卷 59, 编号 6 (2023)

The renal glomerulus is a unique structure that distinguishes the nephrons of vertebrates from the nephridia of invertebrate animals, providing a direct connection between the circulatory and excretory systems and the most effective control of the composition of the internal environment due to the significant intensification of filtration. The modern ideas about the structure of the glomerular filtration barrier in representatives of all major groups of vertebrates (cyclostomes, fishes, amphibians, reptiles and birds, mammals) were reviewed. Emphasis is placed on the role of the charge of the glomerular barrier structures for its selective properties; approaches to studying the contribution of the anionic components of the renal filter to preventing the loss of plasma proteins are described. The main models of the glomerular filter functioning presented in the literature are considered. Negative charge has been demonstrated to be a distinctive feature of the glomerular filter in all vertebrates. It was shown that a multiple increase of the glomerular filtration rate (from lower vertebrates to birds and mammals) was accompanied by a number of structural changes that ensured the passage of a significant volume of water and dissolved low-molecular substances through the glomerular filter: an increase in the number and ordering of fenestrae in the endothelium of glomerular capillaries, thinning of the glomerular basement membrane and complete exclusion of cellular elements from it. It has been shown that comparative physiological data on the glomerular filter in different groups of vertebrates most strongly confirm the electrokinetic model of the glomerular filtration, since it explains the importance of the evolutionarily conservative structure of podocytes and the role of a set of fixed anionic charges in the filter wall to prevent the loss of macromolecules (primarily proteins) from blood at different intensities of the ultrafiltration.

A comparative study of the morphology of descending neurons connecting the supraesophageal ganglion and thoracic ganglia in cockroaches of the family Blaberidae, which differ in protective behavior and flight ability, was carried out. The neuronal structure of these families was compared with the descending neurons of the cockroach Periplaneta americana. The number, spatial distribution, and arrangement of axons and dendrites of descending neurons of cockroach Leucophaea maderae, Gromphadorhina portentosa, Blaberus craniifer, Nauphoeta cinerea (Blaberidae) were found to be similar. Neurons homologous to the ocellar, mechanosensory, and visual descending neurons described in the cockroach Periplaneta americana were found. It is suggested that during the evolution of the cockroach species, the adaptive behavior at danger was changed by transforming sensory inputs and motor responses, while the system of descending neurons remains stable.

Insulin controls both systemic glucose homeostasis and the functional activity of the brain. Insulin content and the activity of the insulin signaling system decreases in the brain in diabetes mellitus type 2 (DM2). It gives rise to disorders of energy metabolism, including hypometabolism of glucose in the brain, and to cognitive dysfunctions. The deficiency of hormone in the brain can be restored by intranasally administered insulin (IAI). It is also reasonable to use it in combination with substances with neuroprotective properties, including complex glycosphingolipids gangliosides, in order to increase the effectiveness of IAI for the correction of brain functions. Intranasal way of ganglioside delivery (IAG) to the brain can be explored as well. The aim of the research comprised the evaluation of efficiency of separate and combined IAI and IAG use to correct the cognitive impairment in Wistar rats with DM2 using the Morris water maze (MWM) and analysis of expression of proteins (BDNF, GLUT-1, GLUT-3, GLUT -4, GFAP, PSD95) and activity of protein kinases (Akt, GSK3β, ERK1/2) involved in learning and long-term memory formation in the hippocampus. IAI and IAG improved spatial orientation of rats with DM2in the MWM, and the effect of combined use of IAI and IAG was similar to the effect of each substance used separately. Owing to combined IAI and IAG the activity of effector protein kinases (Akt and ERK1/2) was maintained at the same level as in control rats while IAI monotherapy resulted in the reduced level of their phosphorylation. The level of GSK3β phosphorylation at Ser⁹ was also increased after combined treatments with insulin and gangliosides which is protective against tauropathy. Thus, the combined application of IAI and IAG improves the functional state of the components of the insulin system in the brain of rats with DM2, although it does not significantly enhance the effects of IAI on long-term memory.

In experiments on rats, the participation of co-mediators of the sympathetic nervous system in the suppressive effect of deep cooling on the antibody-forming function of the spleen was studied. Studied: 1) the effect of deep cooling (decrease in deep temperature by 3–4°С), 2) the introduction of the mediator of the sympathetic nervous system norepinephrine (NE, 1 mg/ml), 3) its co-transmitter ATP (0.01 mg/ml and 10 mg/ml) and 4) P2X-purinergic receptor blocker PPADS on the number of antibody-forming cells of the spleen in response to immunization with sheep erythrocytes. Deep cooling as well as ATP inhibited, while NE stimulated antibody formation in the spleen. Blockade of P2X-purinergic receptors by PPADS stimulated antibody formation in the norm. Against the background of blockade of P2X-purinergic receptors, the inhibitory effect of ATP and deep cooling on antibody formation was not manifested. The results obtained indicate the opposite effects of co-mediators of the sympathetic nervous system on antibody formation in the spleen and suggest that the inhibitory effect of cold on antibody formation in the spleen occurs with the participation of ATP through P2X-purinergic receptors.

The effect of moderate hypoxia on the processes of energy metabolism in the tissues (gills, hepatopancreas) of the Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) was studied experimentally. The control group of mollusks contained 6.8–6.9 mgO₂ l^–1, the experimental group at 1.9–2.0 mgO₂ l^–1. In both cases, the water temperature was 22 ± 1°C, the salinity was 17–18‰. The exposition – 72 hours. The oxygen content in the water was lowered by bubbling with nitrogen gas for 4–5 hours. In conditions of moderate hypoxia, a complex of reactions aimed at maintaining the energy status of tissues developed in the body of the Mediterranean mussel. Aerobic processes were clearly limited, as evidenced by a decrease in succinate dehydrogenase (SDH) activity. At the same time, the processes of anaerobic glycolysis intensified. The activity of aldolase, malate dehydrogenase (MDH) increased, the content of pyruvate in tissues increased. This was not accompanied by an increase in lactate dehydrogenase (LDH) activity and an increase in lactate content. The tissues retained their original energy status. The content of the ATP fraction remained at the level of control values, which reflected the adaptive orientation of the reorganization of tissue metabolism. The ability of hepatopancreas to accumulate ADP and AMP fractions from circulation systems under experimental hypoxic load was noted.