for protective reaction. Radioimmunological evidence is presented for the resistance of animals to emotional stress to depend on the content in hypothalamus of certain oligopeptides, such as -endorphin, DSIP, and the substance P. It was shown that animals resistant to emotional stress had a higher content of these oligopeptides in hypothalamus than those predisposed to stress. The issue is discussed that the prolonged anti-stressor effects after the DSIP administration are determined by considerable changes of the content of other polypeptides and hormones in hypothalamus and blood, which are involved in the reaction under the effect of DSIP.     

The frequency composition of the brain electrical activity in rats after the use of the delta-sleep peptide and its analogs]

Frequency spectra of brain electrograms in the course of 1 h after peripheral and central administration of the delta-sleep peptide (DSIP) or two its analogues were studied in freely moving rats. In autumn series of experiments carried out on 18 animals was revealed the phase action of DSIP being manifested in initial (up to 20 min after the injection) suppression of fast (20-26 Hz) oscillations in electrocorticograms and their augmentation in subsequent intervals. Under the identical conditions analogues of DSIP induced the effects characteristic for different phases of DSIP action. In spring-summer series of experiments carried out in 6 animals was revealed a significant increase of the delta-waves in electrical activity of the Putamen after intraperitoneal injection of DSIP and its first analogue. Under the conditions of intraventricular injection DSIP induced stable augmentation of oscillations in a diapason of 14-16 Hz in the neocortex, and its analogues induced similar changes in a nearby frequency diapason of 9.6-11 Hz.     

The effect of the delta-sleep peptide on the adrenaline level in rat tissues under normal conditions and during cold stress

Adrenalin content in the brain, liver and adrenal glands under the effect of cold stress grows by 314, 500 and 56% as compared to the control. A single administration of the delta-sleep inducing peptide (DSIP) in a dose of 12 microgram/100 g to intact animals makes the adrenalin content in the brain higher 1, 3, 6 and 24h after administration; two and three days later the adrenalin content in the brain does not change. The amount of adrenalin in the liver of the same animals increases 1, 3, 6 h and 1, 2, 3 days after DSIP administration. Intraperitoneal administration of DSIP induces an increase of the adrenalin level in the adrenal glands of rats an hour and a day after administration. Two days later the level of adrenaline decreases by 41%; 3, 6 h and 3 days after DSIP administration the content of adrenaline remains unchanged. As a result of the DSIP administration in a dose of 12 micrograms/100 g to the animals in the state of cold stress, the content of adrenalin increases in the rat brain by 129, in the liver--by 300, adrenal glands--by 44% as compared with the control.     

Enhanced electron transfer of different mediators for strictly opposite shifting of metabolism in Clostridium pasteurianum grown on glycerol in a new electrochemical bioreactor

Microbial electrosynthesis or electro-fermentation in bioelectrochemical systems (BES) have recently received much attention. Here, we demonstrate with the glycerol metabolism by Clostridium pasteurianum that H ₂ from in situ water electrolysis, especially in combination with a redox mediator, provides a simple and flexible way for shifting product selectivity and enhancing product yield in the fermentation process. In particular, we report and quantify for the first time strictly different effects of Neutral Red (NR) and the barely studied redox mediator Brilliant Blue (BB) on the growth and product formation of C. pasteurianum grown on glycerol in a newly developed BES. We were able to switch the product formation pattern of C. pasteurianum with a concentration-dependent addition of NR and BB under varied iron availability. Interestingly, NR and BB influenced the glycerol metabolism in a strictly opposite manner concerning the formation of the major products 1,3-propanediol (1,3-PDO) and n-butanol (BuOH). Whereas, NR and iron generally enhance the formation of BuOH, BB favors the formation of 1,3-PDO. In BES the metabolic shifts were enhanced, leading to a further increased yield by as high as 33% for BuOH in NR fermentations and 21% for 1,3-PDO in BB fermentations compared with the respective controls. For the first time, the electron transfer mediated by these mediators and their recycle (recharge) were unambiguously quantified by excluding the overlapping effect of iron. BB has a higher capacity than NR and iron. The extra electron transfer by BB can account for as high as 30–75% of the total NAD ⁺ regeneration under certain conditions, contributing significantly to the product formation.     

Boosting mediated electron transfer in bioelectrochemical systems with tailored defined microbial cocultures

Bioelectrochemical systems (BES) hold great promise for sustainable energy generation via a microbial catalyst from organic matter, for example, from wastewater. To improve current generation in BES, understanding the underlying microbiology of the electrode community is essential. Electron mediator producing microorganism like Pseudomonas aeruginosa play an essential role in efficient electricity generation in BES. These microbes enable even nonelectroactive microorganism like Enterobacter aerogenes to contribute to current production. Together they form a synergistic coculture, where both contribute to community welfare. To use microbial co‐operation in BES, the physical and chemical environments provided in the natural habitats of the coculture play a crucial role. Here, we show that synergistic effects in defined cocultures of P. aeruginosa and E. aerogenes can be strongly enhanced toward high current production by adapting process parameters, like pH, temperature, oxygen demand, and substrate requirements. Especially, oxygen was identified as a major factor influencing coculture behavior and optimization of its supply could enhance electric current production over 400%. Furthermore, operating the coculture in fed‐batch mode enabled us to obtain very high current densities and to harvest electrical energy for 1 month. In this optimized condition, the coulombic efficiency of the process was boosted to 20%, which is outstanding for mediator‐based electron transfer. This study lays the foundation for a rationally designed utilization of cocultures in BES for bioenergy generation from specific wastewaters or for bioprocess sensing and for benefiting from their synergistic effects under controlled bioprocess condition.     

Effect of leu-enkephalin and the delta-sleep-inducing peptide, M (DSIP), on endogenous noradrenaline release by brain synaptosomes in the rat

Fluorometry was employed to measure the noradrenaline (NA) content in rat brain synaptosomes depending on the duration of incubation, depolarization effects (40 mM KCl or 1.5 mM ouabain), composition of the synaptosomal fraction and concentration of the peptides. The 10-minute incubation in a potassium medium of a suspension of light synaptosomes was used as an optimal test-system for studying the peptide action. Leu-enkephalin inhibited the depolarization-induced NA release. The effect was abolished by naloxone. The delta-sleep-inducing peptide (DSIP) did not influence the neurotransmitter release at concentrations of 10(-8)-10(-5) M. A mixture of amino acids imitating the amino acid composition of the DSIP influenced spontaneous release of NA. This effect is discussed in connection with the physiological action of the peptide on its intraventricular injection.     

Saturable mechanism for delta sleep-inducing peptide (DSIP) at the blood-brain barrier of the vascularly perfused guinea pig brain

Cellular uptake of [125I] labelled DSIP at the luminal interface of the blood-brain barrier (BBB) was studied in the ipsilateral perfused in situ guinea pig forebrain. Regional unidirectional transfer constants (Kin) calculated from the multiple-time brain uptake analysis were 0.93, 1.33 and 1.66 microliter.min-1 g-1 for the parietal cortex, caudate nucleus and hippocampus, respectively. In the presence of 7 microM unlabelled DSIP the brain uptake of [125I]-DSIP (0.3 nM) was inhibited, the values of Kin being reduced to 0.23-0.38 microliter.min-1 g-1, values that were comparable with the Kin for mannitol. The rapidly equilibrating space of brain, measured from the intercept of the line describing brain uptake versus time on the brain uptake ordinate, Vi, was greater for [125I]-DSIP than for mannitol; in the presence of unlabelled DSIP this was reduced to that of mannitol, and it was suggested that the larger volume for [125I]-DSIP represented binding at specific sites on the brain capillary membrane. L-tryptophan, the N-terminal residue of DSIP, in concentrations of 7 microM and 1 mM, inhibited Kin without affecting Vi. A moderate inhibition of Kin was obtained by vasopressin ([Arg8]-VP), but only at a concentration as high as 0.2 mM. The results suggest the presence of a high affinity saturable mechanism for transport of DSIP across the blood-brain barrier, with subsequent uptake at brain sites that are highly sensitive to L-tryptophan, and may be modulated by [Arg8]-VP.     

Antistressor effect of delta-sleep-inducing peptide in hypokinetic stress]

The influence of DSIP injection on the levels of neurotransmitters during hypokinetic stress was studied. It was shown that hypokinesia produced considerable changes in the levels of GABA glutamate, aspartate and homocarnosine. The injection of DSIP normalized the level of neurotransmitter amino acids. Administration of DSIP also reduced stress-induced changes in the activity of enzymes of GABA metabolism. Stress protective effect of DSIP was also demonstrated by normalising of the POL of lipids in brain.     

Delta sleep-inducing peptide (DSIP)-like material is absorbed by the gastrointestinal tract of the neonatal rat

Entry of delta sleep-inducing peptide (DSIP) into the circulation from the gastrointestinal (GI) tract was studied in unweaned rat pups. The pups were fed an analog of DSIP (N-Tyr-DSIP) or 125I-N-Tyr-DSIP and blood samples collected. Significant increases in plasma DSIP-like immunoreactivity occurred after the feeding of 100 ωg/animal of N-Tyr-DSIP but not after vehicle (normal saline) or 1 ωg/animal. Column chromatography showed this immunoreactivity to coelute with intact DSIP and des-Trp¹- DSIP. A small but statistically significant increase of immunoreactivity occurred in the plasma of pups whose nursing mothers were injected with N-Tyr-DSIP but not in those whose mothers were injected with saline. Radioactivity appeared in both the brain and blood of 1–2 and 10 day old rat pups fed 125I-N-Tyr-DSIP. Although only a small amount of the radioactivity in plasma co-eluted with intact 1251I-N-Tyr-DSIP on column chromatography, almost all of the radioactivity in brain did, suggesting that the radioactivity in the brain represented crossing of the blood-brain-barrier by the peptide and not just contamination by blood. The results cannot be explained by either regurgitation of intestinal contents, or by stimulation of endogenous peptide. They show that a DSIP peptide administered orally can be absorbed through the GI tract into the systemic circulation.     

Amphetamine-induced locomotor behavior of mice is influenced by DSIP

The delta sleep-inducing peptide (DSIP) has been shown to induce effects other than only delta sleep. One of these effects was the paradoxical thermoregulatory and locomotor response of rats to amphetamine after DSIP administration. In the present investigation we found similar effects of DSIP on the locomotor activity in mice. However, two different doses of DSIP (30 and 120 nmol/kg) and 3 doses of amphetamine (4, 10, and 15 mg/kg) produced a complex pattern of effects in mice tested at 22 degrees C. In general, DSIP-treated mice showed lower locomotor activity after amphetamine than controls, but under two conditions, both using 15 mg/kg amphetamine, DSIP produced higher scores; this occurred in the first two hours after amphetamine for the 30 nmol/kg DSIP group and in the third hour for mice given 120 nmol/kg DSIP. The results indicate that the effects of DSIP on locomotor behavior were dependent on the dosage of the peptide and the time of measurement as well as the level of amphetamine stimulation.     

Delta-sleep inducing peptide (DSIP) and its fragments as the modulators of neural transmission in the central nervous system

The present study is a continuation of our previous experiments on DSIP activity which have revealed that nonapeptide DSIP inhibits hippocampal electrical activity of the 4-7 c/s frequency band. The aim of the present study was to find which of the known DSIP fragments is responsible for its activity, i.e. to find the active site of the molecule. The experiments were carried out with the entire DSIP molecule and its three different fragments. The method of threshold continuous arousal pattern (TCAP) monitoring was used as the indicator of DSIP activity. It was found that the entire DSIP molecule increased TCAP, while its 1-5 fragment decreased it 1-4 and 5-9 fragments had no noticeable effect.     

Oligopeptides in the development of biological motivations

Data are presented, demonstrating the action of a number of oligopeptides on biological motivations of hunger, fear, self-stimulation and on alcohol addiction. In the structure of animals feeding motivation, such oligopeptides take part as beta-lipotropin and its fragments, ACTH, pentagastrin, delta-sleep inducing peptide (DSIP), substance P; in organization of defensive motivation--angiotensin II (AII), DSIP, substance P, bradykinin, beta-endorphin etc.; in organization of self-stimulation--AII, DSIP, bradykinin, ACTH, beta-endorphin etc. It is established that most of the above oligopeptides, injected to the brain lateral ventriculi, inhibit biological motivations, and only some of them have an activating action. On the basis of experiments, a hypothesis is formulated that oligopeptides act as a feedback between the genome of brain neurones and pacemaker cells of motivation centres of the hypothalamus area. Some oligopeptides elaborated by neuronal genomes under the action of dominating motivation, activate--and the other--suppress the activity of motivation hypothalamus centres.     

Distribution of the delta sleep-inducing peptide in the brain of rabbits: study by immunofluorescence

Using the indirect immunofluorescence method, the distribution of the Delta Sleep Inducing Peptide (DSIP)-containing neurons was studied in the rabbit brain. DSIP antisera were raised in rat by multiple injections of synthetic DSIP conjugated to thyroglobulin. Some DSIP immunoreactive cell bodies were detected in the diagonal band of Broca and anterior part of the hypothalamus. Large populations of immunofluorescent fibers and terminals were visualized mainly through the organum vasculosum of the lamina terminalis, the preoptic areas, the subfornical organ, the thalamus, the ventromedial hypothalamus and infundibulum. Further, most of the cells of the intermediate lobe of the hypophysis displayed DSIP-immunoreactivity. The predominant localization of DSIP-immunoreactive fibers and terminals in certain circumventricular organs suggests that DSIP could play a specific role in the neurohumoral regulation.     

Modification of the hypothermic circadian cycles induced by DSIP and melatonin in pinealectomized and hypophysectomized rats

Both melatonin and DSIP (a nine amino acid peptide) effects have been previously shown to be (a) circadian rhythm related and (b) involved in inducing hypothermic effects in rats. In this study we report the hypothermia effects by each of these drugs alone and in combination when studied in normal (unoperated), pinealectomized, and hypophysectomized rats at various time points of the corresponding circadian cycle. A clear differential effect of drugs × time × preparation was found. While both DSIP and melatonin hypothermic effects were both circadian cycle dependent in intact rats the rhythmicity of melatonin hypothermic effect in pinealectomized rats, and DSIP hypothermic effect in hypophysectomized rats was missing. Although several hypotheses have been offered to account for the physiological mechanism(s) that govern the effects of the drugs, it is not yet possible to reliably relate the findings to existing neurochemical theory.     

Delta sleep inducing peptide (DSIP): effect on respiration activity in rat brain mitochondria and stress protective potency under experimental hypoxia

Neuromodulatory delta sleep inducing peptide (DSIP) seems to be implicated in the attenuation of stress-induced pathological metabolic disturbances in various animal species and human beings. Mitochondria, as cell organelles, are considered especially sensitive to stress conditions. In this work, the influence of DSIP and Deltaran((R))-a recently developed product based upon DSIP-on processes of oxidative phosphorylation and ATP production in rat brain mitochondria and rat brain homogenates was studied. A polarographic measurement of oxygen consumption was applied to evaluate the impact of DSIP on maximal rates of mitochondrial respiration and coupling of respiration to ATP production. We provide evidence that DSIP affected the efficiency of oxidative phosphorylation on isolated rat brain mitochondria. This peptide significantly increased the rate of phosphorylated respiration V3, while the rate of uncoupled respiration V(DNP) remaining unchanged. It enhanced the respiratory control ratio RCR and the rate of ADP phosphorylation. DSIP and Deltaran exhibited the same action in rat brain homogenates. We also examined the influence of DSIP under hypoxia when mitochondrial respiratory activity is altered. In rats subjected to hypoxia, we detected a significant stress-mediated reduction of V3 and ADP/t values. Pretreatment of rats with DSIP at the dose of 120 microgram/kg (i.p.) prior to their subjection to hypoxia completely inhibited hypoxia-induced reduction of mitochondrial respiratory activity. The revealed capacity of DSIP to enhance the efficiency of oxidative phosphorylation found in vitro experiments could contribute to understanding pronounced stress protective and antioxidant action of this peptide in vivo.     

Action of the "delta-sleep peptide" on monoamine oxidase and acetylcholinesterase activity in subcellular fractions from different rabbit brain formations in vivo

Administration of delta-sleep-inducing peptide (DSIP) in vivo in a dose of 30 microgram/kg bw brings about MAO-A (substrate-serotonin) activation in synaptosome subfractions and cellular mitochondria from the brain structures (motor cortex, nucleus caudatus, thalamus). Activity of MAO-B (substrate-p-nitrophenylethylamine) and acetylcholinesterase was inhibited negligibly and specifically in subcellular fractions of the test brain structures. The results suggest that DSIP effects the regulatory or modulation function in the synapse. As one of the elements of sleep mechanisms this peptide induces a number of processes, particularly in serotonin metabolism.     

Effect of delta sleep-inducing peptide, anticonvulsant preparations and nicotinamide on generalized seizure activity

The influence of delta-sleep inducing peptide (DSIP) upon seizures induced by corazol, bicuculline, picrotoxin, strychnine, thiosemicarbazide were investigated in experiments on F1(CBA X C57 BL/6) mice. It was shown that DSIP increased the latency of first seizure manifestation which were induced by corazol, bicuculline and picrotoxin and also resulted in a suppression of seizure severity of corazol and bicuculline induced seizures. Anticonvulsant action of DSIP was evident under the condition of the mild severity seizures development. The effect of DSIP was mostly pronounced in range of its doses from 10 to 100 mcg/kg. DSIP when combined with phenobarbital, carbamazepine, diphenylhydantoin or nicotinamide enhanced the antiepileptic effects of these anticonvulsant drugs.     

Metabolic features of the adaptive effect of delta-sleep inducing peptide and piracetam under hyperoxic conditions.

Adaptive effects of delta-sleep inducing peptide (DSIP, 12 microgram/100 g body weight, single intraperitoneal injection) and piracetam (3 mg/100 g body weight, daily intraperitoneal injection for 3 days) are manifested via differential changes in neurotransmitter amino acids (GABA, glutamate, aspartate), modulation of transport ATPase activity, and decreased accumulation of lipid peroxidation products (conjugated dienes, malonic dialdehyde, Schiff bases) in various fractions of neuronal membranes (myelin, synaptic and mitochondrial membranes) in the sensomotor cortex of rat brain. Under hyperbaric oxygenation (0.3 MPa for 2 h), the combination of DSIP and piracetam enhanced the protective effect of each compound.