Effect of adenosine-5'-O-(beta, gamma-dichloromethane)triphosphate on ATP-activated currents in sensory neurons in rats

The action of beta,gamma-dihalogenmethane derivatives of ATP on ATP receptors has been studied in the sensory neurons of rats. beta,gamma-Dichloromethane-ATP and beta,gamma-dibromomethane-ATP are competitive blockers and beta,gamma-difluoromethane-ATP is a partial agonist of ATP receptors. At present, beta,gamma-dichloromethane-ATP is the most efficient of the known competitive blockers of these receptors (Ki = 2.10(-5) M). The data obtained confirm that beta- and gamma-phosphates of ATP play an important role in the activation of ATP receptors.     

Nervous regulation of the proliferative activity of tissues]

The work generalizes the literature evidence on the problem of nervous regulation of the tissue proliferative activity as well as personal data demonstrating the increased rate of tissue proliferation under conditions of deep inhibition of the function of the sympathetic part of the nervous system obtained by means of immunosympathectomy. It is supposed that the regulating effect of the sympathetic part of the nervous system upon the proliferative activity of tissues is mediated by adrenaline, acting as a cofactor of chalon mechanism of the intratissue regulation of the cellular proliferation.     

Novel agonists of melatonin receptors as promising hypotensive and neuroprotective agents for therapy of glaucoma

Melatonin is a pineal hormone that has a capacity to lower intraocular pressure; it exhibits neuroprotective and antioxidant properties that make it possible to use melatonin in the therapy of glaucoma. Melatonin analogs demonstrating affinity to melatonin receptors are promising candidates for application as antiglaucomatous agents. Chemical modification of the melatonin structure can increase efficiency, bioavailability, and selectivity of melatonin analogs. We have designed and synthesized a number of new 2-oxindole derivatives, the ligands of melatonin MT3 receptors; these analogs are characterized by the ability to lower intraocular pressure in normotensive rabbits and high antioxidant activity against hydroxyl radical and superoxide anion-radical. New ligands significantly exceeding melatonin in antioxidant activity can be also applicable for the development of therapeutic agents for treatment of oxidative stress. The maximal hypotensive effect of the analogs was comparable to and lasted longer than that of melatonin. Combination of these properties suggests potential used of the analyzed melatonin analogs in complex therapy of glaucoma.     

Expression of human B-Cell specific receptor FCRL1 in healthy individuals and in patients with autoimmune diseases

The expression levels of the FCRL1 gene, which encodes a human B-cell surface receptor, were compared in healthy individuals and patients with autoimmune diseases. The expression levels were evaluated using DNA dot hybridization on membranes with spotted cDNA samples derived from blood-cell sub-populations of patients with autoimmune diseases. Quantification of the hybridization signals showed that FCRL1 expression in peripheral blood B-lymphocytes of patients with multiple sclerosis, lupus anticoagulants, Takayasu’s arteritis, and von Willebrand disease was significantly higher than in healthy individuals. Monoclonal and polyclonal FCRL1-specific antibodies that enable FCRL1 detection in Western blotting, immunohistochemistry, and flow-cytometry assays were generated. It was found that FCRL1 is expressed on the surfaces of mature CD19+ B-cells. In the tonsils, FCRL1-positive cells were located in the crypt area, i.e., in the mantle zone of secondary lymphoid follicles and among the cells of lymphoid epithelium. FCRL1-positive cells were also found in B-cell follicles of the spleen.     

The isolation of highly purified bacillary ribonucleases from recombinant strains of Escherichia coli]

Active and inactive highly purified extracellular alkaline ribonucleases (barnase) from recombinant Escherichia coli have been prepared according to the industrial technology of Bacillus intermedius ribonuclease purification. Electrophoretic parameters and ultraviolet spectra characterize these preparations as homogeneous proteins. Immunochemical test system of identification of inactive RNAse for its purification has been worked out.     

Biological and chemical characteristics of allergen preparations from Neisseria (N. meningitidis, N. gonorrhoeae, N. perflava)]

Various methods of isolating allergen fractions from N. meningitidis, N. gonorrhoeae and N. perflava were tested. The biological activity of the preparation was found to depend on the method of its production, which determined its chemical composition. When gonococcal and meningococcal allergens and N. perflava allergen were used in skin tests, cross reactions were observed. Nevertheless, as the intensity and size of skin reaction was much greater when a homologous preparation was administered, it was possible to differentiate the presence of sensitization to a definite microbial species. Electrophoresis in acrylamide gel revealed the heterogeneity of allergen preparations. The ability of the preparation to induce skin reaction was not connected with its serological properties.     

Central representation of the anterior lateral line nerve in dwarf catfish]

The central distribution of the anterior lateral line nerve (ramus) (NLLa) were studied in the pygmean sheat-fish (Ictalurus nebulosus) by means of the method of Nauta--Gygax. NLLa, as well as posterior lateral line nerve (NLLp), projects topographically on the nucleus medialis of the acoustic-lateral area. Within the nucleus medialis NLLa can be traces in the rostro-lateral parts. A majority of NLLa fibres can be followed ipsilaterally, although a definite contralateral contribution also exists. It is concluded that NLLa, representing the electro- and mechanoreceptors of the head region, distributes predominantly within the rostral part of the medial nucleus, while NLLp, representing the trunk receptors, distributes in the caudal half of the medial nucleus. There is some overlapping within the middle part of the nucleus.     

Membrane responses to changes in the extracellular potassium concentration in isolated hippocampal pyramidal neurons

The responses of freshly isolated hippocampal pyramidal neurons to rapid, elevations of the external potassium concentration ([K⁺] _out ) were investigated using the whole-cell variation of a patch-clamp technique. An elevation of [K⁺] _out induced a two-phase inward current at the membrane potentials more negative than the reversal potential for K ions. This current consisted of a leakage, current and a time-dependent current (τ=40–50 msec at 21°C), the latter designated below asI _ΔK. It displayed first-order activation kinetics that showed neither voltage, nor concentration dependence. The amplitude of this current was determined by the external K⁺ concentration and increased with hyperpolarization. Voltage dependence ofI _ΔK measured within the range from −20 to −120 mV was similar to that for inward rectifier. Activation ofI _ΔK was utterly dependent on Na⁺; substitution of extracellular Na⁺ with choline chloride almost completely depressedI _ΔK.I _ΔK was absent in the cells freshly dissociated from the nodosal and dorsal root ganglia. This suggests that this earlier unrecognized current is instrumental in preserving densely packed hippocampal pyramidal neurons from sudden increases in [K⁺] _out and following spontaneous over-excitation. It prevents the neurons from responding to K⁺-induced depolarizations by slowing down potassium influx.