Effect of antagonists of serotonin receptors on modulation with serotonin of synaptic activity of projectional neurons of rat amygdala dorsolateral nucleus

The work studies role of different receptor types of serotonin (5-hydroxytryptamine; 5-HT) in the process of synaptic activity modulation with 5-HT of rat dorsolateral amygdala projection neurons. The selective antagonist of 5-HT_1,2 receptors methylsergid maleate was shown to suppress the 5-HT inhibitory action on amplitude of the postsynaptic currents evoked by glutamate and GABA, whereas the antagonist of 5-HT_3,4 receptors SDZ202-557 produced no effect on the above-mentioned 5-HT action. The obtained action indicates that the 5-HT modulatory effect on the projectional neuron synaptic inputs is mediated by 5-HT receptors of the 1 and 2 types.     

Functional changes in mitochondrial properties as a result of their membrane cryodestruction. I. Influence of freezing and thawing on succinate-ferricyanide reductase of intact liver mitochondria

The interaction of the succinate dehydrogenase complex of rat liver mitochondria with an artificial electron acceptor (K3Fe(CN)6), impermeable to the mitochondrial membrane as an index of a cryoinjury is investigated. It is shown that the freeze-thawing stimulates succinate-ferricyanide reductase (SFCR) activity of intact mitochondria. The increase of the freezing and thawing rates leads to a decrease in the released SFCR activity. The released SFCR activity after low-temperature treatment is a consequence of a nonspecific change in membrane ferricyanide permeability. The released SFCR activity decreases as the freezing and thawing rates increase.     

Synthesis of a repeating unit and the dimer of the repeating unit of the major chain of Shigella flexneri O-antigen polysaccharide

Methyl glycoside of the tetrasaccharide GlcNAc(beta 1-2)Rha(alpha 1-2)Rha(alpha 1-3)Rha, which represents a repeating unit of the basic chain of Shigella flexneri O-antigenic polysaccharides, was synthesized using acylated monosaccharide synthons. A dimer of the repeating unit, octasaccharide [GlcNAc(beta 1-2)Rha(alpha 1-2) Rha(alpha 1-3)Rha(alpha 1-3)]2-OMe was obtained by TrClO4-catalyzed condensation of two tetrasaccharide blocks.     

Transmembranous currents of isolated spinal cord neurons of ammocete—Larva of the lamprey <Emphasis Type="Italic">Lampetra fluviatilis</Emphasis>

The work is carried out with aid of the patch-clamp method in the “whole cell” modification. There were studied potential-activated and chemosensitive currents of isolated spinal neurons of the lamprey larva-ammocete. The described properties of the currents indicate their similarities with those in adult lampreys.     

Cytology of oocytes in ground squirrels (Citellus citellus L.)

Oocytes of primordial, primary, growing, and Graaf follicles of the ovaries of 96 ground squirrels (Citellus citellus L.) were studied during the four seasons of the year. Multilamellar bodies in the oocytes were observed by electron microscopy. The bodies underwent changes during the follicle growth. The vesicles included in the multilamellar bodies were filled with an amorphous substance, while in Graaf follicles trapezoidal, rhomboidal, and hexagonal inclusions were found. The primordial follicle of the oocyte had no Balbiani body. In the hibernating ground squirrel the functions of the Balbiani body were probably performed by the multilamellar bodies, which were considered to be analogous to the Balbiani body.     

Homeostatic role of calcitonin antibodies in calcium metabolism in experimental diabetes mellitus

In experimental alloxan diabetes marked hypocalcemia and hyperglycemia are observed in the blood of rats during the acute period of the disease (from 1.5 to 2 months). After 2.5-3.5 months of diabetes calcium level reaches the upper normal limit. Simultaneously, antibodies to calcitonin appear. It is quite likely that excessive calcitonin secretion, leading to hypocalcemia, decreased insulin secretion and hyperglycemia take place in the acute stage of diabetes. When diabetes persists the antibodies to calcitonin which reveal a homeostatic reaction blocking the excess of calcitonin appear. This normalizes the level of calcium in the blood and prevents the further increase in the blood sugar level.     

In vitro and in silico investigation of interferonogenic analogues of nucleic acids, artificially programmed to block the initial stages of HIV infection of cells

Approaches to the molecular design of antiviral agents based on the principals of adequacy and mimicry to biopolymers have been discussed. The approaches permit for the reproduction of pharmaceutically valuable properties of the polymeric basis (core) and to create novel nongenetic “programs” of bioactivity of macromolecules by means of grafting specific side group combinations to this core. In vivo experiments have shown that the immunostimulating (in particular, interferon-inducing) antiviral potency of nucleic acids (NAs) is a characteristic of carboxylic acid analogues with an NA-type order of furan and anionic component alteration in the polymer chain. Controlled grafting of virus-targeted side groups of the polymeric basis leads to the direct blockage of viral infection in vitro as an additional antiviral effect. In this work, the inhibition of the early penetration stages of human immunodeficiency virus type 1 (HIV-1) in cells has been studied. Modelling of the macromolecule interaction with the most probable target (the virus-cell fusion mediator (an α-helical complex of the N- heptad repeat regions of three HIV-1 envelope glycoprotein gp41 transmembrane molecules) was performed. Computational docking of the experiment in silico resulted in the clarification of the putative mechanisms and parameters for the programming of site-tropic, axial, and belting blockages of the target via the application of an alicyclic-type side group. The discovered opportunities of multipoint axial cobelting blockage of a target opens up new prospects for the prevention/therapy of AIDS, as well as for other viral infections that use similar systems of envelope fusion peptides (of the first and third types) for penetration into cells.     

Seasonal changes of the ovarian atretic follicles of the ground squirrel (Citellus citellus L.)

The ovaries of 84 ground squirrels (C. Citellus L.) were studied during the four seasons of the year. The ovarian atretic follicles were examined by histological methods and by electron microscopy. The histoenzyme activities of NAD.H2-tetrazolium reductase, glucose-6-phosphate dehydrogenase, and 3 beta-hydroxy-delta 5-steroid dehydrogenase were photometrically demonstrated. The steroid-producing atretic follicles were mainly described as they reached their highest enzyme activity during the lactation period in April. The atresia of the primordial and primary follicles was manifested by disappearance of the oocyte and preservation of the granulose cells surrounded by basal lamina. Atresia of follicles with two oocytes was a typical process for the ground squirrel. Later on the oocytes and the granulose cells around it disappeared. The remaining part of the follicle continued its development and reached maturity. Atresia was observed mainly in March, April, and May.