Asymmetric DNA methylation between sister chromatids of metaphase chromosomes in mouse embryos upon bisphenol A action.

Earlier we showed that asymmetric methylation of sister chromatids (AMSC) was a specific characteristic of differentiation potency, and supposed that AMSC could be a useful marker of environmental impact connected with differentiation and/or dedifferentiation. Here we investigated the level of AMSC in chromosomes and the nuclei methylation in mouse preimplantation and postimplantation embryos, in comparison with the undifferentiated cells of mouse embryonal carcinoma cell line F9, and human differentiated HEK293 cells upon BPA influence. We found that exposure of mouse preimplantation embryos to BPA caused a significant decrease in the level of AMSC in chromosomes and the nuclei methylation.

[THE INFLUENCE OF THE PREPARATION PRETREATMENT ON IN SITU DETECTION OF 5-METHYLCYTOSINE IN METAPHASE CHROMOSOMES AND IN INTERPHASE NUCLEI].

Qualitative and quantitate analysis of DNA methylation in situ at the level of cells, chromosomes and chromosomal domains is extremely important for the diagnosis and treatment of various diseases, the study of ageing and the consequences of environmental impacts. An important question arises, whether the revealed in situ methylation pattern reflects DNA methylation per se and (or) availability of the DNA for antibodies, which in turn depends on the peculiarities of chromatin structure and chromosome condensation. These events can lead to an incorrect evaluation of the actual pattern of DNA methylation.

[[Length polymorphism of minisatellite repeat B2-VNTR of the bradykinin B2 receptor gene in healthy Russians and in patients with coronary heart disease].

Bradykinin B2 receptor is involved in many processes, including the regulation of blood pressure and smooth muscle contraction, vasodilation, inflammation, edema, cell proliferation, pain. It is suggested that this receptor may be one of the factors that have cardioprotective and infarct-limiting effects. It is assumed that certain genetic variants in both coding and non-coding regions ofBDKRB2 gene may influence its expression.

Influence of cooling rate on activity of ionotropic glutamate receptors in brain slices at hypothermia.

Hypothermia is a known approach in the treatment of neurological pathologies. Mild hypothermia enhances the therapeutic window for application of medicines, while deep hypothermia is often accompanied by complications, including problems in the recovery of brain functions. The purpose of present study was to investigate the functioning of glutamate ionotropic receptors in brain slices cooled with different rates during mild, moderate and deep hypothermia.

Effects of the blood components on the AMPA and NMDA synaptic responses in brain slices in the onset of hemorrhagic stroke.

Blood-borne events play a major role in post bleeding disturbances of the neuronal network. However, very little is known about the early effects of blood plasma, leucocytes, and the red blood cells on the AMPA and NMDA-mediated synaptic responses in the onset of experimental intracranial hemorrhage (ICH). In this study, we used the technique of on-line monitoring of electrophysiological parameters referred to synaptic activity in piriform cortex of SHR rat slice.

Effects of heparin on synaptic activity in the hemorrhagic stroke model in vitro.

We studied the ability of heparin to modify synaptic activity on the original stroke model in vitro. Cultured slices of the brain slices from hypertensive rats were treated with the autoblood clot. Administration of heparin (2 mg/ml) before autoblood treatment had a protective effect on ionotropic glutamatergic and GABAergic receptors, whose activity was inhibited by the blood.

Hsp70 promotes synaptic transmission in brain slices damaged by contact with blood clot.

Neurotrophic and neuroprotective properties of Hsp70 were studied in olfactory cortex slices of hypertensive rats under normal conditions and under influence of autologous blood (blood clot). Under normal conditions, synaptic response in slices depended on Hsp70 amount in medium. Incubation of slices with Hsp70 showed a biphasic effect on electrogenesis in tissue.

[Application of alpha-tocopherol acetate prevents swelling of brain slices during the autoblood clot action].

The swelling of olfactory cortex slices of the hypertensive SHR rats under the long autoblood action have been studied. The influence of a preincubation of slices with vitamins E, C and D on a degree of swelling have been detected by their weighing before and after exposure to autoblood. The water-soluble form of vitamin E have exerted a substantial antiswelling action exceeding the same of vitamin D, whereas vitamin C had no any effect.

Neuroprotective properties of l-carnosine in the brain slices exposed to autoblood in the hemorrhagic stroke model in vitro.

Neuroprotective properties of L-carnosine have been studied in our in vitro model on olfactory cortex slices of hypertensive rats under a long autoblood (blood clot) influence. Application of L-carnosine (5 mg/ml) on slices before autoblood influence leads to restoration of the activity of glutamatergic and GABA-ergic receptors inhibited in the presence of autoblood and interferes with swelling of slices. L-carnosine protects a bioelectric activity of nervous cells in case of long influence of autoblood and also renders an anti edema effect.

Effects of long-term exposure of nerve cells to autoblood in in vitro model of hemorrhagic stroke.

Changes in bioelectrical activity of nerve cells after their long-term exposure to autoblood were studied in vitro on cultured brain slices. This model simulated the events characteristic of a hemorrhagic stroke. Brain slice was placed into a glass vial with autoblood for 60-420 min, after which the slice was transferred into a perfusion chamber and after washing from autoblood their focal potentials were recorded.

Neurotropic effect of exogenous L-carnosine in cultured slices of the olfactory cortex from rat brain.

Incubation of cultured slices of the olfactory cortex from rat brain with L-carnosine in concentrations of 50, 250, and 500 M induced activation of glutamatergic and GABAB-ergic mechanisms and facilitated long-term posttetanic potentiation. The effect of L-carnosine is mediated by its effect on AMPA- and NMDA-related glutamatergic receptors and on inhibitory GABAB receptors.

[Development of edema in nervous tissue in the model of hemorrhagic stroke in vitro].

The development of edema in the surviving olfactory cortex slices by the control of bioelectric activity of neurons under the long-term influence of autoblood has been studied. The level of disturbance of neuronal activity was revealed by comparing focal potentials with their control values; the degree of tissue swelling was detected by their weighting before and at various time-points after exposure to autoblood. The use of this model of hemorrhagic stroke and pharmacological blockade of glutamate receptors allowed to find the correlation between the degree of edema in nervous tissue and the level of activity of ionotropic and metabotropic glutamate receptors.

[Hemorrhagic stroke: molecular mechanisms of pathogenesis and perspective therapeutic targets].

Key mechanisms of an induction and development of a hemorrhage insult are considered in the review. Action of the whole hemoglobin, products of blood destruction, and also the effects caused by nitric oxide are analyzed. The special attention is given to processes of a blood-brain barrier disruption, a water homeostasis and to development of a brain edema.

[Modeling of hemorrhage stroke in vitro].

A method of modeling of hemorrhage stroke suggested in the study includes the application of the autoblood on the surviving brain slices for 25-40 min followed by their washing. The parameters of evoked bioelectrical activity (focal potentials) of the slices are registered. The extent of nervous cells injury is established by comparing the focal potentials parameters in the control and during the blood application.

Heat shock protein HSP70 increases the resistance of cortical cells to glutamate excitotoxicity.

Preincubation of cultured slices of the olfactory cortex of rat brain with heat shock protein in a concentration of 1 microg/ml protected the pre- and postsynaptic mechanisms of glutamatergic synaptic transmission from glutamate excitotoxicity (50 mM) inducing blockade of excitatory postsynaptic function and reducing presynaptic processes. It was hypothesized that heat shock protein protects AMPA and NMDA receptor-mediated processes.

[Modification of rat behavioral reactions by peptides secreted by olfactory cortex cells upon their tetanization].

We studied neurotrophic properties of neuropeptide extracts from tetanized slices of the rat olfactory cortex. Two types of the extracts were studied, EP and ED, obtained from perfusates of the tetanized slices after long-term potentiation and from the slices after long-term depression, respectively. The effects of these two extracts were tested on rats using the open field and passive avoidance tests upon intranasal administration of the extracts (ca.

[Endogenous neuropeptides and regulation of the brain functional plasticity].

This review analysed the data about the neuropeptides secreted from the different brain structures. Involvement of the endogenous neuropeptides in synaptic plasticity was tested at the model of long-term potentiation (LTP) as a form of learning and the memory formation. The most of these neuropeptides or their fragments involves in the induction and maintenance of the LTP and provides the transformation of short-term excitability of the neurones into the long-term one.

Role of the phosphoinositide signal system and methylation of phosphatidylethanolamine in the development of long-term post-tetanic potentiation in rats.

High-frequency stimulation eliciting long-term post-tetanic potentiation of neuronal excitation in slices of the rat olfactory cortex was accompanied by changes in the metabolism of phospholipid components of cell membranes. At the first stage of the development of long-term potentiation (10 min after tetanization), there was a reduction in phosphoinositide metabolism. The maintenance phase of the potentiated state (30 min after tetanization) was associated with a three-fold increase in the incorporation of 14C-labeled groups from adenosylmethionine into phosphatidylethanolamine methylation products and with normalization of phosphoinositide metabolism.

[The role of the phosphoinositide signal system and phosphatidylethanolamine methylation in the development of long-term posttetanic potentiation in rats].

A long-term potentiation of the rat olfactory cortex slices induced by a high-frequency stimulation is followed by membrane phospholipid changes. Activation of the phosphoinositide metabolism and normalising of phosphatidylethanolamine methylation occurs within 60 min after tetanisation when the potentiation fades. The findings reveal a regulating role of the phospholipid signal system at different stages of the long-term potentiation.

The influence of picrotoxin on the methylation of phospholipids of the olfactory cortex of the brain of rats.

It was demonstrated that a decrease in the intensity of methylation of phosphatidylethanolamine in sections of rat olfactory cortex is observed 15 min following the introduction of picrotoxin (10(-5) M) into the incubation medium. The decrease in the intensity of methylation of phospholipids may be closely linked to the opening of ion channels, since it is known that maximal depolarization of the membranes is observed during this period of the effect of the preparation.

[The coupling of phosphoinositide metabolism sensitive to ACTH with the adenylate cyclase system in the synaptosomes].

The effect of cAMP on the phosphoinositide metabolism increased by the ACTH, was studied in the rat brain synaptosomes. The data obtained suggest that a coupling of the phosphoinositide metabolism and the adenylate cyclase system occurs under these conditions.