Delta-sleep inducing peptide and neuronal activity after glutamate microiontophoresis: the role of NMDA-receptors

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.

JmjC-domain-containing histone demethylases of the JMJD1B type as putative precursors of endogenous DSIP

Delta sleep inducing peptide (WAGGDASGE, DSIP) is a well known multifunctional regulatory peptide. Numerous studies have confirmed its stress-protective and adaptive activity which is independent of the origin or nature of the stress or other harmful factors. However, the biosynthetic origin of DSIP remains obscure, since nothing is known of its protein precursor(s) and their encoding gene(s). We have performed a comprehensive analysis of available gene and protein databases for homologous peptide sites within mammalian resources including man. A family of Jumonji C (JmjC)-domain-containing histone demethylases was shown to contain a sequence fragment closely homologous to DSIP. One type of these ubiquitous and phylogenetically ancient proteins encoded by JMJD1B gene includes the WKGGNASGE sequence that differs from DSIP by only 2 amino acid residues in positions 2 and 5. The respective peptide was synthesized and its biological effects were evaluated in a preliminary way in the forced swimming and antitoxic tests. We suggest that the histone demethylases of the JmjC-group containing DSIP-related region can be considered as possible protein precursors of endogenous peptides with DSIP-like 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 its analogues alleviate the severity of metaphit-induced audiogenic seizures in rats]

INTRODUCTION

We investigated the potential of delta sleep-inducing peptide (DSIP) and its analogue DSIP-12 (a nonapeptide with alanine in position 2 of DISP molecule substituted by beta-alanine) and tetrapeptide analogue DSIP1-4, to antagonize metaphit(1-1 (3-isothiocyanatophenl)-cvyclohexyl piperidine) induced generalized reflex audiogenic seizures in adult male Wistar albino rats.

MATERIAL AND METHODS

Five groups of adult male Wistar rats were intraperitoneally treated with: (1) saline; (2) metaphit: (3) metaphit + DSIP, (4) metaphit + DSIPI-4 and (5) metaphit + DSIP-12. To examine the blocking effects of DSIP and its analogues on fully developed metaphit seizures, in the last three groups they were administered 8h after metaphit injection. The rats were stimulated using an electric bell (1003 dB, 5-8 kHz, 60 s) one hour after metaphit injection and afterwards at hourly intervals during the experiment. For EEG recordings and power spectra three gold-plated screws were implanted into the skull.

RESULTS

In metaphit-treated animals EEGs appeared as polyspikes and spike-wave complexes, while power spectra were increasing. The incidence and severity of netaphit-induced audiogenic seizures reached a peak value at 7-12 h after injection. Both DSIP and DSIP analogues significantly increased power spectra of delta waves and decreased the incidence of seizures, as well as mean seizure grade and tonic component of metaphit-induced convulsions.

CONCLUSION

Taken together, these results suggest that DSIP and its analogues should be considered as potential antiepileptic agents.

Delta-Sleep-Inducing Peptide Potentiates Anticonvulsive Activity of Valproate against Metaphit-Provoked Audiogenic Seizure in Rats

The effect of delta-sleep-inducing peptide (DSIP) on the anticonvulsive activity of a nonprotective valproate (VPA) dose in a metaphit model of generalized, reflex audiogenic seizures in adult Wistar rats was studied. The animals that received metaphit (10 mg/kg) were exposed to audiogenic stimulation (100 +/- 3 dB, 60 s) at hourly intervals. Metaphit-treated rats displaying seizures in 8 previous tests were i.p. injected with VPA (50 mg/kg) or DSIP (1.0 mg/kg) or their combination. Latency to seizure was behaviorally assessed. The EEGs and power spectra were recorded and analyzed. Neurotoxicity was evaluated by the chimney test. DSIP or VPA alone expressed no significant effect on the latency duration, but their combination significantly prolonged latency to seizure during 6 h after injection, while inducing no significant motor impairment. Neither the applied drugs nor their combination abolished metaphit-provoked EEG epileptiform activity. The results show that DSIP potentiated anticonvulsive effects of a nonprotective VPA dose in a metaphit model of audiogenic seizures without influencing its neurotoxicity.