[Behavioral and neuroreceptor effects of the racetam derivative GIZh-290 in mouse experimental attention deficit model]. / Povedencheskie i neiroretseptornye éffekty proizvodnogo ratsetama GIZh-290 s ispol'zovaniem éksperimental'noi modeli defitsita vnimaniia.

Behavioral and neurochemical effects of the new racetam derivative GIZh-290 were studied in a mouse attention deficit model (the ED-Low animals subpopulation selected during preliminary behavioral typing in the "closed enriched cross maze" test). Subchronic administration of GIZh-290 (1 mg/kg, 3 mg/kg and 5 mg/kg, intraperitoneally, for 6 days), increased the initially low level of attention in ED-Low animals; the highest selectivity was observed at a dose of 3 mg/kg. Radioligand analysis showed that at this dose, the drug changed density (Bmax) of D2 and GABAB receptors as markers in the pre-frontal cortex of the ED-Low subpopulation to Bmax values observed in the ED-High subpopulation. In the prefrontal cortex of the ED-Low rodents treated with GIZh-290 in dose of 3 mg/kg, there was a normalization of tissue concentrations of both dopamine itself (DA) and its intra- and extracellular metabolites (DOPA/DA and HVA/DA). The obtained results indicate the effectiveness of the studied drug for pharmacotherapy of attention deficit in experimental modeling and impact on potential molecular targets identified in the study.

[Influence of pantogam and atomoxetine on attention stability and distribution of dopamine D2 and GABAB receptors in the attention deficit mouse model]. / Vliianie pantogama i atomoksetina na ustoichivost' vnimaniia i raspredelenie dofaminovykh D2 i GAMKV-retseptorov u myshei s model'iu defitsita vnimaniia.

The closed enriched cross maze test was employed as a new experimental model of the attention deficit disorder (ADD) for evaluation of the behavioral and neurochemical effects of the nootropic drug pantogam (100 mg/kg, intraperitoneally) and atomoxetine hydrochloride (3 mg/kg, intraperitoneally) administered subchronically to CD-1 outbred mice. Two subpopulations of rodents differed spontaneously in attention to enriched compartments (ED-Low and ED-High), were estimated on the basis of time spent by the mice in the empty or enriched compartments. The ED-Low and ED-High mice insignificantly differed in parameters associated with anxiety, exploratory efficacy and motor activity. Subchronic administration of both drugs in selected doses produced corrective effect on animal behavior seen as a selective increase in the ED-ratio values in the ED-Low subpopulation. Differences in the distribution of dopamine D2 and GABAB receptors (Bmax) between placebo-treated ED-Low and ED-High mice were found in the prefrontal cortex using the radioligand binding method. The neuroreceptor effects of atomoxetine were seen in prefrontal cortex of ED-Low mice as decrease in the Bmax values of D2 receptors by 14%. Pantogam in the prefrontal cortex of ED-Low subpopulation showed a decrease in the Bmax values of D2 receptors by 22% and an increase for GABAB receptors by 44%. Therefore, subchronic administration of pantogam had a positive corrective effect on the behavior parameters and the density of the studied receptor subtypes in animals with severe attention deficit.

A Multi-strain Potential Probiotic Formulation of GABA-Producing Lactobacillus plantarum 90sk and Bifidobacterium adolescentis 150 with Antidepressant Effects.

Today, a number of studies conclusively show that certain bacterial strains, mainly from the genera Lactobacillus and Bifidobacterium, influence the functioning of the central nervous system, leading to changes in beahvior, nociception and the cognitive abilities of humans and animals. Such strains serve as the basis for developing probiotics with a curative potential for the central nervous system - psychobioitcs. However, the question of how to find such strains and which criteria to use for their selection remains unanswered. Some compounds produced by bacteria, such as gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter of the central nervous system, are potential mediators between bacterial cells and the host. Previously, we established that some species of Lactobacillus and Bifidobacterium are capable of producing GABA. We presumed that GABA-producing Lactobacillus and Bifidobacterium strains are great candidates to use as psychobiotics. Therefore, we selected the strains Lactobacillus plantarum 90sk and Bifidobacterium adolescentis 150 as efficient GABA producers. The goal of this work was to assess the probiotic properties of the selected strains as well as their antidepressive effects in mice. We established that the ingestion of the probiotic composition based on the selected strains by BALB/c mice for 2 weeks reduced depressive-like behavior in the forced swimming test; the effect was similar to that of fluoxetine.

[COMPARISON OF PHARMACOLOGICAL EFFECTS OF HEPTAPEPTIDE SELANK AFTER INTRANASAL AND INTRAPERITONEAL ADMINISTRATION TO BALB/c AND C57BL/6 MICE.]

Pharmacological effects of intraperitoneal (i.p.) and intranasal (i.n.) administration of heptapeptide selank (300 µg/kg/day for 5 days), known to possess anxiolytic and nootropic properties, were compared by studying the elevated-plus-maze behavior of inbred BALB/c and C57BL/6 mice and measuring the binding of markers to NMDA and GABA receptors of brain. The anxiolytic and nootropic efficiency of selank administered via both routes was observed only in BALB/c mice, which were characterized by initially reduced exploratory activity and higher levels of anxiety as compared to C57BL/6 mice. In BALB/c mice, i.p. selank increased the number of [G-(3)H]SR 95531 binding sites with GABA-receptors in the frontal cortex by 38%, without change in binding to NMDA receptors in the hippocampus. On the contrary, i.n. selank led to an increase in the density of [G-(3)H]MK-801 binding sites by 23% with no effect on GABA receptors. It is suggested that the differences in pharmacological spectra observed for the two routes of selank administration are determined by specific features of drug pharmacokinetics and biotransformation as well as by the dynamics of formation of the anxiolytic and nootropic effects of selank.

[GABA-ergic mechanism of cerebrovascular and antiischemic effects of docosahexaenoic acid].

In experiments on rats, measurements of the local blood flow in the cortex of cerebrum with the aid of a laser Doppler flow meter showed that docosahexaenoic acid (DHA) enhanced the local cerebral circulation in animals with global transient cerebral ischemia, while not influencing that in intact animals. This vasodilatory effect of DHA in ischemized rats is blocked by bicuculline (specific GABA(A) receptor blocker), which is indicative of a GABA-ergic mechanisms of the vascular tone regulation. The results of radioligand binding assay in vitro showed the possibility of direct DHA interaction with cerebrovascular GABA(A) receptors.

[Experimental study of dicholine succinate pharmacokinetics].

We have conducted for the first time an experimental study of pharmacokinetics of dicholine succinate (DCS) for different ways of its administration in rats The quantitative evaluation of DCS and its metabolites was performed by the radioactive isotope technique. Various parameters of DCS pharmacokinetics were estimated, including the dose dependence of drug content in the blood plasma, total bioavailability, distribution kinetics, and the main ways of DCS excretion.

[The dynamics of behavioral and neuroreceptor effects after acute and long-term noopept administration in C57BL/6 and BALB/c mice].

The effect of acute, 7-fold and 14-fold noopept (1 mg/kg/day) administration on the dynamics of anxiolitic and nootropic behavioral effects in cross-maze, as well as their correlations with NMDA- and BDZ-receptor density was studied in inbred mice strains, differing in exploratory and emotional status--C57BL/6 and BALB/c. The dipeptide failed to affect the anxiety and exploration activity in C57BL/6 mice at each of 3 steps of experimental session. In this strain the B(max) values of [3H]-MK-801 and [3H]-Flunitrazepam binding changed only after single administration. In respect to BALB/c mice noopept induced both the anxiolitic and nootropic effects reaching their maximum on 7th day. In BALB/c strain the dynamics of hippocampal NMDA-receptor binding corresponds to the dynamics of exploratory efficacy whereas the dynamics of BDZ-receptors in prefrontal cortex was reciprocally to dynamics of anxiety level.

[The influence of piracetam on behavior and brain receptors in C57BL/6 and BALB/c mice: nootropic and anxiolytic effects].

The influence of acute and long-term piracetam administration on the dynamics of rapid (non-specific, anxiolytic) and slow (specific, nootropic) behavioral drug effects, as well as on their interrelation with NMDA- and BDZ-receptors was studied in inbred mice strains differing in cognitive and emotional status--C57BL/6 and BALB/c. The BALB/c strain contained 17% less [3H]-flunitrazepam binding sites in frontal cortex and 22% less [3H]-MK801 binding sites in hippocampus as compared to those in C57BL/6 mice. Based on these data, BALB/c strain was used as a model of psychopathology, combining increased anxiety and cognitive deficit. Under the action of single, 7-fold, and 14-fold piracetam i.p. injections (200 mg/kg body weight, daily), a fast increase in NMDA-receptor density and slow escalation of the specific nootropic effect was observed in BALB/c mice. Non-specific anxiolytic effects in these mice increased for the first 1 - 7 days without any changes in BDZ-binding and then decreased to initial values accompanied by decrement of brain receptor concentration. Thus, in BALB/c mice, a slowly manifested specific nootropic action of piracetam develops, following an increase in NMDA receptor density, whereas the non-specific anxiolytic effect precedes the fast-paced changes in BDZ-binding site density.

[Effects of nootropic drugs on behavior of BALB/c and C57BL/6 mice in the exploratory cross-maze test].

Exploratory behavior, locomotor activity, and anxiety in inbred mice of C57BL/6 and BALB/c strains subchronically treated with placebo or various types of nootropic (cognition enhancing) drugs (piracetam, phenotropil, noopept, semax, pantogam, nooglutil) have been evaluated using the exploratory cross-maze test. It was found that BALB/c mice in comparison to C57BL/6 mice are characterized by greater anxiety and lower efficiency of exploratory behavior in the previously unfamiliar environment. All tested drugs clearly improved the exploratory behavior in BALB/c mice only. In BALB/c mice, piracetam, phenotropil, noopept, and semax also reduced anxiety, while phenotropil additionally increased locomotor activity. Thus, the nootropic drugs displayed clear positive modulation of spontaneous orientation in the mice strain with initially low exploratory efficiency (BALB/c) in the cross-maze test. Some drugs (pantogam, nooglutil) exhibited only nootropic properties, while the other drugs exhibited both nootropic effects on the exploratory activity and produced modulation of the anxiety level (piracetam, fenotropil, noopept, semax) and locomotor activity (fenotropil).

Blood-brain barrier unlocked.

The brain is protected by a physiological blood-brain barrier (BBB) against toxins and some metabolites circulating in the blood. At the same time, the BBB limits penetration into the brain of many neuroactive drugs. Efficient ways to increase BBB permeability for delivery of drugs of different chemical nature into the brain are unknown. This work deals with delivery into the brain of 10(-2) M dopamine, a substance that does not penetrate the BBB under normal circumstances. It was studied in two independent experiments: (i) penetration of (3)H-labeled dopamine from its mixture with 10(-5) M H2O2 into hypothalamus and striatum structures of intact rat brain, and (ii) effect of unlabeled dopamine from a mixture with H(2)O(2) on the rat motor activity in a haloperidol catalepsy model. It was shown that (i) at the third minute after nasal application of the dopamine + H(2)O(2) mixture, the dopamine level increases 45-fold in the hypothalamus and almost 30-fold in the striatum and (ii) motility of animals in the catalepsy haloperidol model is recovered 90 sec after intranasal introduction of dopamine. No such effects were observed after replacement of H(2)O(2) by 0.9% NaCl solution. Thus, it was shown on the example of dopamine that its introduction into the nasal cavity simultaneously with H(2)O(2) provides for rapid delivery of the drug into the brain. These results expand our knowledge concerning the biological role of exoROS in modulating BBB permeability and may contribute to the development of a new therapeutic strategy for neurological diseases.

[Pantogam and pantogam active: qualitative and quantitative features of the interaction with neurotransmitter receptors in vitro].

We conducted a comparative study on the effect of active compounds of pantogam and pantogam active (calcium D(R)-homopantothenate and calcium DL(RS)-homopantothenate) and its L(S)-isomer on the receptors of main brain neuromediators in rats using in vitro radioligand binding analysis. All three compounds interact with binding sites of specific GABA-A and, in particular, GABA-B receptor ligands. Racemate and S-enantiomer, but not its R-form, competed to a moderate degree for D2-receptor binding sites. In all cases, degrees of interaction with receptors were ranged as follows: S-isomer>racemate>R-isomer. These qualitative and quantitative differences are assumed to contribute to pharmacological activity of both drugs.

Binding of specific ligand by D2- and NMDA-receptors of striatum cells in two rat strains predisposed and resistant to audiogenic seizures.

We studied parameters of specific receptor binding of D2-dopamine receptor ligand [(3)H]-sulpiride and NMDA-receptor ligand [(3)H]-MK-801 on the membranes of striatum cells in Krushinsky-Molodkina rats (predisposed to audiogenic seizures) and strain "0" selected for the absence of audiogenic seizures. No interstrain differences were observed in affinity (K(d)) of both D2- and NMDA-receptors to ligands. At the same time, significant interstrain differences in receptor density (B(max)) were found for both D2-receptors and NMDA-receptors. The reduced number of dopamine and glutamate receptors in the striatum can be associated with neurological peculiarities of Krushinsky-Molodkina rat strain (audiogenic seizures and postictal catalepsy).

[Influence of hemantane and doxycycline on MPTP-evoked behavior violations in C57BL/6 mice].

The effects of anti-parkinsonian drug hemantane [(2-adamantyl)hexamethylenimine] (10 mg/kg, p. o.) and/or antibiotic drug doxycycline (100 mg/kg, p. o.), as well as that of neurotoxin 1-methyl-4-phenyl-1,2,3,4-tetrahydropyridine (MPTP) (4 x 20 mg/kg, i. p.) were studied in elevated plus maze test on C57BL/6 mice. On second day after injection, MPTP decreased the locomot or activity in comparison to saline. Acute administration of hemantane or doxycycline failed to influence locomotion in mice, while their combination normalized motor activity. The results obtained confirm the role of inflammatory processes in parkinsonism and suggest expediency of combined pharmacotherapy of neurodegenerative diseases.

[Studying specific effects of nootropic drugs on glutamate receptors in the rat brain].

The influence of nootropic drugs of different groups (piracetam, phenotropil, nooglutil, noopept, semax, meclofenoxate, pantocalcine, and dimebon) on the binding of the corresponding ligands to AMPA, NMDA, and mGlu receptors of rat brain has been studied by the method of radio-ligand binding in vitro. It is established that nooglutil exhibits pharmacologically significant competition with a selective agonist of AMPA receptors ([G-3H]Ro 48-8587) for the receptor binding sites (with IC50 = 6.4 +/- 0.2 microM), while the competition of noopept for these receptor binding sites was lower by an order of magnitude (IC50 = 80 +/- 5.6 microM). The heptapeptide drug semax was moderately competitive with [G-3H]LY 354740 for mGlu receptor sites (IC50 = 33 +/- 2.4 microM). Dimebon moderately influenced the specific binding of the ligand of NMDA receptor channel ([G-3H]MK-801) at IC50 = 59 +/- 3.6 microM. Nootropic drugs of the pyrrolidone group (piracetam, phenotropil) as well as meclofenoxate, pantocalcine (pantogam) in a broad rage of concentrations (10(-4)-10(-10) M) did not affect the binding of the corresponding ligands to glutamate receptors (IC50 100 pM). Thus, the direct neurochemical investigation was used for the first time to qualitatively characterize the specific binding sites for nooglutil and (to a lower extent) noopept on AMPA receptors, for semax on metabotropic glutamate receptors, and for dimebon on the channel region of NMDA receptors. The results are indicative of a selective action of some nootropes on the glutamate family.

[A comparative study of hemantane and amantadine effects on dopamine transporter expression in brain of normal and MPTP-treated C57BL/6 mice].

The effects of acute and subchronic administration of antiparkinsonian drugs hemantane and amantadine on dopamine transporter (DAT) content in the brain of normal and MPTP-treated mice have been studied. MPTP treatment (30 mg/kg, daily for 2 days, i.p.) led to an insignificant decrease of the DAT level in striatum, while not influencing the DAT content in the frontal cortex of mice. The acute administration of hemantane (20 mg/kg, i.p.) failed to influence the DAT levels in the tested structures of mice brain, while amantadine (13.9 mg/kg, i.p) decreased the DAT level but only in striatum. The acute administration of a drug (hemantane or amantadine) simultaneously with MPTP toxin reduced the DAT levels in striatum but did change the DAT concentration in the frontal cortex. On the contrary, the subchronic injection of hemantane alone (7 x 20 mg/kg, i.p.) and in combination with the toxin increased the DAT levels in the brain structures, while amantadine (7 x 13.9 mg/kg, i.p.) led to a pronounced increase of DAT concentration only in the striatum. Thus, both similar and dissimilar trends in the neurochemical effects of hemantane and amantadine have been experimentally revealed.

Study of anti-inflammatory effects of GB-115, a glycine-containing retropeptide cholecystokinin analog.

Anti-inflammatory effects of GB-115 compound (N-phenylhexanoyl-glycyl-L-tryptophan amide) injected intraperitoneally in doses of 0.1, 1, and 10 mg/kg were demonstrated on the model of ConA- and carrageenan-induced inflammation. Intraperitoneal injection of GB-115 in a dose of 1 mg/kg to C57Bl/6 female mice with experimental autoimmune encephalomyelitis significantly alleviated the pathological symptoms, improved spontaneous locomotor activity, promoted recovery of thymus weight, and reduced edema and neutrophil infiltration of the perivascular space of the brain tissue. Intraperitoneal injection of GB-115 in a dose of 1 mg/kg suppressed generation of active oxygen forms by neutrophils in the chemiluminescence test.

[Simultaneous AMPA receptor potentiation and NMDA receptor blockade as strategy for creating effective stimulants for cognitive functions].

New compounds representing derivatives of acyclic isothioureas have been synthesized, which are capable of simultaneously activating AMPA receptors and blocking NMDA receptors. In order to produce cognitive-stimulating effect, of principal importance is the pathway of NMDA receptor blockade produced by the drug. Positive influence is due to the blockade of NMDA receptors either by mechanism of rapid dissociation of intrachannel site or by inhibition of NR2B subunit of NMDA receptor. Substances that only potentiate AMPA receptor currents or only block NMDA receptors have less pronounced effect on memory than substances with ability to simultaneously potentiate AMPA receptor currents and block NMDA receptor currents. Based on these results, it is concluded that the simultaneous potentiation of AMPA receptors and blockade of NMDA receptors may be a new approach to the stimulation of cognitive functions.

[Role of the brain dopaminergic and serotoninergic systems in psychopharmacological effects of ladasten and sydnocarb].

The influence of ladasten and sydnocarb on dopamine and serotonin receptors and the biosynthesis and re-uptake of dopamine and serotonin has been studied. It is established that both drugs do not produce any direct effects on dopamine D1, D2, and D3 receptors in rat striatum as well as on serotonin 5-HT1A and 5-HT2A receptors in rat frontal cortex in vitro. Ladasten in a single dose of 50 mg/kg (i.p.) stimulated ex vivo dopamine biosynthesis and release in striatum, without any influence on serotonin formation neither in striatum nor in frontal cortex. On the contrary, sydnocarb (17.5 mg/kg, i.p.) decreased the level of serotonin synthesis both in striatum and frontal cortex, while not affecting the biosynthesis of dopamine. Both ladasten and sydnocarb inhibited the active transport of dopamine in rat striatal synaptosomes at IC50 = 3.56 microM and 28.66 nM, respectively, but failed to influence the serotonin re-uptake in rat frontal cortex.

[Effects of subchronic hemantane administration on dopamine and serotonin receptors in intact and MPP+-treated rat brain ex vivo].

The influence of the new antiparkinsonian drug hemantane on D1 receptors in striatum, 5-HT1A receptors in hippocampus, and 5-HT2A receptors in frontal cortex of intact and MPP+-treated (3 microg/0.6 ml dist., intranigral) rats was studied. Hemantane (20 mg/kg, i.p.) was administrated subchronically for 7 days (beginning a day after MPP+ injection). A modulatory effect of hemantane on D1, 5-HT1A and 5-HT2A receptors was revealed. It was found that hemantane increased the binding site density (Bmax) of D1 and 5-HT1A receptors and decreased the binding site density of 5-HT2A receptors without changing the affinity (Kd) to the selective ligands. These results demonstrate that subchronic administration of hemantane leads to the functional rearrangement of dopamine and serotonin receptors in the brain of both intact and MPP+-treated rats.

[Ligands of glutamate and dopamine receptors evenly labeled with hydrogen isotopes].

A reaction of high-temperature solid-phase catalytic isotope exchange (HSCIE) was studied for the preparation of tritium- and deuterium-labeled ligands of glutamate and dopamine receptors. Tritium-labeled (5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclopenten-5,10-imine ([G-(3)H]MK-801) and R(+)-7-hydroxy-N,N-di-n-propyl-2-aminotetraline ([G-(3)H]-7-OH-DPAT) were obtained with a specific activity of 210 and 120 Ci/mol, respectively. The isotopomeric distribution of deuterium-labeled ligands was studied using time-of-flight mass-spectrometer MX 5310 (ESI-o-TOF) with electrospray and orthogonal ion injection. Mean deuterium incorporation per ligand molecule was 11.09 and 3.21 atoms for [G-(2)H]MK-801 and [G-(2)H]-7-OH-DPAT, respectively. The isotope label was shown to be distributed all over the ligand molecule. The radioreceptor binding of tritium-labeled ligands [G-(3)H]MK-801 and [G-(3)H]-7-OH-DPAT was analyzed using the brain structure of Vistar rats. It was demonstrated that [G-(3)H]MK-801 specifically binds to hippocampus membranes with K(d) 8.3 +/- 1.4 nM, B(max) being 3345 +/- 300 fmol/mg protein. The [G-(3)H]-7-OH-DPAT ligand specifically binds to rat striatum membranes with K(d) 10.01 +/- 0.91 nM and B(max) 125 +/- 4.5 fmol/mg protein. It was concluded that the HSCIE reaction can be used for the preparation of highly tritium-labeled (+)-MK-801 and 7-OH-DPAT with retention of their physiological activities.