Learning in rats with differing emotional responsiveness and its relation to brain monoamines

The ability for learning was studied in two groups of Wistar line rats divided by susceptibility to the audiogenic stress-stimulation as compared with the monoamines level in various brain structures. The best ability to learn avoidance reaction in a shuttlebox was shown by animals non-resistant to the stress stimulus as compared with the resistant rats, which correlated positively with the exploratory activity in "the open field". The distinct feature of the animals non-resistant to the stress stimulation consisted in a higher reactivity of the monoamine systems, mainly of the noradrenergic system. This group of animals was also characterized by a higher dopamine content and a lower noradrenaline content in the brain-stem. Decreased activity of the brain dopamine-beta-hydroxylase in animals non-resistant to the stress stimulus, has been suggested.     

A Synthetic Fragment of the Receptor for Glycation End Products and Its Analogue Improve Memory in Transgenic Alzheimer’s Disease Mouse Model

Russian Journal of Bioorganic Chemistry - The membrane receptor for advanced glycation endproducts (RAGE) is involved in the development of a number of pathological conditions, including...     

The State of Glutathione in Animal Blood Plasma in the Development of Experimental Pathology that Simulates Neurodegeneration of the Alzheimer’s Disease Type

The study of glutathione in the blood plasma of NMR1 mice during the development of a pathology that simulates neurodegeneration caused by removal of the olfactory bulbs (bulbectomy) was carried out in comparison with sham-operated (not subjected to the removal of the olfactory bulbs) and control (before surgery) animals. At 1 month after surgery, a twofold increase in the levels of reduced and oxidized glutathione was detected and an increase in the thiol/disulfide ratio in the blood plasma of bulbectomized mice relative to sham-operated animals was observed. A decrease in the thiol/disulfide ratio as a result of depletion of reduced glutathione and accumulation of oxidized glutathione in animal blood plasma was observed during the period from 3 to 12 months, which is a sign of a pathological process. The major disorders related to oxidative stress were revealed during the maximum manifestation of the disease. During this period, a significant decrease in the reducing capacity of cellular redox pairs, such as reduced glutathione/glutathione disulphide was observed.     

White storks Ciconia ciconia eavesdrop on mating calls of moor frogs Rana arvalis

Mating calls of animals are often detected by unintended receivers which use sexual signals to obtain information about the signaller. We investigated whether white storks Ciconia ciconia can eavesdrop mating calls of moor frogs Rana arvalis . White storks are dependent on moor frog abundance in early breeding season. Interspecific eavesdropping by predators is common and well documented in tropical anurans, whereas it is less known in temperate zone. We compared the frequency of approaches of white storks to loudspeakers when frog calls and the song thrush Turdus philomelos songs were simultaneously played back using the later as controls. The loudspeaker broadcasting the calls of male moor frogs clearly attracted white storks at 22 out of 84 nests. The bird songs attracted white storks in only one case. In 19 cases birds left the nest for unknown reasons which were considered as potential foraging movements. The results of this field experiment report a new case of eavesdropping on acoustic signals showing that advertisement calls of temperate moor frogs are an important stimulus for white storks.     

Mitochondrial dysfunction in neocortex and hippocampus of olfactory bulbectomized mice,a model of Alzheimer’s disease

Structural and functional impairments of mitochondria in brain tissues in the pathogenesis of Alzheimer’s disease (AD) cause energy deficiency, increased generation of reactive oxygen species (ROS), and premature neuronal death. However, the causal relations between accumulation of beta-amyloid (Aβ) peptide in mitochondria and mitochondrial dysfunction, as well as molecular mechanisms underlying deleterious effects of both these factors in sporadic AD, the most common form in humans, remain unknown. Here we used olfactory bulbectomized (OBX) mice of NMRI strain as a model for sporadic AD. Five weeks after surgery, the OBX mice developed major behavioral and biochemical features of AD neurodegeneration, including spatial memory loss, increased brain levels of Aβ, and energy deficiency. Mitochondria isolated from the neocortex and hippocampus of OBX mice displayed severe functional impairments, such as low NADH oxidation rate, reduced transmembrane potential, and decreased cytochrome c oxidase (complex IV) activity that correlated with high levels of soluble Aβ1-40. Mitochondria from OBX mice showed increased contents of lipid peroxidation products, indicative of the development of oxidative stress. We found that neurodegeneration caused by olfactory bulbectomy is accompanied by energy metabolism disturbances and oxidative stress in brain mitochondria similar to those occurring in transgenic animals–familial AD models and patients with sporadic AD. Therefore, OBX mice can serve as a valid AD model for investigating the mechanisms of AD neurodegeneration, drug testing, and development of therapeutic strategies for AD treatment.     

The Y-Box Binding Protein 1 Suppresses Alzheimer’s Disease Progression in Two Animal Models

The Y-box binding protein 1 (YB-1) is a member of the family of DNA- and RNA binding proteins. It is involved in a wide variety of DNA/RNA-dependent events including cell proliferation and differentiation, stress response, and malignant cell transformation. Previously, YB-1 was detected in neurons of the neocortex and hippocampus, but its precise role in the brain remains undefined. Here we show that subchronic intranasal injections of recombinant YB-1, as well as its fragment YB-1₁₋₂₁₉, suppress impairment of spatial memory in olfactory bulbectomized (OBX) mice with Alzheimer’s type degeneration and improve learning in transgenic 5XFAD mice used as a model of cerebral amyloidosis. YB-1-treated OBX and 5XFAD mice showed a decreased level of brain β-amyloid. In OBX animals, an improved morphological state of neurons was revealed in the neocortex and hippocampus; in 5XFAD mice, a delay in amyloid plaque progression was observed. Intranasally administered YB-1 penetrated into the brain and could enter neurons. In vitro co-incubation of YB-1 with monomeric β-amyloid (1–42) inhibited formation of β-amyloid fibrils, as confirmed by electron microscopy. This suggests that YB-1 interaction with β-amyloid prevents formation of filaments that are responsible for neurotoxicity and neuronal death. Our data are the first evidence for a potential therapeutic benefit of YB-1 for treatment of Alzheimer’s disease.     

Health status of the stands and the young growth in the native spruce forests at the ural foothills,the upper reaches of the Pechora River

Health status of trees was studied in five types of native spruce forests in the Pechora-Ilych Nature Biosphere Reserve. The study has shown that trees in the old-growth bilberry-spruce and fern-shamrock-spruce forests can be characterized as “healthy”, with damage index varying from 0.03 to 0.5. The haircap-moss spruce forest with damage index 0.7 is categorized as a “weakened stand”. Regeneration was pronounced in all forest types. Young growth (1500 to 4300 stems/ha) is mainly composed of conifers and is classified as “healthy”.     

Monoamines and peptidergic Gomori-positive neurosecretory cells of the paraventricular nucleus of the rat hypothalamus in chronic alcohol consumption

For 6 months the rats were kept on 20 degrees ethanol. Then, the rats could choose whether to drink alcohol (A) or water. The rats formed 2 groups: those preferring A and those preferring water. The control rats were kept on water. The function of hypothalamus monoamine- and peptidergic systems were disturbed following chronic A treatment. Alcohol-preferring, unlike water-preferring rats, have revealed higher hypothalamus levels of serotonin and lower levels of dopamine and noradrenaline, which correlated with changes in fluorescence intensity of hypothalamus noradrenaline structures and were accompanied by remarkable disturbances in nonapeptide neurohormone transport in the paraventricular nucleus region.     

Separation and comparative characteristics of subunits of phenylalanyl-tRNA synthetase from Escherichia coli MRE-600 and Thermus thermophilus HB8

Separation of alpha- and beta-subunits of phenylalanyl-tRNA-synthetases from E. coli MRE-600 and Thermus thermophilus HB8 using FPLC has been carried out for the first time. The separated subunits of both enzymes do not possess any detectable tRNA-amino-acylation activity. It was found that in the case of the E. coli enzyme beta-subunits exist in solution mainly in the monomeric form with negligible formation of beta 2-dimers, while alpha-subunits predominantly form alpha 2-dimers over the same concentration range. In the case of Thermus thermophilus phenylalanyl-tRNA-synthetase, both alpha- and beta-subunits mainly exist in the dimeric form. The putative mechanisms of alpha-subunit aggregation and of subunit association for alpha 2 beta 2-type enzymes are discussed.