Zhurnal evoliutsionnoi biokhimii i fiziologii最新文献

The metabolic profile of plasma of white non-linear rats was investigated under normal conditions and after chronic inhalational exposure to low doses of aliphatic hydrocarbons with the number of carbon atoms from 6 to 10. Metabolic profile was determined with combination of gas chromatography-mass spectrometry and high performance, high resolution liquid chromatography-mass spectrometry with subsequent use of chemometrical methods for data treatment and presentation. It was shown that continuous 90-day exposure to a mixture of C₆-C₁₀ saturated hydrocarbons at concentration of 160 ± 20.5 mg/m³ results in various impairments of metabolic processes in liver and kidneys. Exposure to hydrocarbons at doses of 31.4 ± 5.6 mg/m³ and 5.2 ± 1.8 mg/m³ evoked significantly smaller changes. Novel metabolic markers of the toxic effect of low concentrations of C₆-C₁₀ aliphatic hydrocarbons were revealed. The ratio of concentrations of pyrophosphoric and oxalic acids in rat blood plasma was found to be the most sensitive marker called <>. A hypothesis is put forward about the redox balance violation as the leading pathogenetic mechanism of neuropathies and concomitant pathologies associated with hydrocarbon chronic intoxication.

In recent years the identification of regulatory mechanisms of the general adaptation syndrome, manifesting itself as the response of an organism to drastic changes in the environment and leading to emotional stress, acquires a special significance. The control over visceral functions plays a particular role in stress reactions because of emerging threat of violation of neurodynamic balance of sympathetic-para- sympathetic relationships with their most sensitive element - the heart. Quick adaptation to stress helps to restore not only the sympathetic-parasympathetic homeostasis but also the energy metabolism. One of the essential components, activating metabolic processes, is taurine. This paper considers the descending influence of the paraventricular nucleus (PVN) on neuronal reactions of the solitary tract nucleus (NTS), the first linking pathways of visceral sensitivity, the mechanisms of central control over visceral reactions by mathematical model analysis of heart rate variability (MMA HRV) as well as morpho-histochemical changes in brain structures integrating and regulating the visceral sphere (PVN of the hypothalamus and the amygdala) under psycho-emotional stress without and with intraperitoneal injection of taurine (50 mg/kg). Acute and semichronic experiments were conducted on white nonlinear rats under 5-hour- long immobilization psycho-emotional stress. A highly defined centralization of vegetative HRV parame- ters (HR, IVR, INRS) was revealed, these parameters being normalized on days 7 and 14 at the background of taurine injections. The interaction and interdependence of the central regulatory mechanisms of cardiovascular reactions are shown as well as a considerable protective effect of taurine on promoting early restoration of adaptive properties of the central and peripheral segments of visceral sensitivity under development of long-term psycho-emotional stress.

This study is a continuation of our research of phenomenology and mechanisms of motion sickness (MS) and the relation of this phenomenon to features of sleep-wake cycle (SWC) changes. It presents data about the effect of MS on SWC in 30-day-old intact rats and rats exposed previously to prenatal hypoxia on days 13 and 19 of gestation. In all groups of animals MS was shown to reduce significantly the waking time and to increase the time of paradoxical sleep (PS). For the first time it became possible to reveal a connection between hypothalamic mechanisms controlling MS and SWC and to suggest the role of this connection in mechanisms of development of the sopite syndrome which may be the only manifestation of MS in some animals and man. The results obtained demonstrate that hypoxia on day 19 of gestation has a greater damaging effect on the thalamocortical sleep-regulating structures than hypoxia on day 13 when only hypothalamic-hippocampal systems controlling slow-wave sleep were found disturbed. Against this background MS substantially suppresses the activity of the brain excitatory systems which provide wake- fulness maintenance (it appears to be the ascending reticular activating system) and enhances the work of those activating systems that control PS. It is in rats exposed to preliminary hypoxia on day 19 of gesta- tion, where it was possible to show the role of the evolutionary young thalamocortical system in the control of PS.

The conception of hypothalamus as a cerebral structure providing homeostasis of metabolism and temperature in an organism was formed in the 60-70-ies of the XX century (hypothalamus as a metabolic or temperature <>). In the following decades investigations of molecular mechanisms of the genesis of circadian and circannual rhythms expanded our knowledge of hypothalamic functions essentially. According to modern ideas, hypothalamic nuclei play a role as <> for other structures and evoke the genesis of various processes with temporal parameters (such as latency, velocity, duration, periodicity, sequence and density) that compose, in the aggregate, the endogenous time ofan organism. In this review the authors analyze some features of local networks in the hypothalamic nuclei and formulate the principles of neuropeptide effects underlying the homeostatic regulation of the endogenous time of an organism by hypothalamus.

Morphological characteristics of the elements of vessel walls in the microvasculature of rat neocortex were studied after perinatal hypoxia and subsequent introduction of salifen, a derivative of GABA, at long-term postnatal periods. It is shown that salifen at a therapeutic dose has a protective effect on the endothelium of blood vessels in the microvasculature of neocortex. It is found that after exposure to hypoxia followed by application of salifen no endothelial hypertrophy, appearance of numerous processes of endotheliocytes in the vascular lumen, and narrowing of the capillary lumen occur. The formation of la- mina densa is almost identical to that in the control. Swelling of perivascular astrocytes and reactive chan- ges of pericytes are also absent. In all layers of the neocortex the density of vessel distribution in the mic- rovasculature as well as their cross-sectional area in adult animals of the control group and after exposure to hypoxia and salifen application were approximately identical. It is shown that changes and restructu- ring of the capillary bed after exposure to hypoxia and application of salifen take place at earlier terms of development whereas by the maturity period stabilization of the structural parameters of the microvas- culature occurs. The protective effect of salifen on the elements of capillary walls determines the clinical effectiveness of its use and serves as a basis for further research in this direction.

The phospholipid and fatty acid content of erythrocytes in rat blood was studied after exposure to stress - swimming up to drowning. This stress was found to increase the content of phospholipids cha- racteristic for the membrane outer layer (phosphatidilcholine by 13 % and sphingomyelin by 23 %). At the same time a decrease in the content of acid phospholipids belonging to membrane inner layer was ob- served (phosphatidylethanolamine by 16 %, phosphatidyl serine by 14 % and monophosphoinositide by 23 %). The data obtained indicate that erythrocyte membrane under stress conditions undergoes certain structural changes which seem to have an effect on its functional properties. At the same time it was fo- und that the content of saturated, unsaturated and ounsaturation index? of fatty acids does not undergo es- sential changes under stress exposure studied thereby, possibly, compensating maintenance of functional properties of the erythrocyte membrane under conditions of the impaired phospholipid structure. On the basis of examining absorption spectra of lipid extracts it was found that stress evokes a two-fold spectrum growth in the range of 390-410 nm appropriate to the hem. The fact of appearance of the hem in the ext- ract indicates to saponification of hemoglobin evoked by changed pH of the erythrocyte internal environ- ment. Actually, in the process of lipid extraction the hemoglobim passes into a disordered state due to the effects of not only temperature and environmental pH but also due to those of organic solvents possessing lower, than water, ability to form hydrogen bonds. Probably, transesterification of a minor portion of phospholipids occurs during their extraction from erythrocytes with the chloroform-methanol mixture.

This paper reviews various aspects of the physiological and biochemical mechanisms directed to create special rheological conditions for blood flow called <> blood properties. The struc- tural features of the phospholipid composition of plasmatic membranes and cytoskeleton, the state of the intra- and extracellular ATP pool, ATPase ecto-enzymatic activity of nucleated and non-nucleated red blood cells of vertebrates are compared and thermal effects in nucleated erythrocytes investigated. A hypothesis based on literature and own data is suggested according to which the phenomenon of <> blood properties relies on a decrease in the relative viscosity of blood due to the thermal hydrolysis of extracellular ATP excreted by erythrocytes on their surface particularly strong during deformation stress in capillaries. We belive that in fish an important role in this process may belong to ecto-ATPases of erythrocyte plasmatic membranes. Due to generation of heat by the hydrolysis of extra- cellular ATP, the wall layer of the plasma appears to warm up. This could change the structure of the membrane bilayer and deform the cytoskeleton, thus providing the special rheological conditions for blood flow. Among the proofs of possible existence of this mechanism is heat production ability of nucleated red cells in fish revealed in our stymies.

Changes in electrical activity of neocortex after prenatal hypoxia (day 14 of embryogenesis - E14, 7 % 02 for 3 hours) and these combined with intracortical microinjection of epileptogenic 4-aminopyridine (4-AP) have been studied in adult rats. We analyzed the frequency-time parameters of electrocorticogram (ECoG) during sleep and wakefulness as well as spike-wave discharge (SWD) in 4-AP-induced epileptiform model. The results showed that in rats subjected to prenatal hypoxia the theta rhythm had a lower frequency and sleep spindles were characterized by lower spectral power in low-frequency domain in comparison with the control group. In rats with prenatal pathology delayed onset of epileptiform activi- ty and altered frequency distribution of the spectral power of 4-AP-induced SWD were revealed.