H2S prevents the disruption of the blood-brain barrier in rats with prenatal hyperhomocysteinemia.

Elevation of the homocysteine concentration in the plasma called hyperhomocysteinemia (hHCY) during pregnancy causes a number of pre- and postnatal developmental disorders. The aim of our study was to analyze the effects of H2S donors -NaHS and N-acetylcysteine (NAC) on blood-brain barrier (BBB) permeability in rats with prenatal hHCY. In rats with mild hHCY BBB permeability assessed by Evans Blue extravasation in brain increased markedly throughout life. Administration of NaHS or NAC during pregnancy attenuated hHCY-associated damage and increased endogenous concentrations of sulfides in brain tissues. Acute application of dl-homocysteine thiolactone induced BBB leakage, which was prevented by the NMDA receptor antagonist MK-801 or H2S donors. Rats with hHCY demonstrated high levels of NO metabolite - nitrites and proinflammatory cytokines (IL-1ß, TNF-α, IL-6) in brain. Lactate dehydrogenase (LDH) activity in the serum was higher in rats with hHCY. Mitochondrial complex-I activity was lower in brain of hHCY rats. NaHS treatment during pregnancy restored levels of proinflammatory cytokines, nitrites and activity of the respiratory chain complex in brain as well as the LDH activity in serum. Our data suggest that H2S has neuroprotective effects against prenatal hHCY-associated BBB disturbance providing a potential strategy for the prevention of developmental impairments in newborns.

[Sleep and cognitive impairment in neurodegenerative diseases]. / Son i kognitivnye narusheniia pri neirodegenerativnykh zabolevaniiakh.

Sleep and wakefulness disorders are commonly seen in patients with Parkinson's disease, Lewy body dementia and Alzheimer's disease. Sleep provides a lot of functions which sustain normal condition of the brain and sleep disturbances can be one of the factors contributing to the development of neurodegenerative diseases. Sleep and wakefulness disorders can worsen the course of the neurodegenerative process and lead to an increase of symptoms, including cognitive dysfunction. In this review, the relationship between sleep and wakefulness disorders and cognitive impairment as well as clinical forms of sleep and wakefulness disorders and treatment methods in such patients are discussed.

Hydrogen Sulfide Ameliorates Developmental Impairments of Rat Offspring with Prenatal Hyperhomocysteinemia.

Maternal high levels of the redox active amino acid homocysteine-called hyperhomocysteinemia (hHCY)-can affect the health state of the progeny. The effects of hydrogen sulfide (H2S) treatment on rats with maternal hHCY remain unknown. In the present study, we characterized the physical development, reflex ontogeny, locomotion and exploratory activity, muscle strength, motor coordination, and brain redox state of pups with maternal hHCY and tested potential beneficial action of the H2S donor-sodium hydrosulfide (NaHS)-on these parameters. Our results indicate a significant decrease in litter size and body weight of pups from dams fed with methionine-rich diet. In hHCY pups, a delay in the formation of sensory-motor reflexes was observed. Locomotor activity tested in the open field by head rearings, crossed squares, and rearings of hHCY pups at all studied ages (P8, P16, and P26) was diminished. Exploratory activity was decreased, and emotionality was higher in rats with hHCY. Prenatal hHCY resulted in reduced muscle strength and motor coordination assessed by the paw grip endurance test and rotarod test. Remarkably, administration of NaHS to pregnant rats with hHCY prevented the observed deleterious effects of high homocysteine on fetus development. In rats with prenatal hHCY, the endogenous generation of H2S brain tissues was lower compared to control and NaHS administration restored the H2S level to control values. Moreover, using redox signaling assays, we found an increased level of malondialdehyde (MDA), the end product of lipid peroxidation, and decreased activity of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the brain tissues of rats of the hHCY group. Notably, NaHS treatment restored the level of MDA and the activity of SOD and GPx. Our data suggest that H2S has neuroprotective/antioxidant effects against homocysteine-induced neurotoxicity providing a potential strategy for the prevention of developmental impairments in newborns.

[Dysfunction of the orexin system in Parkinson's disease]. / Narushenie funktsii oreksinergicheskoi sistemy pri bolezni Parkinsona.

Traditionally, Parkinson's disease (PD) is associated with the lesion of the substantia nigra and dopamine system dysfunction. However, current studies show the involvement of other CNS regions, which extend far beyond the substantia nigra, in the pathogenesis of PD. The prevalence of altered α-synuclein in PD leads to the dysfunction of several neurotransmitter systems including the orexin system located in the hypothalamus. The involvement of this system in the neurodegenerative process explains some symptoms of PD including daily drowsiness and eating disorders. The authors consider the pathophysiology of the orexin system and its role in the pathogenesis of PD.

Simulation of chlorophyll fluorescence rise and decay kinetics, and P700-related absorbance changes by using a rule-based kinetic Monte-Carlo method.

A model of primary photosynthetic reactions in the thylakoid membrane was developed and its validity was tested by simulating three types of experimental kinetic curves: (1) the light-induced chlorophyll a fluorescence rise (OJIP transients) reflecting the stepwise transition of the photosynthetic electron transport chain from the oxidized to the fully reduced state; (2) the dark relaxation of the flash-induced fluorescence yield attributed to the QA- oxidation kinetics in PSII; and (3) the light-induced absorbance changes near 820 or 705 nm assigned to the redox transitions of P700 in PSI. A model was implemented by using a rule-based kinetic Monte-Carlo method and verified by simulating experimental curves under different treatments including photosynthetic inhibitors, heat stress, anaerobic conditions, and very high light intensity.

[Sleep and wakefulness disorders in neurodegenerative diseases]. / Narusheniia sna i bodrstvovaniia pri neirodegenerativnykh zabolevaniiakh.

The article reviews the phenomenology of sleep and wakefulness disorders in Parkinson's disease and Alzheimer's disease. Degeneration of sleep and wakefulness centers, secondary effect of other symptoms of diseases and side-effects of drug therapy lead to a widespread prevalence of sleep and wakefulness disturbances in these patients. Along with the review of actual literature concerning mechanisms of development and clinical features of these disorders, the authors discuss principal methods for their treatment.

[The use of the parameters of chlorophyll a fluorescence induction for assessment of plant state under anthropogenic load].

The technique for recording of chlorophyll a fluorescence induction kinetics has been used for assessment of the physiological state of leaves of tillet (Tilia cordata), pendent white birch (Betula pendula), American arborvitae (Thuja occidentalis) in urban environments. Different sensitivity of plants to adverse growing conditions was observed. The most sensitive JIP test parameters such as PI(ABS), F(V)/F(0), F(V)/F(M), R(fd) are determined to be used as indicators of the physiological state of urban phytocenosis. Recommendations for the application of this technique in monitoring studies are given.

Role of ryanodine receptors in the effects of hydrogen sulfide on transmitter release from the frog motor nerve ending.

We studied the role of ryanodine receptors in the effects of hydrogen sulfide on transmitter release from frog motor nerve ending. Sodium hydrosulfide (300 µM), a donor of hydrogen sulfide, reversibly increased the frequency of miniature endplate current without changes in its amplitude-time parameters. These effects were associated with reversible increase in endplate current amplitude, which was abolished by activation of ryanodine receptors of intracellular Ca(2+)stores with caffeine (3 mM) and ryanodine (0.5 µM). Under conditions of ryanodine receptors blockade with ryanodine (10 µM), sodium hydrosulfide had no effect on induced transmitter release, but its effects remained unchanged during ryanodine receptors blockade with dantrolene (25 µM). We concluded that an enhanced acetylcholine release induced by hydrogen sulfide is related to an increase of intracellular Ca(2+)concentration due to activation of ryanodine receptors for intracellular Ca(2+)-pool.