Influence of a new derivative of 4-aminobutanoic acid on the level of neuromediatory aminoacids, neuromediators and the state of the rats’ hypocamp in conditions of brain ischemia

The aim: to investigate the effect of a new derivative of 4-aminobutanoic acid (compounds KGM-5) on the level of neurotransmitters and neurotransmitter amino acids and the structural-functional state of the hippocampus of rats with acute cerebrovascular accident (ACVA). Materials and methods. ACVA was reproduced in rats by occlusion of the left carotid artery under anesthesia (sodium thiopental (35 mg/kg) intraperitoneally (i/p). 5 groups of animals were used: intact control (IC, n=6), untreated animals with ACVA (CP, n=13); animals with ACVA (n=14), which were treated for 5 days with KGM-5 at a dose of 30 mg/kg i/p, animals with ACVA (n=13), who received i/p comparison drug “Picamilon” (17 mg/kg). There was a group of pseudo-operated animals (POA, n=8). Withdrawal of animals from the experiment was performed on day 6 after modeling ACVA by painless euthanasia under anesthesia. Histological examinations of CA1 and CA3 zones of the ventral hippocampus were performed with staining of sections with thionine by the method of Nissl and hematoxylin, eosin. In the rat brain, neurotransmitter amino acids and neurotransmitters were identified. Statistical processing was performed using the W-Shapiro-Wills test to verify the normality of the distribution and the nonparametric Mann-Whitney U-test. The accepted significance level is p<0.05. Results. Under the influence of the compound KGM-5 and “Picamilon” in the CA1 zone of the hippocampus, the number of normochromic neurons increased by 20 % and 16.6 %, respectively, hyperchromic pycnomorphic neurons and shadow cells decreased respectively by 5.8; 2.9 times and 6.3; 3.5 times, the index of alteration of neurons decreased by 6 times and 4.8 times, respectively, the area of ​​the perikaryon of these neurons increased by 39.7 % and 77.8 %, respectively, compared with KP (p<0.05). Both studied agents showed a less pronounced normalizing effect on the CA3 area of the hippocampus. The new compound KGM-5 showed a normalizing effect similar to “Picamilon” on the level of neurotransmitter amino acids and neurotransmitters in the brain of rats with ACVA. Conclusions. Therapeutic administration of KGM-5 increases the survival of ventral hippocampal neurons, reducing the relative proportion of irreversibly altered cells, and helps to restore impaired levels of neurotransmitter amino acids and neurotransmitters in the brain of rats with ACVA. The neuroprotective effect of the new compound KGM-5 corresponds to this comparison drug “Picamilon”

Neurotransmitter disturbances in some parts of the rat brain and their correction under chronic and intermittent alcohol intoxication

The pool of key neuromediators and some neurotransmitter amino acids in cerebellum, hypothalamus and midbrain of rats exposed to chronic and different variants of interrupted alcohol intoxication was investigated. The most pronounced changes were recorded in midbrain. Chronic alcohol intoxication caused an increase in the concentrations of tyrosine, dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), noradrenaline, tryptophan, serotonin, GABA and aspartate in this part of the rat brain. Interrupted alcohol intoxication with 4 days interval is accompanied by an increase in the content of tyrosine, and noradrenaline. Interrupted alcohol intoxication with 1 day interval leaded to an increase in the concentrations of tyrosine, DOPAC, noradrenalin, tryptophan, GABA, glycine and aspartate. The amino acids composition “Titacin” had a pronounced normalizing effect in the midbrain under interrupted alcohol intoxication with 1 day interval.

Repellent activity of monoterpenoid esters with neurotransmitter amino acids against yellow fever mosquito, Aedes aegypti

Repellent activity of monoterpenoid esters (1-6) with neurotransmitter amino acids (GABA and glycine) was investigated against Aedes aegypti by using a “cloth-patch” assay and compared to reference standard N,N-diethyl-3-methylbenzamide (DEET). Monoterpenoid esters showed repellent activity with minimum effective dosages (MED) in the range of 0.031-0.469 mg/cm2. The carvacrol ester of GABA (2, MED of 0.031 ± 0.008 mg/cm2) exhibited the highest repellency of six monoterpenoid esters tested in comparison to the standard repellent DEET (MED of 0.009 ± 0.002 mg/cm2); however, the repellent activity of carvacrol-glycine ester (5) decreased 4-fold compared to the carvacrol-GABA derivative (2). The repellent activities of menthol GABA (1, MED= 0.375 ± 0.000 mg/cm2) and glycine ester (4, MED=0.312 ± 0.063 mg/cm2) were similar The guaiacol-glycine ester (6) was 3.75-fold more efficacious than the guaiacol ester of GABA (3). In the present study, we report repellent efficacy of prolonged exposure to GABA and glycine esters of menthol, carvacrol, guaiacol (1-6) as compared to the repellent activities of their monoterpene moieties alone.

Neuroprotective effects of glutamate antibodies on memory impairment induced by proinflamatory S100A9 protein oligomers in aging animals

Цель исследования - изучение эффектов хронического интраназального введения антител к глутамату совместно с полученными in vitro олигомерами провоспалительного белка S100A9 на процесс воспроизведения пространственной памяти, а также на содержание нейромедиаторных аминокислот и биогенных аминов в релевантных структурах мозга - гиппокампе и префронтальной коре у 12-месячных мышей С57Bl/6. Методика. В поведенческих экспериментах у всех животных проводили выработку условного рефлекса пассивного избегания и тестировали воспроизведение памятного следа, после этого в нейрохимическом исследовании в гиппокампе и префронтальной коре методом ВЖХ проводили определение концентрации нейромедиаторных аминокислот и биогенных аминов. Результаты. Показано, что введение белка S100A9 олигомеров индивидуально приводило к нарушению воспроизведения памятного следа, а в сочетании с антителами к глутамату данного эффекта выявлено не было. Обнаружено значительное повышение концентрации глутамата в обеих церебральных структурах стареющих животных при действии S100A9 олигомеров и снижение содержания аминокислоты при совместном введении с антителами к глутамату до нормы. Показано существенное снижение содержания дофамина в гиппокампе и префронтальной коре в условиях влияния S100A9 олигомеров, а также повышение уровня его метаболитов в гиппокампе с нормализацией обмена дофамина в присутствии антелел к глутамату. Заключение. Выявленные антиамнестические эффекты антител к глутамату и нормализация нейрохимического профиля в условиях вызванной центральной токсичностью S100A9 олигомерами могут быть использованы в разработке подходов нейропротективной коррекции в том числе при болезни Альцгеймера. The aim of this study was to investigate effects of chronic intranasal administration of glutamate antibodies with in vitro -generated proinflammatory S100A9 protein oligomers, on spatial memory of 12-month old C57Bl/6 mice. In addition, the brain content of neurotransmitter amino acids and biogenic amines was monitored in memory-relevant brain structures (hippocampus and prefrontal cortex) of these animals. Methods. In behavioral experiments, all animals were conditioned in a passive avoidance reflex test and the memory trace was evaluated. In a simultaneous neurochemical study, HPLC-electrochemical detection analysis was performed to measure concentrations of neurotransmitter amino acids and biogenic amines in the hippocampus and prefrontal cortex. Results. Administration of S100A9 oligomers alone resulted in disruption of the memory trace retrieval whereas their combination with glutamate antibodies abolished this memory disorder. Significant increases in glutamate concentration were observed in both of the cerebral structures of ageing animals in response to S100A9 oligomers alone, and there was a reduction of the amino acid levels when coadministered with glutamate antibodies. S100A9 oligomers also evoked a decrease in hippocampal and prefrontal cortical dopamine and synchronously elevated dopamine metabolite concentrations, both of these actions being normalized by glutamate antibody coadministration. Conclusion. Disclosure of the antiamnesic effects of glutamate antibodies, along with their neurochemical stabilizing activity to S100A9 oligomer neurotoxicity might be utilized in the development of neuroprotective approaches in Alzheimer’s disease.