The Effect of Ionizing Radiation on Cognitive Functions in Mouse Models of Alzheimer's Disease.

The present study demonstrates the effect of combined ionizing radiation (γ rays, 0.24 Gy, 661.7 keV, whole body and 12C, 0.18 Gy, 450 MeV, head region) on the behavior of animals in mouse transgenic models of Alzheimer's disease. Significant improvement of spatial learning and stimulation of locomotor and exploratory behavior were observed in wild-type mice after irradiation. However, an anxiolytic effect and stimulation of locomotor and exploratory behavior were revealed in irradiated mice with tauopathy. Mice with cerebral amyloidosis also exhibited improved learning in the odor recognition test. No negative effects of irradiation were detected.

[Dimebon correction of changes in phospholipid composition induced by tumor necrosis factor-alpha in experement]. / Korrektsiia dimebonom narushenii sostava fosfolipidov v strukturakh mozga, vyzvannykh faktorom nekroza opukholi α v éksperimente.

AIM: To investigate the ability of the neuroprotector dimebon to prevent alterations in brain lipid metabolism caused byTNF-α. MATERIAL AND METHODS: The ability of dimebon (2,8-Dimethyl-5-[2-(6-methyl-3-pyridinyl)ethyl]-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole hydrochloride) to prevent alterations in brain lipid metabolism caused byTNF-α was studied in 65 male mice (20+2g weight). TNF-α (10 mkg/mouse), dimebon (0.2 mg/kg) and their combination were injected intraperitoneally. Thirty min, 2, 4 and 24 h after injection, lipid level alterations in total fractions and molecular species of phospholipids (phosphatidylcholine, lysophosphatidylcholine, sphingomyelin and phosphatidylethanolamine) were measured with mass-spectrometry in the hippocampus, cortex and cerebellum. RESULTS AND CONCLUSION: After injection of TNF-α into mice, there are significant changes in the level of all tested phospholipids. Dimebon at a dose of 0.2 mg/kg alone does not cause any changes in the content of all tested phospholipids, but injected together with TNF-α prevents cytokine induced alterations in the lipid content. The selectivity of TNF-α and dimebon influence on certain molecular species of various phospholipids in different parts of mouse brain is found. The presented data suggest protective properties of dimebon preventing the development of proinflammatory syndrome induced by TNF-α in the animal brain.

[Tumor necrosis faсtor-alpha - potential target for neuroprotector dimebon]. / Faktor nekroza opukholei-al'fa - potentsial'naia mishen' dlia neiroprotektora dimebona.

Dimebon (Dimebolin) is an antihistamine drug which has been used in Russia since 1983. Recently Dimebolin has attracted renewed interest after being shown to have positive effects on persons suffering from Alzheimer's disease. Animal studies have shown that dimebon acts through multiple mechanisms, both blocking the action of neurotoxic beta-amyloid peptides and inhibiting L-type calcium channels, modulating the action of AMPA and NMDA glutamate receptors. Our experiments with cell culture L929 and mice have shown that dimebon may exert its neuroprotective effect by blocking cytotoxic signals induced by proinflammatory cytokines such as TNF-a which are believed to play a central role in Alzheimer's disease. Dimebon (10 mg/ml) protected mouse fibroblasts L929 against the toxic action of TNF-a. Our study included 65 male mice. TNF-a (10 mg per mouse), dimebon (0,2 mg/kg) and their combination were injected intraperitonealy. Changes in the level of molecular species of sphingomyelin and galactosyl ceramide in hippocampus, cerebellum and cerebral cortex within 30 min, 2 h, 4 h, and 24 h after injection were detected by chromato-mass-spectrometry. Maximal changes in sphingomyelin and galactosyl ceramides contents of different molecular species after single TNF-a administration were found in the hippocampus, and were less expressed in the cerebral cortex and cerebellum after 24 h. Dimebon itself did not induce changes in the sphingolipid spectrum in brain sections, but protected them against disorders induced by TNF-a in the brain. Modern strategies in the search of new therapeutic approaches are based on the multitarget properties of new drugs. According to our results TNF-a may serve as a new target for dimebon.

Glutamate release and uptake processes are altered in a new mouse model of amyotrophic lateral sclerosis.

In this paper, we showed that in the cortex of mice expressing an abberant form of FUS protein that model amyotrophic lateral sclerosis (ALS), the processes of KCl-induced and basal [(3)H]glutamate release and uptake are altered at the presymptomatic stage as compared to the non-transgenic littermates. The change in these three parameters in transgenic animals causes excitotoxicity, which, in turn, may lead to massive loss of motor neurons and the onset of ALS symptoms.

[A mice model of amyotrophic lateral sclerosis expressing mutant human FUS protein].

UNLABELLED: BACKGROUND AND ОBJECTIVE: Loss of conformation and function of sufficient number of proteins with high aggregation capacity plays an important role in the pathogenesis of many neurodegenerative disorders (NDD). Due to a recent discovery of new array of proteins with the capacity to form aggregates of nonamyloid type, new NDD models as well as a new level of understanding in vivo models which are already exist is needed. DNA/RN A binding proteins - FUS and TDP-43 play a crucial role in the pathogenesis of some forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. The objective of the study was to develop a new ALS transgenic model. MATERIAL AND METHODS: In cell culture experiments, we studied mutant FUS proteins capable to form intracellular deposits morphologically similar to those observed in the autopsy material of ALS patients. RESULTS AND CONCLUSION: We created a transgenic mice line, in which a pathogenic form of human FUS protein was expressed in the nervous system. That led to the aggregation of FUS protein in spinal cord and motor neurons with the following degeneration and development of a phenotype, similar to the human ALS disease phenotype, in young grown-up animals. This neurodegenerative phenotype corresponds to a great number of clinical manifestations of human ALS and is an adequate transgenic model of the disease.

[Study into molecular targets of a neuroprotective compound dimebon using a transgenic mice line].

In the present study we have used a transgenic mice overexpressing an amyloidogenic protein, gamma-synuclein, in the nervous system to address the effect of dimebon on proteinopathy progression. Neuroprotective effect of chronic dimebon administration in these mice at organismal level was confirmed by the increased lifespan. Using histological and biochemical approaches we have demonstrated that dimebon reduced the number of amyloid inclusions in spinal cord of transgenic animals and decreased the content of ubiquitinated proteins in detergent-insoluble fractions. These effects are likely to occur at the level of aggregated protein species, since transgene expression was not altered. Thus, pathological protein aggregation serves as one of dimebon targets in neurodegeneration.

Effect of somatostatin on presynaptic and postsynaptic glutamate receptors and postsynaptic GABA receptors in the neurons of rat brain.

We studied the effect of somatostatin on presinaptic NMDA receptors and postsinaptic GABA, NMDA, and AMPA receptors in rat brain. It was shown that somatostatin inhibits NMDA-induced (45)Ca(2+) uptake into synaptosomes isolated from rat brain cortex (IC50=2.8×10(-11) M). Somatostatin potentiates AMPA receptors and inhibits hippocampal NMDA receptors in the entire range of examined concentrations (10(-14)-10(-7) M); it also potentiates or inhibits GABA receptor currents in a concentration-dependent manner. Our results suggest that somatostatin modulates the function of ionotropic glutamate and GABA receptors and is involved in cognitive and neurodegenerative processes in the mammalian brain.

The effects of estrogens on learning in rats with chronic brain cholinergic deficiency in a Morris water test. Identification of the "passive swimming" component.

Chronic decreases in brain cholinergic functions due to intraventricular administration of the neurotoxin AF64A were accompanied by increases in the latent period of locating an invisible platform during training of rats in a Morris water test, as compared with control sham-operated animals. Recordings of the animals' movement trajectories using a video camera along with an original computer program (Behavioral Vision) showed that administration of 17beta-estradiol and its synthetic analog J-861 (0.2 mg/kg p.o. daily for seven days before and 10 days after single intraventricular injections of AF64A) improved learning. The directivity of platform search trajectories was assessed quantitatively using a new parameter--trajectory straightness. Introduction of the "passive swimming" parameter allowed periods of immobility in water to be identified within the total latent period in animals after administration of AF64A; 17beta-estradiol but not J-861 "eliminated" these periods. The new parameters (especially trajectory straightness) allowed the ability to learn to be discriminated from decreases in mobility, including mobility losses due to study agents, in the Morris water test.

[2-Amino-2-thiazoline derivatives--a novel chemotype possessing muscarinomimetic effect]. / Proizvodnye 2-amino-2-tiazolina--novyi khemotip, obladaiushchii muskarinopodobnym deistviem.

Derivatives of 2-amino-2-thiazoline exhibit muscarinomimetic properties in model experiments with isolated rat ileum. The activity of compounds strongly depends on the nature of substituents in 5-position of thiazoline ring. The most active spasmogenic compound is 5-iodomethyl-2-amino-2-thiazoline hydroiodide (EC50 = 13 +/- 2 microM). Its effect is very similar to activity of cholinergic agent pilocarpine (EC50 = 14 +/- 4 microM), but "intrinsic activity" parameter a (alpha = 0.87 +/- 0.12) of 5-iodomethyl-2-amino-2-thiazoline was more significant. Ileum contractions induced by this compounds were inhibited by atropine. Derivatives of 2-amino-2-thiazoline (like pilocarpine) were not demonstrated nicotinomimetic properties. These compounds demonstrate very weak anti-AChE activity. For 5-iodomethyl-2-amino-2-thiazoline hydroiodide the IC50 value is 0.39 +/- 0.09 mM.

Content of autoantibodies to bradykinin and beta-amyloid(1-42) as a criterion for biochemical differences between Alzheimer's dementias.

We measured serum content of autoantibodies to beta-amyloid protein Abeta(1-42), its neurotoxic fragment Abeta(25-35), vasopressin, bradykinin, thrombin, antithrombin III, alpha(2)-macroglobulin, and angiotensin II in patients with various forms of Alzheimer's dementias, including presenile and senile dementias of the Alzheimer type. The ratio of antibradykinin and anti-Abeta(1-42) autoantibody contents differed by 39% in these patients. Our results can be used for the development of a new biochemical method for differential diagnostics of dementias of the Alzheimer type.

[Effects of estrogens on learning of rats with chronic brain cholinergic deficit in Morris water maze]. / Vliianie éstrogenov na obuchenie krys s khronicheskim kholinergicheskim defitsitov v mozge v vodnom teste Morrisa. Vydelenie komponenta "passivnogo plavaniia".

A chronic deprivation of brain cholinergic functions in rats caused by intracerebroventricular injection of neurotoxin AF64A increases the escape latency in Morris water maze test as compared to control sham-operated animals. Measurements and analysis of rat movement tracks using an original computerized "Behavioral Vision" system revealed the ability of 17 beta-Estradiol and its synthetic isomer J-861 (both administered daily in per os dose 0.2 mg/kg during 7 days before and 10 days after a single intracerebroventricular injection of AF64A) to improve learning of the animals. Directivity of search trajectories was estimated by a novel index of track straightness. The introduction of an index of "passive swimming" made it possible to reveal episodes of immobility in water-maze behavior of AF64A-injected animals. Unlike J-861, 17 beta-Estradiol almost completely eliminated these episodes. The newly developed indices (especially straightness) seem to be very useful in differentiating learning ability of rats from a decrease in their mobility in the Morris water-maze test, in particular, in case of the estrogens under study.

Effects of 17 beta-estradiol and its isomer 17 alpha-estradiol on learning in rats with chronic cholinergic deficiency in the brain.

It was shown for the first time that estrogens 17 beta- and 17 alpha-estradiols compensate impaired cognitive functions in rats with partial chronic deprivation of cholinergic functions in the central nervous system induced by intracerebral administration of selective cholinergic neurotoxin AF64A. 17 beta-Estradiol produced strong dose-dependent changes in the weights of hormone-sensitive endocrine glands, while 17 alpha-estradiol did not affect the weight of the gonads and slightly influenced (in high concentration) the weights of the adrenal glands and thymus. The positive effects of exogenous 17 beta- and 17 alpha-estradiols on cognitive functions are due to their antioxidant properties, rather than due to specific action on hormone-sensitive endocrine glands.