Correlation analysis of vibration modes in physical vapour deposited Bi2Se3 thin films probed by the Raman mapping technique.

In this work, the Raman spectroscopy mapping technique is used for the analysis of mechanical strain in Bi2Se3 thin films of various (3-400 nm) thicknesses synthesized by physical vapour deposition on amorphous quartz and single-layer graphene substrates. The evaluation of strain effects is based on the correlation analysis of in-plane (E2 g) and out-of-plane (A2 1g) Raman mode positions. For Bi2Se3 films deposited on quartz, experimental datapoints are scattered along the line with a slope of ∼0.85, related to the distribution of hydrostatic strain. In contrast to quartz/Bi2Se3 samples, for graphene/Bi2Se3 heterostructures with the same thicknesses, an additional negative slope of ∼-0.85, which can be associated with the distribution of the in-plane (a-b) biaxial tensile strain due to the film-substrate lattice mismatch, is observed. The algorithm of phonon deformation potential (PDP) calculation based on the proposed strain analysis for the 3 nm thick Bi2Se3 film deposited on the graphene substrate, where the strain is considered to be coherent across the thickness, is demonstrated. The PDPs for biaxial in-plane strain of the Bi2Se3 3 nm film in in-plane and out-of-plane modes are equal to -7.64 cm-1/% and -6.97 cm-1/%, respectively.

[Lack of antidepresant-like activity of some ligands of polyamine binding sites of NMDA receptors in models of depression].

Arcain and a series of the partial modulators of polyamine binding sites of NMDA receptors (spermine- and adamantyl-containing polyamines IEM-1460, IEM-1490, IEM-1592, IEM-1755) do not display (in contrast to melipramine and memantine) antidepressant-like action in the forced swimming test and reserpine-induced depression test in rats. Compounds IEM-1460, IEM-1490, IEM-1592 increase the total time of immobilization in the Porsolt test, probably, by facilitating the development of stress-induced depression. It is supposed that the prodepressant activity of these compounds is mediated by NMDA-receptors having NR1/NR2C and NR1/NR2D subunit composition.

[Comparison of anti-amnesia properties of NMDA-receptor "fast" blockers and polyamines]. / Sravnitel'naia otsenka antiamnesticheskikh svoistv "bystrykh" blokatorov NMDA-retseptorov i poliaminov.

The experiments on rats showed that IEM-1460, IEM-1490, and IEM-1755 (bisammonium adamantyl-containing compounds possessing fast NMDA channel blocking activity) and polyamines (spermine and arcain) do not alter acquiring of the passive avoidance reaction. All these compounds improve, albeit with different efficacy, the memory traces impaired by scopolamine and/or electroshock: IEM-1755 eliminated amnesia induced by the electroshock, but enhanced the amnesia evoked by scopolamine. Arcain inhibited (for a short time and in a narrow dose range) the antiamnesic effect of IEM-1460. It is suggested that the antiamnesic effect of compounds from both groups is related to the ability of slowing down the NMDA receptor desensitization.

Inhibitory action of ambocarb on voltage-operated sodium channels in rat isolated hippocampal pyramidal neurons.

1. A whole-cell patch-clamp study of the effects of ambocarb, a novel nootropic beta-carboline, on sodium currents in rat acutely isolated hippocampal pyramidal neurons was performed. 2. Ambocarb potently and reversibly suppressed sodium currents in a concentration range of 3-300 mumol/L. The amount of block was dependent on the holding potential, with half-maximal inhibition values being 26 and 94 mumol/L at -80 and -120 mV, respectively. 3. Ambocarb induced a hyperpolarizing shift in the steady state availability curve, which indicates an increase in the proportion of inactivated sodium channels. This action is presumably mediated by promoting the development of inactivation and slowing the recovery of sodium channels from inactivation. 4. Because many neuroprotective drugs were shown to inhibit sodium currents, down-modulation of voltage-operated sodium channels that complements the known positive interaction of ambocarb and other related beta-carbolines with GABAA receptors may provide a promising strategy in the treatment of brain disorders associated with trauma and ischaemia.

[The different mechanism of the inhibition by buspirone and its camphorimide analogs of 5-HT3-serotoninergic effects]. / Raznyi mekhanizm ingibirovaniia buspironom i ego kamforimidnymi analogami 5-HT3-serotoninergicheskikh éffektov.

Serotonin evokes the depolarization and the membrane resistance lowering of rat dorsal root ganglion neurones when a K(+)--conductance of the neuronal membranes is blocked by Cs+ intracellular injection. These 5-HT3-effects ere diminished and removed by preliminary superfusion of the ganglions with saline containing busperone or its structural analogues. The effects of camphorimide analogues of buspirone (campirone, pyricapirone) could not be reproduced in case of the protein kinase A blockade by tolbutamide (100 microM/l). It is suggested that camphorimide analogues are the 5-HT3 receptor blockers while busperone and ipsapirone modulate 5-HT3 receptor affinity by decreasing the protein kinase A activity.

[Lithium ion modulation of the neuronal responses evoked by monoaminergic receptor agonists]. / Moduliatsiia ionami litiia otvetov neironov, vyzyvaemykh agonistami monoaminergicheskikh retseptorov.

The authors studied the action of lithium ions on the responses of rat dorsal root ganglion neurons and frog spinal motoneurons evoked by monoamine agonists using the microelectrode technique. Lithium ions reversibly inhibit the depolarizing responses of spinal sensory neurons and motoneurons evoked by activation of muscarinic choline-, alpha 1-adreno-, and 5-hydroxytryptamine2 receptors, but enhance the hyperpolarizing neuronal responses evoked by activation of 5-hidroxytryptamine1A receptors.

[The role of the chemosensory systems in the inhibitory regulation of cholinergic transmission in the small intestine]. / Rol khemosensornykh sistem v tormoznoi reguliatsii kholinergicheskoi peredachi v tonkoi kishke.

The double bath method has been used to study reflex inhibition of cholinergic transmission in the guinea-pig ileum segment. It is shown that adenosine, noradrenaline, 5-methylfurmethide as well as acute hypoxia, which affect the oral part of the intestine are able to evoke two kinds of effects in its anal part firstly, the depression of cholinergic transmission, and secondly, the stimulation of non-adrenergic, non-cholinergic contractions. A preliminary treatment with capsaicin and with hexamethonium on the oral part of the gut prevents these effects, and the chymotrypsin abolishes these effects. A mechanism of this reflex descending inhibition of cholinergic transmission is realised apparently through the stimulation of the chemoreceptors in afferent capsaicin-sensitive nerves with participation of cholinergic interneurons and activation of the inhibitory, most probably vasoactive intestinal peptidergic (VIP) neurons in the enteric plexuses.

[Nootropic drugs potentiate nerve cell responses evoked by NMDA-glutamate receptor activation]. / Nootropy potentsiruiut otvety nervnykh kletok, vyzyvaemye aktivatsiei NMDA-glutamatnykh retseptorov.

The nootropic drugs--nootropil, aethimizol, diethylaminoethanol, and ambocarb diminished of amnesia of active avoidance habit evoked by maximal electroconvulsive shock in the rats. At the same time tested nootropic drugs potentiated the frog spinal motoneurons responses mediated by NMDA, but not non NMDA glutamate receptors activation. It was discussed the role of NMDA-potentiating nootropic drugs action in their anti-amnestic action.

[Effects of serotonin-IA receptors on amino acid and dopaminergic responses of neurons]. / Vliianie agonistov serotoninovykh-IA retseptorov na aminoatsid- i dofaminergicheskie otvety neironov.

By using intracellular technique the authors studied the responses of frog spinal motoneurones and rat dorsal root ganglion evoked by GABA, L-aspartate and dopamine in the presence of 5-hydroxytryptamine and its 1A-agonists or without them. It is shown that buspirone, campirone and serotonin increase the GABA effects but inhibit the effects of aspartate via the GABA- and NMDA-receptors modulation.

[Effects of buspirone and buspirone-like 1-A-agonists of serotonin on the level of systemic blood pressure]. / Vliianie buspirona i buspironopodobnykh 1A-agonistov serotonina na uroven' sistemnogo arterial'nogo davleniia.

Experiments on anaesthetized rats showed that buspirone, its structural analogies (ipsapirone, campirone and levopirone) and active metabolite 1-(2-pyrimidinyl)-piperazine (0.1-30 mg/kg i.v.) produced bradycardia, hyperpnea and changed the arterial pressure level. Arterial pressure either increased or decreased that was determined by its initial level. The hypotension produced by all these drugs was of a central origin and mediated by hydroxytryptamine-1A-receptors. The pressor response resulted from activation of predominantly hydroxytryptamine-2-receptors of vascular smooth muscles.

[Postsynaptic metabolic monoamine modulation of effects mediated by NMDA glutamate receptors in spinal motoneurons of the frog]. / Postsinapticheskaia metabolicheskaia moduliatsiia monoaminami éffektov, oposreduemykh NMDA-glutamatnymi retseptorami, v spinal'nykh motoneironakh liagushek.

Monoamines, their agonists and antagonists have been investigated for their influence on responses of spinal motoneurons in frog mediated by NMDA-glutamate receptors (late components of dorsal root polysynaptic EPSP's and depolarizing responses evoked by L-aspartate). Monoamine responses which promoted an increase of intracellular concentration of cAMP and Ca2+ in the motoneurons (activation of alpha- and beta-adrenoreceptors, D1-dopamine and 5-hydroxytryptamine-receptors) reinforced the studied spinal motoneuron responses of frog. These responses were weakened by the monoamine action which led to a decrease of the intracellular concentration of cAMP and Ca2+ (activation of D2-dopamine and 5-hydroxytryptamine1A-receptors). The monoamine effects were inhibited by specific monoamine antagonists, tolbutamide and trifluoperazine. It is supposed that NMDA receptor-channel complex is exposed by cAMP- and Ca(2+)-calmodulin-dependent phosphorylation induced by activation of membrane monoamine receptors.

[The correlation of the serotonin-positive and anxiolytic activities of nonbenzodiazepine substances]. / Korreliatsiia serotoninpozitivnoi i anksioliticheskoi aktivnosti nebenzodiazepinovykh veshchestv.

The anxiolytic activity of serotonin agonists (buspirone, ipsapirone, campirone, caplapirone, 1-pyrimidinyl-piperazine) determined in rats on 3 experimental models of anxiety closely correlates with the degree of inhibition of impulse release of 3H-serotonin by electrically stimulated slices of the midbrain raphe dorsal nucleus (r = +0.85) but not the slices of the cerebral hemispheric cortex (r = +0.60) of the rats. The anxiolytic activity of neuroleptics (chlorpromazine, trifluorperazine), antidepressant (amitriptyline, imipramine) and beta-carbolines (harmane, 3.4-tetramethyleneharmane) corresponds well (r = +0.94) to the ability of the drugs to potentiate the hyperpolarizing effects of serotonin in the rat sensory ganglion.

[An analysis of the hypothermic action of 8-hydroxy-2-(di-N-propylamino)tetralin, 1-(2-pyrimidinyl)piperazine and its derivatives]. / Analiz gipotermicheskogo deistviia 8-oksi-2-(di-N-propilamino)--tetralina, 1-(2-pirimidinil)--piperazina i ego proizvodnykh.

The hypothermic activity of 8-OH-DRAT, 1-(2-pyrimidinyl) piperazine (1-PP), buspirone and its structure analogues tightly correlates with the degree of inhibition of 3H-serotonine release by electrically stimulated dorsal raphe slices (r = 0.84), but not cerebral cortex slices (r = 0.66). The pretreatment of mice with p-chlorphenylalanine decreased the hypothermic effects evoked by 8-OH-DRAT, buspirone, campirone (but not 1-PP) only in first 30 min after there injection. It was concluded that hypothermic effects of 8-OH-DRAT, buspirone and its structure analogues were bound with preferable influence as partial agonists on the postsynaptic serotonine 1A receptors. Ipsapirone as a partial agonist has maximal antagonistic activity.