[CHEMICAL COMPONENTS FROM STEMS ASTRAGALUS FALCATUS, GROWING IN GEORGIA].

Astragalus falcatus is the source of medicinal remedy Flaroninum, also other biologically active substances. Eight compounds were isolated and identified from the of stems : calycosin-7-O- ß -D - glucoside, isoquercitrin (quercetin-3-O - ß -D- glucoside), astragalin (kaempferol-3-O - ß -D- glicoside), robinin (kaempferol-3- O- ß -D- robinobiosyl, 7- O- a-L-rhamnoside), ß - sitosterin, p-hydroxibenzoic acid, sulfuretin and isoliquiritigenin. These compounds were described for the first time from the stems of Astragalus falcatus.

[RESULTS OF THE PRELIMINARY STUDY OF PLANTS OF GEORGIAN FLORA FOR THE CONTENT OF FLAVONOIDS AND TRITERPENOIDS].

The aim of the study was a preliminary study of plant samples collected by targeted expeditions of the department of pharmacobotany (Department of Phytochemistry) of the IG Kutateladze Institute of Pharmacochemistry for the period 2016-2017. In total, 341 objects from (106 various) plants belonging to 36 families and 93 genus were analyzed. The objects were obtained polar and non-polar fractions; flavonoids and triterpenoids were found in them qualitatively. To characterize used P /CH and TLC analysis in various solvent systems. Flavonoids were isolated from Geranium ibericum and Polygonum carneum, which were identified as quercetin-3-0-ß-D-galactopyranoside-hyperin (G. ibericum), 3 5, 7 ', 3'.4' pentahydroxy-flavone - quercetin (G. ibericum, P. сarneum) and quercetin-3-0-rutinozide - rutin (P. сarneum). G. ibericum and P.carneum flora of Georgia are found and studied for the first time. Representatives of the family Asteraceae, Fabaceae, Helleboraceae, Polygonaceae, Scrophula riaceae deserve a particular interest in the content of triterpenoids.

Thickness dependence of scattering cross-sections in quantitative scanning transmission electron microscopy.

In quantitative scanning transmission electron microscopy (STEM), scattering cross-sections have been shown to be very sensitive to the number of atoms in a column and its composition. They correspond to the integrated intensity over the atomic column and they outperform other measures. As compared to atomic column peak intensities, which saturate at a given thickness, scattering cross-sections increase monotonically. A study of the electron wave propagation is presented to explain the sensitivity of the scattering cross-sections. Based on the multislice algorithm, we analyse the wave propagation inside the crystal and its link to the scattered signal for the different probe positions contained in the scattering cross-section for detector collection in the low-, middle- and high-angle regimes. The influence to the signal from scattering of neighbouring columns is also discussed.

Frozen lattice and absorptive model for high angle annular dark field scanning transmission electron microscopy: A comparison study in terms of integrated intensity and atomic column position measurement.

In this paper, both the frozen lattice (FL) and the absorptive potential (AP) approximation models are compared in terms of the integrated intensity and the precision with which atomic columns can be located from an image acquired using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM). The comparison is made for atoms of Cu, Ag, and Au. The integrated intensity is computed for both an isolated atomic column and an atomic column inside an FCC structure. The precision has been computed using the so-called Cramér-Rao Lower Bound (CRLB), which provides a theoretical lower bound on the variance with which parameters can be estimated. It is shown that the AP model results into accurate measurements for the integrated intensity only for small detector ranges under relatively low angles and for small thicknesses. In terms of the attainable precision, both methods show similar results indicating picometer range precision under realistic experimental conditions.

How precise can atoms of a nanocluster be located in 3D using a tilt series of scanning transmission electron microscopy images?

In this paper, we investigate how precise atoms of a small nanocluster can ultimately be located in three dimensions (3D) from a tilt series of images acquired using annular dark field (ADF) scanning transmission electron microscopy (STEM). Therefore, we derive an expression for the statistical precision with which the 3D atomic position coordinates can be estimated in a quantitative analysis. Evaluating this statistical precision as a function of the microscope settings also allows us to derive the optimal experimental design. In this manner, the optimal angular tilt range, required electron dose, optimal detector angles, and number of projection images can be determined.

Depth sectioning combined with atom-counting in HAADF STEM to retrieve the 3D atomic structure.

Aberration correction in scanning transmission electron microscopy (STEM) has greatly improved the lateral and depth resolution. When using depth sectioning, a technique during which a series of images is recorded at different defocus values, single impurity atoms can be visualised in three dimensions. In this paper, we investigate new possibilities emerging when combining depth sectioning and precise atom-counting in order to reconstruct nanosized particles in three dimensions. Although the depth resolution does not allow one to precisely locate each atom within an atomic column, it will be shown that the depth location of an atomic column as a whole can be measured precisely. In this manner, the morphology of a nanoparticle can be reconstructed in three dimensions. This will be demonstrated using simulations and experimental data of a gold nanorod.

Orexinergic system and pathophysiology of epilepsy.

Neuropeptids orexins, also known as the hypocretins, are expressed in the lateral hypothalamus. Orexin-containing cells project widely throughout the brains, are crucial for the regulation of wakefulness and dysfunction of this system is associated with pathophysiology of narcolepsy-cataplexy. Orexin neurons play an important role in motivation, feeding and adaptive behaviors. Distribution of orexinergic receptors in the hippocampus tended to the ideas that orexins might be involved in the functions relating to the hippocampus. Effects of neuropeptide orexin-A on epileptiform activity in hippocampal slices were investigated. 500 µm thick hippocampal slices from 8-10 week-old rodents were used. Field excitatory postsynaptic potential (pop-fEPSP) and population spike in CA1 of hippocamopus were registered using standard protocol of in vitro electrophysiological experiments. Initial slope of the fEPSP and amplitude of II pop-spike were measured. Bursting neurons in CA3 were recorded in modified saline. We have found that orexin-A decreases duration/amplitude of multiple discharges of pop-spikes and inhibits spontaneous epileptiform afterdischarges induced by bicuculline methiodide in CA1. Orexin-A also modulates the frequency of discharges of bursting neurons in CA3. Our results suggest possible involvement of orexinergic system in antiepileptic action. Supported by ISTC Grant G-1318.

Orexin-A induces long-term depression of nmda responses in CA-1 field of hippocampal slices.

We have studied the effects of orexin-A on NMDA component of registered field potentials in pyramidal (str. pyramidale) and radial layers (st. radiatum) of CA-1 field of the hippocampus. To facilitate generation of NMDA responses in vitro experiments were performed in Mg(2+)- free solution. From field excitatory postsynaptic potential (EPSP), which was induced by stimulation of Schaffer collaterals, NMDA component was isolated using modified physiological solution: bicuculline metiodide (20-40 microM) and CNQX (5 microM) were eddied for removing GABA-ergic inhibition and blocking AMPA-glutamatergic receptor-mediated responses, respectively. Application of orexin-A (100 nM, for 5 -15 min) evoked inhibition of NMDA component of population spike (84.4+/-5%, n=7) and long-term depression of isolated NMDA component of field EPSP, which was made up (77.7+/-2.8%, n=12) comparing with control after 45 min of orexin-A application. Orexin-A mediated depression starts after 7-10 min of application, which is sufficient for NE release from adrenergic terminals in the hippocampus. As the agonist of alpha-adrenoreceptors clonidine completely mimicked the effects of orexin-A possible involvement of adrenergic system of the brain in these effects are considered.

The role of the mGluR allosteric modulation in the NMDA-hypofunction model of schizophrenia.

Schizophrenia is one of the most important forms of psychiatric illness and may be chronic and highly disabling. It has been suggested that specific neurochemical abnormality is due to dopaminergic overactivity in the brain. Schizophrenia is currently thought to be associated with a hypoglutamatergic state that is mimicked by acute Phencyclidine (PCP), an antagonist of the N-methyl-D-aspartate (NMDA) receptor subtype. Administration of PCP or ketamine in rodents has been used to model aspects of schizophrenia. Taken into consideration the role of glutamatergic system in development of schizophrenia and involvement of striatal dopaminergic receptors in generation of schizophrenia symptoms, it was planned to study functional interaction between NMDA and metabotropic glutamatergic receptors 5 (mGluR5) in schizophrenia-associated behavioral and memory disturbance and the role of mGluRs allosteric modulation in cortico-striatal synaptic plasticity. In our experiments investigation of dose-dependent effects of ketamine revealed that 0.3mg/kg ketamine induces statistical changes most of behavioral and cognitive parameters in rats. Changes in emotional state showed decrease of the number and total duration of groomings in open field experiments as wall as in passive avoidance task. Decrease of motor activity was also detected, while no significant changes were observed in number of defecations. In T-maze test it was shown that spatial memory was damaged. To determine whether mGlu5 and NMDA receptor interact to regulate complex behaviors that are relevant to cognitive disorders such as schizophrenia we focused on assessing whether the selective mGlu5 receptor antagonist 2-methyl-6-(phenylethynyl)-pyridine MPEP mimics or exacerbates the effects of the NMDA receptor antagonist. Ketamine-induced memory disturbance was significantly increased after injection of mGluR5 negative allosteric modulators MPEP. In In vitro experiments the agonist at group I metabotropic glutamate receptors (mGluRI) (RS)-3,5-dihydroxyphenyl-glycine (DHPG,100 microM) evoked a persistent depression of the second component (N2) of the cortico-striatal field potential in rat slices. DHPG-induced plasticity was not NMDA-dependent. mGlu5 negative allosteric modulator MPEP diminishes the inhibition of synaptic responses induced by DHPG and completely blocked the late phase of depression. Our behavioral and in vitro data suggested that between NMDA and mGlu5 receptors there are functional interaction. Thus in some neurological or psychiatric disorders with NMDA dysfunction pharmacological manipulation of mGlu5 receptors could have therapeutic use.

Multilevel inhibition of feeding by a peptidergic pleural interneuron in the mollusc Lymnaea stagnalis.

The pleural interneuron PlB is a white neuron in the pleural ganglion of the snail Lymnaea. We test the hypothesis that it inhibits neurons at all levels of the feeding system, using a combination of anatomy, physiology and pharmacology. There is just one PlB in each pleural ganglion. Its axon traverses the pedal and cerebral ganglia, running into the buccal ganglia. It has neuropilar branches in the regions of the cerebral and buccal ganglia where neurons that are active during feeding also branch. Activation of the PlB blocks fictive feeding, whether the feeding rhythm occurs spontaneously or is driven by a modulatory interneuron. The PlB inhibits all the neurons in the feeding network, including protraction and retraction motoneurons, central pattern generator interneurons, buccal modulatory interneurons (SO, OC), and cerebral modulatory interneurons (CV1, CGC). Only the CV1 interneuron shows discrete 1:1 IPSPs; all other effects are slow, smooth hyperpolarizations. All connections persist in Ca(2+)/Mg(2+)-rich saline, which reduces polysynaptic effects. The inhibitory effects are mimicked by 0.5 to 100 micromol l(-1) FMRFamide, which the PlB soma contains. We conclude that the PlB inhibits neurons in the feeding system at all levels, probably acting though the peptide transmitter FMRFamide.

On statistical relationship of solar, geomagnetic and human activities.

Data of galactic cosmic rays, solar and geomagnetic activities and solar wind parameters on the one side and car accident events (CAE) in Poland on the other have been analyzed in order to reveal the statistical relationships among them for the period of 1990-2001. Cross correlation and cross spectrum of the galactic cosmic ray intensity, the solar wind (SW) velocity, Kp index of geomagnetic activity and CAE in Poland have been carried out. It is shown that in some epochs of the above-mentioned period there is found a reliable relationship between CAE and solar and geomagnetic activities parameters in the range of the different periodicities, especially, 7 days. The periodicity of 7 days revealed in the data of the CAE has the maximum on Friday without any exception for the minimum and maximum epochs of solar activity. However, the periodicity of 7 days is reliably revealed in other parameters characterizing galactic cosmic rays, SW, solar and geomagnetic activities, especially for the minimum epoch of solar activity. The periodicity of 3.5 days found in the series of CAE data more or less can be completely ascribed to the social effects, while the periodicity of 7 days can be ascribed to the social effect or/to the processes on the Sun, in the interplanetary space and in the Earth's magnetosphere and atmosphere.

Statistical analyses of influence of solar and geomagnetic activities on car accident events.

Statistical analyses of the influence of Solar and geomagnetic activity, sector structure of the interplanetary magnetic field and galactic cosmic ray Forbush effects on car accident events in Poland for the period of 1990-1999 have been carried out. Using auto-correlation, cross-correlation, spectral analyses and superposition epochs methods it has been shown that there are separate periods when car accident events have direct correlation with Ap index of the geomagnetic activity, sector structure of the interplanetary magnetic field and Forbush decreases of galactic cosmic rays. Nevertheless, the single-valued direct correlation is not possible to reveal for the whole period of 1990-1999. Periodicity of 7 days and its second harmonic (3.5 days) has been reliably revealed in the car accident events data in Poland for the each year of the period 1990-1999. It is shown that the maximum car accident events take place in Poland on Friday and practically does not depend on the level of solar and geomagnetic activities.

Morphology and physiology of pleural-to-buccal neurons coordinating defensive retraction with feeding arrest in the pond snail Lymnaea stagnalis.

1. We have studied morphology, physiology and chemistry of a bilateral pair of pleural-to-buccal projecting neurons (PlB cells) of the pond snail Lymnaea stagnalis. Intracellular dye fills revealed axon arborization within neuropiles of ipsilateral pedal and cerebral ganglia, as well as in both buccal ganglia. Terminal axons of the left and right PlBs showed close proximity within the buccal commissure. 2. The left and right PlB neurons have been found electrotonically coupled and, sometimes, generating synchronous spikes. 3. The results show that two PlB cells operate as a single unit, and that paired buccal networks responsible for feeding rhythm are treated by the PlBs as a single target.

Pleuro-buccal projections in pulmonate molluscs.

Using a nickel lysine axonal filling technique, neurons of the CNS that project to the cerebro-buccal connective in pulmonate snails and slugs were stained. In all species examined, a symmetrical, supposedly homologous pair of small neurons situated in the pleural ganglia have been identified. These neurons possess a unique axonal pathway which traverses the ipsilateral pedal ganglion on its way to the cerebral ganglia. The list of species includes both basomatophoran, fresh-water molluscs (Lymnaea stagnalis, L. auricularia, Planorbarius corneus) and stylommatophoran, terrestrial ones (Fruticicola fruticum, Helix pomatia, H. lucorum, Limax cinerea-niger). It is suggested that the paired pleural cells might be involved in the neuronal mechanism for co-ordination of defensive withdrawal with inhibition of feeding.