[Protein-Protein Interactions of Huntingtin in the Hippocampus].

Huntingtin (HTT) occurs in the neuronal cytoplasm and can interact with structural elements of synapses. Huntington's disease (HD) results from pathological expansion of a polyglutamine stretch in the HTT molecule, being probably associated with aberrant protein-protein interactions. The pathogenetic mechanism is still incompletely understood.

Amide of Lambertian Acid Suppresses Hyperactivation of Inotropic Glutamate Receptors, but not Synaptic Potentiation in Hippocampal Sections.

Amide of lambertian acid suppresses hyperactivation of inotropic glutamate receptors in hippocampal sections induced by a decrease in the level of magnesium ions (a selective blocker of glutamate NMDA receptors). Treatment of the sections with amide of lambertian acid in standard physiological saline does not prevent development of NMDA-dependent synaptic potentiation. Lambertian acid isolated from needles and turpentine of Siberian pine (Pinus sibirica R.

[MOBILITY OF AMPA SUBTYPE GLUTAMATE RECEPTOR AS A KEY FACTOR OF EXPRESSION AND MAINTENANCE OF SYNAPTIC POTENTIATION].

A time dynamic of LTP development in the first minutes after high frequency stimulation has been investigated by using a cell model of synaptic potentiation. An experimental assessment of dependence of potentiation and maintenance of a stable level of synaptic transmission in the CA1 area of mice hippocampus on the intracellular transport has been made with brefeldin A (the blocker of transport vesicle forming). The integrative activity of the systems, ensuring the delivery of glutamate receptors to the dendrite spines in amounts and in time intervals necessary for fast changing and long maintenance of transmission efficiency is discussing.

Different effects of α- and γ-glycine on the aberrant activity of pyramidal neurons of hippocampal slices.

Experiments in vitro on hippocampal slices of mouse have shown that solutions prepared from polymorphic modifications α- and γ-glycine have different effect on the aberrant activity of neurons. In the presence of α-glycine the excitability of these neurons decreased more slowly, prolonging its modulating effect on NMDA type glutamate receptors. This effect agrees with higher biological activity of α-polymorphic modifications (as compared with that of the α-form) that previously observed with respect to behavior of mice from the line with genetic diathesis to catalepsy, which were used as a biological model for investigation of some pathological behavior forms.

The correlation between tick (Ixodes persulcatus Sch.) questing behaviour and synganglion neuronal responses to odours.

We examined the behavioural and electrophysiological responses of taiga ticks (Ixodes persulcatus) to several olfactory stimuli: Osmopherone® (5-a-androst-16-en-3-ol), Osmopherine® (butanoic and 3-methylbutanoic acids), DEET® (N,N-diethyl-meta-toluamide), ethanol (96%), and water (control stimulus). To study individual tick behavioural reactions to these stimuli, we used a Y-shaped glass maze (n=50). To study the electrophysiological reactions of the ticks' synganglia to these olfactory stimuli, we recorded the shifts of total potential (TP) of pre-oesophageal neurons in response to odour stimulation of Haller's organ (n=25).

Principles of cellular-molecular mechanisms underlying neuron functions.

In the present work, it was experimentally shown that a neuron in vitro was capable of responding in a manner similar to habituation, Pavlov's reflex and avoidance of the reinforcements. The locality of plastic property modifications and molecular morphology, as well as the connection between functional activity and cytoskeleton have been revealed. A hypothesis is formulated that the neuron is a molecular system which may exercise the control, forecast, recognition, and classification.

[Influence of terahertz (submillimeter) laser radiation on neurons in vitro].

The development of new sources of coherent non-ionizing radiation in terahertz wave range put forward the basic problems of revealing the mechanism of its action on biological objects, especially, on the nervous system. At this point it is necessary to reveal the radiation effects on complex molecular systems such as nerve cells. It was the main objective of this study.

Substances in subthreshold concentrations under stress conditions can act as conditioned stimuli and trigger defense reactions.

The capacity of living systems to perceive low-intensity stimuli sometimes inducing protective reactions is still little studied. Incubation of neurons under conditions increasing the content of cAMP and Ca(2+) increases the amplitude of their responses to lidocaine (10(-3) M). After cell preconditioning with low concentrations of lidocaine (10(-15) M) under these conditions, the protective effects of "ineffective" concentrations were detected, because the response amplitude did not decrease.

Effects of histochrom and emoxypin on biophysical properties of electroexitable cells.

Comparative investigation of effects of antioxidant agents histochrom and emoxypin on biophysical characteristics of isolated neurons from shell Lymnaea stagnalis under normal conditions and during oxidative stress was performed. Differently directed effects of these compounds on resting potential and transmembrane ion currents of neural cells under normal conditions were detected. Histochrom provides hyperpolarizing and emoxypin--depolarizing effect on neuronal membrane potential.

Epileptiform activity in the hippocampus of mice with different predisposition to pinch catalepsy.

Experiments on hippocampal slices of CBA mice showed that the probability of spontaneous epileptiform discharges recorded in the field CA1 pyramidal layer is higher in animals predisposed to catalepsy compared to mice with low predisposition to catalepsy. Presumably, some factors determining predisposition to catalepsy modulate synchronization of neuronal activity in the hippocampus; this suggests using hippocampal slices as a model for studies of neurophysiological mechanisms of hereditary predisposition to catalepsy.

Seasonal differences and protection by creatine or arginine pretreatment in ischemia of mammalian and molluscan neurons in vitro.

We investigated the dose-response relationship of protection by creatine against ischemic damage, and we asked whether or not such protection may be observed in invertebrate neurons that might provide a simpler experimental model. Rat isolated pyramidal neurons from the CA3 region of hippocampus subjected to ischemia ("in vitro ischemia") showed anoxic depolarization (AD) after 3-7 min of incubation in anoxic medium. Membrane potential (MP) was reduced 25-78% from preanoxic value.

Plasticity of neuronal responses induced by low concentrations of exogenous ligands affecting cellular calcium stores.

Modification of reactions caused by repeated influences (plasticity) is a fundamental property of cell. In this study, we have revealed effects of low concentrations of two exogenous modulators of cellular processes (caffeine and cyclosporin A) on neuronal plastic properties. The study was carried out on isolated neurons of Lymnaea stagnalis.

Reaction of neurons to alkaloid agonists of opioid receptors during modulation of phosphodiesterases.

We studied the effect of ultralow doses of theophylline and morphine, modulators of receptors and intracellular signal systems, on ion permeability of membranes. Theophylline and morphine in ultralow doses blocked the neuronal responses to these agents applied in physiological concentrations. Theophylline in ultralow doses attenuated, but did not completely block neuronal reaction to morphine.

The effects of the dynamic state of the cytoskeleton on neuronal plasticity.

The effects of degrading and stabilizing microtubules and microfilaments on the formation of plastic reactions were studied in isolated nerve cells from the mollusk Lymnaea stagnalis. Degradation of the cytoskeleton affected the performance, retention, and repeated acquisition of plastic reactions. Stabilization of microtubules led to the appearance of a relationship between the dynamics of the development and retention of plastic reactions and the series of stimulation.

[Effect of the cytoskeleton dynamic condition on the neuronal plasticity].

Infringement of the Lymnaea stagnalis cytoskeleton condition affected preservation and repeated development of plastic responses. Stabilising of the microtubules led to a dependence of the development and preservation dynamics of the plastic responses. Stabilising of the microfilaments transformed short-term plastic responses into long-term ones.

Effects of changes in dynamic equilibrium in microtubule and microfilament systems on the plastic responses of neurons.

Studies were carried out on the effects of disruption and stabilization of microtubules and microfilaments on the formation of neuronal plastic responses in isolated nerve cells of the mollusk Lymnaea stagnalis. Disruption of these cytoskeletal elements prevented the development of neuronal plastic responses. Microtubule stabilization produced a dynamic relationship between the development and retention of neuronal plastic responses and series of stimuli.

[The effect of changes in the dynamic equilibrium in the microtubular and microfilamentous systems on neuronal plastic reactions].

Effects of disruption or stabilization of microfilaments or microtubules on formation of neuronal plastic reactions (NPR) were studied in isolated Lymnaea stagnalis neurons. Disruption of these cytoskeletal elements blocked the development of the NPR. After stabilization of the microtubules the dynamics of development and retention of the NPR became dependent on the stimulation series.

[Changes in the neural activity of the blood serum from patients with ischemic heart disease].

The isolated neurons of snail (Lymnaea stagnalis) were as test object for the evaluation of the blood serum neuroactivity. The blood serum was tested before treatment and after six applications of intravenous laser therapy (ILT). All blood serum specimens produced depolarization of the cell membrane potential.