[Chronic sleep restriction in rats leads to a weakening of compensatory reactions in response to acute sleep deprivation]. / Khronicheskoe ogranichenie sna u krys privodit k oslableniyu kompensatornykh reaktsii v otvet na ostruyu deprivatsiyu sna.

OBJECTIVE: To identify features in the compensatory mechanisms of sleep regulation in response to acute sleep deprivation after chronic sleep restriction in rats. MATERIAL AND METHODS: Male Wistar rats 7-8 months old underwent 5-day sleep restriction: 3 h of sleep deprivation and 1 h of sleep opportunity repeating throughout each day. Six-hour acute total sleep deprivation was performed at the beginning of daylight hours on the 3rd day after sleep restriction. Polysomnogramms were recorded throughout the day before chronic sleep restriction, on the 2nd recovery day after chronic sleep restriction and after acute sleep deprivation. The control group was not subjected to chronic sleep restriction. RESULTS: The animals after chronic sleep restriction had the compensatory increase in total sleep time in response to acute sleep deprivation weaker than in control animals. Animals after sleep restriction had the compensatory increase in the time of slow-wave sleep (SWS) only in the first 6 hours after acute sleep deprivation, whereas in control animals the period of compensation of SWS lasted 12 hours. A compensatory increase in slow-wave activity (SWA) was observed in both groups of animals, but in animals experiencing chronic sleep restriction the amplitude of SWA after acute sleep deprivation was less than in control animals. A compensatory increase in REM sleep in sleep restricted animals occurred immediately after acute sleep deprivation and coincides with a compensatory increase in SWS and SWA, whereas in control conditions these processes are spaced in time. CONCLUSION: Compensatory reactions in response to acute sleep deprivation (sleep homeostasis) are weakened in animals subjected to chronic sleep restriction, as the reaction time and amplitude are reduced.

Preventive Administration of the Heat Shock Protein Hsp70 Relieves Endotoxemia-Induced Febrile Reaction in Pigeons ( Columba livia ) and Rats.

The stress-inducible 70 kDa heat shock protein (Hsp70) can exert a protective effect on endotoxemia and sepsis due to its ability to interact with immune cells and modulate the immune response. However, it remains unknown whether Hsp70 is able to relieve endotoxemia-induced fever. We carried out a comparative study of the effects of preventive administration of the human recombinant Hsp70 (HSPA1A) on lipopolysaccharide (LPS)-induced endotoxemia in pigeons and rats with preimplanted electrodes and thermistors for recording the thermoregulation parameters (brain temperature, peripheral vasomotor reaction, muscular contractile activity). Additionally, we analyzed the dynamics of the white blood cell (WBC) count in rats under the same conditions. It was found that preventive administration of Hsp70 relieves the LPS-induced febrile reaction in pigeons and rats and accelerates the restoration of the WBC count in rats. The data obtained suggest that these warm-blooded animals share a common physiological mechanism that underlies the protective effect of Hsp70.

[Modeling of chronic sleep restriction for translational studies]. / Sozdanie modeli khronicheskogo nedosypaniya dlya translyatsionnykh issledovanii.

OBJECTIVE: To develop of a chronic sleep restriction model in rats by repeated sleep deprivation using an orbital shaker and to determine whether this model leads to disturbances in sleep homeostatic mechanisms. MATERIAL AND METHODS: Male Wistar rats (7-8 months old) underwent sleep restriction for five consecutive days: 3 h of sleep deprivation and 1 h of sleep opportunity repeating throughout each day. Polysomnograms were recorded telemetrically throughout the day before sleep restriction (baseline), on the 1st, 3rd, 5th day of sleep restriction and 2 days after the end of sleep restriction (recovery period). RESULTS: During the period of sleep restriction, the total amount of slow-wave sleep (SWS) and rapid eye movement (REM) sleep decreased by 61% and 55%, respectively, compared to baseline. On the first day of recovery, amount of SWS increased mainly in the dark (active) phase of the day, while REM sleep increased in both light and dark phases; there was no marked rebound of daily SWS amount, while REM sleep increased by 30% from baseline. On the first day of recovery, an elevation of EEG beta and sigma power in sleep states was observed mainly in the light phase of the day. The loss of deep SWS throughout the sleep restriction period increased from 50% on 1st day to 75% on 5th day. The level of deep SWS remained below the baseline by 15-20% on the two subsequent days of recovery. The findings suggest that homeostatic mechanisms of SWS are persistently impaired after 5-day chronic sleep restriction. Besides, a decline of wakefulness accompanied by an increase of SWS in the active phase of the recovery period indicates a disruption in circadian rhythm. CONCLUSION: The proposed model leads to the disruption of sleep homeostatic mechanisms, which, in turn, impede compensation of SWS loss caused by chronic insufficient sleep.

[Age-related differences in sleep disturbances in rat models of preclinical Parkinson's disease]. / Vozrastnye osobennosti narushenii sna v modelyakh doklinicheskoi stadii bolezni Parkinsona u krys.

OBJECTIVE: To describe the changes in temporal characteristics of sleep-wake cycle, which can serve as non-motor manifestations of an early stage of Parkinson's disease (PD), using the model of preclinical PD in rats of two age groups. MATERIAL AND METHODS: A prolonged (up to 21 days) model of preclinical PD in middle-aged (7-8 month) and aged (19-20 month) rats was created. The model was based on cumulative inhibition of proteasomal system of the brain caused by intranasal administration of lactacystin, a specific proteasome inhibitor. Polysomnographic data were recorded daily using telemetric Dataquest A.R.T. System (DSI, USA) in unrestrained animals. RESULTS AND CONCLUSION: Aging was accompanied with increased sleepiness during the active (dark) phase of the day (as was implied by a two-fold increase in the total time of drowsiness) and with 1.5-fold growth of light sleep during the inactive phase of the day. A common feature of sleep disturbances in the model of preclinical PD in both middle-aged and aged rats was hypersomnia during the active phase of the day. It was suggested to be similar to the excessive daytime sleepiness in humans. Hypersomnolence was more pronounced in aged rats because it added to sleepiness developing with aging. In both age groups, the model of preclinical PD was also associated with a decrease in EEG delta power during slow-wave sleep. It is considered dangerous because it might represent the decrease in protein synthesis rate and the weakening of restorative processes in neurons, occurring with the prolonged inhibition of proteasomal system of the brain. Sleep disturbances, identified the model of preclinical PD in rats of different age, may be recommended for clinical validation as low-cost early signs indicating the initial stage of PD.

[U-133, a heat shock proteins inducer, precludes sleep disturbances in a model of the preclinical stage of Parkinson's disease in aged rats.]

Parkinson's disease (PD) is a chronic progressive neurodegenerative disease, closely associated with aging. It is considered incurable due to both late diagnosis and symptomatic treatment, which is able to alter neither molecular mechanisms of sleep disruption nor the neurodegenerative processes, developing with aging and PD progression. In the present study, we assess the therapeutic potential of a novel chaperone inducer U-133 (acetyl 2,3,7-tris-O-glucoside echinochrome) in the preclinical stage of PD modelled in aged rats by the inhibition of the proteasomal system in the brain. U-133 is a derivative of the sea urchin pigment echinochrome (2,3,5,7,8-pentahydroxy-1,4-naphthoquinone) produced by glycosylation, which possesses neuroprotective, antioxidant, anticancer properties. The administration of U-133, inducing the synthesis of Hsp70i and Hdj1 heat shock proteins in the brain, precludes the increase of light sleep (drowsiness) stage and the decrease of deep slow-wave sleep total time, both occurring with the progression of the preclinical stage of PD modelled in aged Wistar rats. Deep slow-wave sleep is thought to promote glymphatic clearance and to accelerate protein synthesis. Thus, U-133-induced increase in deep slow-wave sleep percentage, as compared to the preclinical model, is considered having a neuroprotective effect that contributes to the intensification of the restorative function of neurons and counteracts the progressing neurodegeneration.

[Signs of anhedonia and destructive changes in the ventral tegmental area of the midbrain in the model of the preclinical Parkinson's disease stage in experiment]. / Priznaki angedonii i destruktivnye izmeneniia v ventral'noi oblasti pokryshki srednego mozga v modeli doklinicheskoi stadii bolezni Parkinsona v éksperimente.

Parkinson's disease (PD) is one of incurable socially significant diseases. Success in the PD treatment is associated with the development of the technology of preclinical diagnosis and neuroprotective treatment of the disease. In the experimental model of the preclinical PD stage in rats created by intranasal administration of the proteasome inhibitor lactacystin, signs of depression as an anhedonia symptom were detected for the first time. Anhedonia was combined with the death of about one third of dopamine (DA)-ergic neurons in the ventral tegmental area of the midbrain and their axons in the ventral striatum; and a decrease of dopamine concentration in the ventral striatum (by 40%) and the tyrosine hydroxylase level in surviving DA-ergic neurons. The signs of depression may be an early marker of PD, signaling the onset of neurodegeneration in the mesolimbic brain system and increasing functional deficit of the DA-ergic transmission in the ventral striatum. The study results can be applied to the development of the technology of preclinical PD diagnosis and pathogenetic therapy.

[Study of age changes in compensatory processes on the model of neurodegeneration of nigrostriatal system in rats.]

It is generally accepted that advanced age is the main risk factor for the development and progression of Parkinson's disease (PD). However, data that experimentally confirm the dependence on the age of the rate of neurodegeneration progression and the activity of compensatory processes in the nigrostriatal system in the development of PD are absent in the modern literature. The present study uses a model of neurodegeneration of the nigrostriatal system in rats of different age groups, created by the microinjections of the proteasome inhibitor lactacystin (LC) into the substantia nigra pars compacta (SNpc). The model reproduces the main pathomorphological signs of PD with great reliability. It is shown for the first time that LC administration to old rats, in comparison with young and middle-aged, causes more pronounced neurodegenerative changes in the nigrostriatal system, associated with impairments of fine motor function, a decrease in the growth of the stress-inducible heat shock protein Hsp70 in surviving neurons of SNpc and a decrease in the tyrosine hydroxylase and the vesicular monoamine transporter 2 contents. The data obtained allow us to summarize that the ageing-related weakening of Hsp70 expression combined with a decrease in the efficiency of compensatory processes are significant factors that determine the progression of pathology in the nigrostriatal system in the modeling of PD in old rats. The demonstrated age-related loss of compensatory mechanisms may be one of the reasons for the rapid PD progression in the elderly.

[Changes in characteristics of sleep-wake cycle and motor activity at the preclinical stage of Parkinson's disease in old rats]. / Izmeneniia kharakteristik sna i summarnoi dvigatel'noi aktivnosti v modeli doklinicheskoi stadii bolezni Parkinsona u starykh krys.

AIM: To assess the changes in temporal characteristics and total motor activity (MA) during the sleep-wake cycle in old rats in the model of the preclinical stage of Parkinson's disease (PD). MATERIAL AND METHODS: Progressing inhibition of proteasome system and prolonged (up to the 21st day) development of the preclinical stage of PD in 19-20-month Wistar rats was caused by the specific proteasomal inhibitor lactacystin administered twice with a week interval. Telemetric monitoring of sleep-wake cycle was performed along with the video recording of MA. Dopamine level in the dorsal striatum was measured by high-performance liquid chromatography. RESULTS: During the 13-21st days, the preclinical stage of PD in old rats was characterized by the following features: 1) increased drowsiness in the active (dark) phase of day that can be compared with the excessive daytime sleepiness in patients with PD; 2) growth of delta-activity indicating presumably a compensatory increase in the deep slow-wave sleep (SWS) stage; 3) decreased MA during SWS and drowsiness, which was coupled with the lowered dopamine level in the dorsal striatum typical for the preclinical stage of PD. CONCLUSION: Both increased drowsiness and reduced MA during sleep, reflecting dopamine deficit in the nigrostriatal system, may be recommended for using in clinical research as inexpensive early markers of the preclinical stage of PD.

[Parkinson's disease and aging.]

Parkinson's disease (PD) is one of the most severe human neurodegenerative diseases that is mainly represented by sporadic form with multifactorial nature and commonly diagnosed in persons over 65 years of age. Current data on molecular mechanisms of PD development and their connection with processes of aging have been given in the review. Mechanisms of conformational control and selective degradation of proteins in the cell, possible trigger factors initiating the cascade of pathological reactions have been analyzed. Perspectives to solve the problem of elimination of basic causes of PD incurability (late diagnosis, and ineffective treatment) related to determination of reliable non-motor markers of the preclinical identification and early disorder correction of integrative brain functions have been evaluated. The basic attention is paid to an analysis of early sleep and behavior disorders in PD and aging. Known at the present moment endogenous neuroprotective factors capable to inhibit the neurodegenerative process in this disease have been considered.

Impairment of non-associative learning in a rat experimental model of preclinical stage of Parkinson's disease.

An experimental model of the preclinical stage of Parkinson's disease was induced by double intranasal administration of the proteasome inhibitor lactacystin. The results demonstrated signs of cognitive impairments expressed as impaired non-associative learning. This was related to degeneration of one-third of dopaminergic neurons in the ventral tegmental area of the midbrain and their axons in the dorsolateral prefrontal cortex. Impairment of non-associative learning may be an early non-motor marker of Parkinson's disease indicating the start of neurodegenerative processes in the dopaminergic mesocortical system of the brain.

[EFFECT OF QUERCETIN ON NEURODEGENERATIVE AND COMPENSATORY PROCESSES IN NIGROSTRIATAL SYSTEM IN A MODEL OF PRECLINICAL PARKINSON''S DISEASE STAGE IN RATS].

Data on HSP70 involvement in Parkinson's disease (PD) pathogenesis, received in last 10 years, cannot answer the question whether the decrease in stress-inducible Hsp70 brain expression is one of the reasons for progressive neurodegeneration in PD. In the present study, the inhibitor of HSPs expression quercetin was used in a rat model of nigrostriatal system proteasome dysfunction. This model was created by the microinjections of the specific proteasome activity inhibitor lactacystin, that was injected locally to the substantia nigra pars compacta (SNpc). The model reproduces the under-threshold level of nigrostriatal degeneration and neurochemical features characteristic of the preclinical PD stage. It was shown for the first time that quercetin pretreatment inhibited the LC-induced expression of Hsp70 in the SNpc neurons and increased in 1.5 times the dopamine (DA)-ergic neurons death and in 2.7 times the striatal DA-ergic axons degeneration. These changes were accompanied by the depletion of compensatory mechanisms and HSP70 content in the SNpc neurons and the appearance of the motor dysfunctions, typical for the clinical PD stage. The results of this investigation indicate the important role of Hsp70 in mechanisms of the nigrostriatal system protection in proteasome dysfunction, characteristic for the pre-clinical PD stage. The data obtained can be considered as the scientific basis for the development of new technologies for early PD therapy by exogenous Hsp70.

[Role of adenosine A(2A) receptors of preoptical area in realization of somnogenic effect of protein 70 kDa in pigeons].

In representatives of class of birds (pigeons Columba livia) using electrophysiological methods for the first time there was performed analysis of effects of microinjections into the hypothalamic ventrolateral preoptical area (VLPA) of antagonists of the adenosine A(2A) type receptors on the sleep-wale cycle under natural conditions and on realization of somnogenic effect of Heat shock protein 70 kDa (Hsp70). The following has been established: 1) microinjections of adenosine A(2A) receptors antagonist (8-(3-Chlorostyryl) caffeine (ChC)) into VLPA at the beginning of inactive phase of the 24-h period dose-dependently increase wakefulness and suppress sleep; 2) microinjections of Hsp70 into VLPA produce somnogenic effect manifested as an increase of the total time of slow sleep (SS) and enhancement of mechanisms of initiation and maintenance of SS; 3) block of adenosine A(2A) receptors by ChC suppresses the Hsp70-induced SS. The obtained data indicate participation of adenosine A(2A) receptors located in VLPA in modulation of the sleep-wake cycle under natural conditions and in realization of somnogenic effect of Hsp70 in pigeons. A hypothesis is put forward that the somnogenic action of Hsp70 is mediated by modulating effect of this chaperone on function of adenosine proteins-receptors.

[A study of participation of Hdj1 co-chaperone in the modulation of sleep and behavior using micro RNA technology in vivo].

Data obtained for the last 12 years and modern hypotheses on key function of sleep and the role of Heat Shock Protein 70 kDa (HSP70) molecular chaperones family in sleep modulation are insufficient to determine assotiation of sleep quantity to the level of chaperones in the basic "center" of sleep in the ventrolateral preoptic area (VLPA) of the hypothalamus. In the present study, to reduce the content of Hdj1 major co-chaperone of Hsp70 in the VLPA we employed a novel approach based on lentiviral construction containing specific Hdj1-shRNA. The immunoblotting data showed that in 6 weeks after infection the level of Hdj1 in VLPA was reduced by 80% that was accompanied by a considerable increase in the quantity of slow-wave sleep and a marked decrease in the level of anxiety; earlier we found that elevation of Hsp70 level in the rat brain resulted in similar changes. It is suggested that the increase in quantity of slow wave sleep and the decrease in the level of anxiety can be related to a sustained disorder in the integration between molecular systems based on chaperones Hdj1 and Hsp70 and to a compensatory increase in the Hsp70 chaperone activity/level in VLPA.

[Content of chaperon Hsp70 in dopaminergic neurons of the black substance increases in proteasome dysfunstion].

In Wistar rats, specific inhibitor UPS lactacystin induced degeneration of 24% of the dopaminergic neurons in the black substance. The work shows that a moderate weakening of the UPS function is characterized by an enhanced activity of the shaperon system. This process seems to restore and maintain population of the dopaminergic neurons.

[Thermophysiology of the paradoxical sleep].

Data on interactions between the paradoxical sleep (PS) and thermoregulation under thermo-comfortable and extreme conditions (in high and low temperatures, forced and spontaneous fasting, acclimation to cold and acclimation to natural winter conditions) are reviewed. The hypothesis of the PS role in synchronising and endogenous "kindling" of the visceral function ultradian rhythms is substantiated. Some new data are presented on entering torpor as a phenomenon of the "dramatic" neuronal plasticity.

[Study of the protective effects of exogenous heat shock protein 70 kDa in the model of sleep deprivation in pigeons Columba livia].

Electroencephalographic methods were used to study effects of the preparation of the exogenous heat shock protein with molecular mass 70 kDa (Hsp70i/Hsc70) on the time characteristics of sleep and waking, brain temperature, peripheral vasomotor reactions and thoracic muscle contractile activity after the 5-hour sleep deprivation in pigeons (Columba livia). The microinjections of Hsp70i/Hsc70 were performed into the third brain ventricle after the end of sleep deprivation. It was shown that Hsp70i/Hsc70 eliminated the disturbances of sleep-wake cycle and evoked a decrease in the thoracic muscle contractile and brain temperature during the first hour of postdeprivation period. During the following hours Hsp70i/Hsc70 evoked an increase in the total time of deep sleep and a decrease in the total time of rapid-eye-movement sleep. We suppose that the protective effects of Hsp70i/Hsc70 could be associated with its capacity to weaken the activity of the hypothalamo-hypophyseal-adrenal axis and to enhance the stress-limiting function of non-rapid-eye-movement sleep.