Journal of Evolutionary Biochemistry and Physiology

Hibernation is the ability of a number of animals to hibernate for a long time, is a natural hypometabolic condition that allows hibernating animals to tolerate such adverse environmental factors as a decrease in temperature, lack of food and water. The ability to hibernate is a consequence of adaptations accumulated during evolution at various physiological levels, among which the key is molecular adaptation to hypoxia, which eliminates not only the negative effect of oxygen deficiency on cells, but also the danger of oxidative stress (OS) induced by hypoxia. This aspect of hibernation is of great medical importance, as understanding the mechanisms underlying the adaptation of hibernators to hypoxia and OS can help solve a number of important problems in the prevention of posthypoxic complications in people with chronic neurodegenerative and heart diseases. The molecular basis of adaptation to hypoxia in hibernators is the presence of an effective antioxidant system (AOS) and regulatory mechanisms that ensure the extreme plasticity of mitochondria (intracellular ROS inducers), especially pronounced when animals come out of hibernation. During this period, the rate of oxygen consumption increases in cells and the antioxidant system (AOS) is activated, including low molecular weight (glutathione (GSH)) and enzyme (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GP), glutathione-S-transferase (GST) and glutathione reductase (GR) components. The thioredoxin system and vitamins (A, C, and E) are also involved in the process of protecting tissues from oxygen free radicals in hibernators. Despite the close interest in the problem of regulating ROS production in the mitochondria of hibernators, the question of the participation of antioxidant systems and its individual components in the detoxification of excess ROS products during various periods of natural hibernation has not been sufficiently studied. The question of the possibility of extrapolating the data obtained on model animals to humans remains important. This review summarizes and analyzes the latest data on advances in the study of mitochondria and antioxidant protection during hibernation in mammals, mainly ground squirrels, which are generally accepted experimental models of hibernation.

This article was written to commemorate the 100th anniversary of Michel Jouvet (1925–2017), a leading French neurophysiologist and somnologist. It briefly examines Jouvet’s biography, as well as the history of the discovery of paradoxical sleep, its phylogeny and ontogeny, as well as the study of the neural and neurotransmitter systems of the brain involved in regulating the sleep-wake cycle.

Alzheimer's disease (AD) is one of the most common forms of dementia worldwide. A key histopathological feature of AD is the extracellular deposition of beta-amyloid plaques. In AD patients, the development of cognitive impairment is more closely associated with synaptic loss. In this regard, studying the mechanisms behind the synaptic dysfunction and identifying ways of AD correction is relevant. It should be noted, that synaptophysin is one of the main markers of synapses, which is localized in the membranes of presynaptic vesicles. The aim of the study is to morphologically assess the distribution of synaptophysin protein in brain structures of 5xFAD transgenic mice in the presence of amyloid accumulations. Transgenic line of 5xFAD mice (n = 3) was used in the present study. An immunohistochemical staining to synaptophysin with additional alcian blue colouring was carried out to identify synaptic terminals and amyloid clusters in the cortex and hippocampal formation. Clusters of intensely stained synaptophysin-immunopositive grains surrounding the amyloid plaques were detected in the hippocampal formation and cortex. The most pronounced amyloidosis with abnormal distribution of synaptophysin-immunopositive structures has been observed in the subiculum, CA1 region of the hippocampus and the inner (ganglionic and polymorphic) layers of the cortex by morphometric analysis. A positive linear dependence between the area of synaptophysin-immunopositive grains and the size of amyloid plaques in different regions of the hippocampal formation and cortex has been established by regression analyses. The intense accumulation of synaptophysin-immunopositive grains surrounding the amyloid plaques suggest a functional dependence between the progression of amyloid pathology and synaptic dysfunction.

Lead (Pb²⁺) is a common and environmentally hazardous element. Lead poses a significant health risk because it can mimic the effects of metal ions such as zinc and calcium, which are involved in cellular signaling and metabolism. Available data re the effects of Pb²⁺ on myocardial and vascular function are contradictory. Moreover, the effect of Pb²⁺ on store-operated calcium entry (SOCE) in cardiovascular cells has not been studied. Therefore, the aim of this study was to investigate the short-term effects of Pb²⁺ on spontaneous contractility of cardiac muscle and blood vessels in situ and determine its toxic effects on SOCE. We used isolated atrial and aortic muscle preparations of male frogs, Rana ridibunda. Pb²⁺ at concentrations of 0.1 and 0.4 mM had a significant negative inotropic effect, and increased stiffness, and reduced the amplitude of KCl-induced aortic contraction. Pb²⁺ reversibly blocked SOCE in aortic smooth muscle cells, which may exacerbate its toxic effects on organisms.

Type 1 diabetes mellitus (T1DM) is associated with a high risk of cardiovascular complications, including diabetic cardiomyopathy. However, early markers of these disorders are not sufficiently studied. The relevance of this work is driven by the need to identify predictors of cardiac complications in preclinical models. The aim of the study was to assess the levels of blood electrolytes (Na⁺, K⁺, Ca²⁺, Cl^-, glucose, lactate) and measure electrocardiogram (ECG) parameters in male Wistar rats with prediabetes and T1DM induced by a streptozotocin injection (35 mg/kg, i.p.). A prospective comparative study was conducted over 60 days on three groups: control (C-group, n = 15), prediabetes (PDM-group, n = 15), and T1DM (DM-group, n = 8). Glucose levels were determined using a glucometer. ECG was recorded on day 56 of the experiment using a “Poli-Spectr-8/V” electrocardiograph. Electrolyte levels were measured on day 60 using an Eros® Reader analyzer. The following statistically significant differences (p < 0.05) were observed compared to the C-group. Glucose levels were higher than in the C-group (6.2 mM): 7.7 mM (PDM) and 24.9 mM (DM). In the DM-group, the concentration of Na⁺ (137 ± 4 vs. 143 ± 2 mM in the C-group) and Cl^- (100 ± 3 vs. 105 ± 1 mM in the C-group) was decreased. The ECG of the DM-group was characterized by an increase in QRS and QT intervals, as well as a decrease in heart rate (HR) compared to the C and PDM groups. Furthermore, the area of the T-wave on the ECG of DM-group rats increased compared to the C-group. The obtained data suggest that, at least in part, ECG changes in the early stages of T1DM in rats may be associated with disturbances in blood electrolyte balance. Rats with prediabetes are characterized by a more favorable blood metabolite and electrolyte profile, which is not associated with significant ECG abnormalities.