The Effect of Long-Term Emotional and Painful Stress on the Expression of Proinflammatory Cytokine Genes in Rats with High and Low Excitability of the Nervous System.

Stress plays an important role in the pathogenesis of anxiety and depressive disorders. Neuroinflammation is considered as one of the mechanisms by which stress alters the molecular and cellular plasticity in the nervous tissue and thus entails CNS dysfunction. The contribution of genetically determined features of the nervous system to the development of post-stress neuroinflammation has not been sufficiently studied. In this study, the dynamics of post-stress changes in mRNA levels of the il-1ß and tnf genes encoding proinflammatory cytokines interleukin-1 beta (IL-1ß) and tumor necrosis factor (TNF) were evaluated in the blood and brain of two rat strains with high and low excitability thresholds of the nervous system (HT and LT, respectively). Changes in IL-1ß and TNF mRNA levels were assessed by real-time PCR 24 h, 7, 24 and 60 days after long-term long-term emotional and painful stress in the blood and three brain structures involved in the development of post-stress pathology (prefrontal cortex, hippocampus, amygdala). In highly excitable LT rats, IL-1ß mRNA level in the hippocampus and amygdala increased compared to the control 24 days after stress termination, while in low-excitable HT animals, an increase in the level of IL-1ß mRNA was only detected in the hippocampus at the same time point. TNF mRNA level did not change in any of the rat strains at any of the post-stress time points. Genetically determined excitability of the nervous system is a promising marker of individual stress vulnerability, as manifested in post-stress disorders associated with developmental and time-course features of neuroinflammation.

The Effect of the Taste Receptor Protein T1R3 on the Development of Islet Tissue of the Murine Pancreas.

T1R3 protein, the main subunit of the sweet taste receptor and receptor of amino acid taste, is expressed in the epithelium of the tongue and gastrointestinal tract, in ß cells of the pancreas, hypothalamus, and numerous other organs. Recently, convincing evidences on the involvement of T1R3 in the control of carbohydrate and lipid metabolism, and the control of incretin and insulin production were obtained. In the study on Tas1r3-gene knockout mouse strain and parent C57BL/6J strain as a control, the data on the effect of T1R3 on morphological characteristics of Langerhans islets in the pancreas were obtained. In Tas1r3 knockout animals, we found a reduction in the size of islets and their density in pancreatic tissue as compared to the parent strain. In addition, a decrease in the expression of active caspase-3 in the islets of gene-knockout mice was demonstrated. The data obtained indicate that the lack of functioning gene encoding sweet taste receptor protein causes a dystrophy of the islet tissue and is associated with the development of pathological changes in the pancreas specific to type 2 diabetes mellitus and obesity in humans.

[THE REGULATING EFFECT OF DIPEPTIDES ON CELL PROLIFERATION IN NERVE TISSUE CULTURE IN MAMMALS AND ON ASSOCIATIVE LEARNING IN INSECTS].

The effect of dipeptides AspPro and AspSer and of their composing amino acids (asparagine acid--Asp, proline--Pro, serin--Ser) on the proliferative activity in the explants of cortex and subcortical structures of the rat brain and on the functional activity of CNS of the honeybee was studied. The square index defined as a proportion of the whole explant square to the square of its central zone was determined. The number of bees responded with the conditional reaction (proboscis extension in the direction to aromatized solution) after 1 min (short-term memory) and 180 min (long-term memory) was detected after single learning procedure. Both dipeptides, as well as the asparagine acid, stimulated an increase of the growth zone of the subcortical structure explants in rats and of the number of honeybees with retention of conditional reaction in the short-term/long-term memory independently of the effect of the second member of the dipeptide. The unidirectionality of the effect suggests the existence of common mechanisms of reception and signal transduction established during evolution that require the further study.

[Metabotropic receptor of the group I of the 5th subtype (ImGLuR5) in honeybee associative olfactory learning].

The work deals with study of character of localization in the honeybee head ganglion of metabotropic receptor ImGluR5 and its role in memory formation. With aid of pharmacological method (injections of antisense oligonucleotide and of selective receptor agonist and antagonist) and of behavioral criterion (formation and testing of preservation in memory of conditioned alimentary reflex for olfactory stimulus), there is first shown participation of the studied receptor in formation of the honeybee long-term memory. By using the immunohistochemical method, there is first revealed the predominant expression of the ImGluR5 receptor in the mushroom body Canyon cells responsible for the insect integrative activity. The present study, together with the previous ones, allows concluding about the presence in the honeybee head ganglion of the group I of metabotropic glutamate receptors with two subtypes 1 and 5 (ImGluR1,5) that have similar with mammalian pharmacological properties favoring preservation of the individually acquired experience in the long-term memory.

[On epigenetic regulation of process of formation of long-term memory].

The review summarizes current concepts on role of several covalent posttranslation chromatin modifications in the process of memory formation in vertebrate and invertebrate animals. There is described a chain of intracellular events from activation of receptors and signal pathways to change of the functional state of genome.

[The morphological basis of conditioned reflex in the honeybee Apis mellifera L].

A review. Works related to research into the neuroanatomical basis of associative learning in the honeybee (proboscis extension reflex) are summarized. Data on the brain organization of the honeybee are presented. The parallel neural pathways of conditioned and unconditioned stimuli are shown. Contribution of different brain structures and identified neurons (VUMmx1, PE1) in the formation of the proboscis extension reflex are discussed.

[Metabotropic glutamate receptors in the mechanisms of plasticity of central nervous system of the honeybee Apis mellifera].

Localization of metabotropic glutamate receptors (MGR) in head ganglion of honeybee Apis mellifera, and mechanisms of participation of activated MGR in CNS plasticity are investigated by means of complex approach using immunochemical, electrophysiological and behavioral methods. Influense of MGR activation on GABAergic system and ionotropic glutamate receptors (IGR) of AMPA- and NMDA-subtypes in studied. MGRa are revealed in lateral and medial calices of mushroom bodies. The inhibiting influence of MGR on AMPA- and NMDA receptors is shown using method of conditioned reflex. Previous activation of MGR neutralizes the inhibiting effect of GABA. Modulating role of heterogeneous MGR population in mechanisms of CNS plasticity on the level of glutamate-ergic synapse, and at interaction with GABAergic system is discussed.

[Behavioral and molecular effects of endogenic kynurenines deficit in the honeybee (Apis mellifera L.)].

The importance of tryptophan endogenous metabolites kynurenines in the long-term memory and functioning of the signal cascade GluR - LIMK1 - F-actin, mediating the long-term memory trace storage, was demonstrated. The deficit of kynurenines induced by allopurinol (tryptophanoxygenase inhibitor) suppressed the long-term memory, decreased the LIMK1 expression, and paradoxically increased the F-actin content in the honeybee brain. These data agree with the earlier findings in drosophila mutant vermilion (the mutation of tryptophanoxygenase gene).

Comparative analysis of the locations of the NR1 and NR2 NMDA receptor subunits in honeybee (Apis mellifera) and fruit fly (Drosophila melanogaster, Canton-S wild-type) cerebral ganglia.

The locations of the NR1 and NR2 subunits of the GABA receptor were studied in brain structures in insects--honeybees and fruit flies--using an immunohistochemical method. The specificities of the antibodies to the NR1 and NR2 subunits were confirmed by the antisense knockdown method for the NR1 subunit and western blotting. The data obtained here lead to the conclusion that the distributions of the NR1 and NR2 subunits of the NMDA receptor complex in the cerebral ganglia of the honeybee and fruit fly are similar; areas with the highest concentrations of NR1 and NR2 subunits were identified, and these were found to be different in the different insects. This is associated with the behavioral characteristics of these two insect species.

[Mutations in structural genes of tryptophan metabolic enzymes of the kynurenine pathway modulate some units of the L-glutamate receptor--actin cytoskeleton signaling cascade].

Methods of immunohistochemistry and fluorescent staining was used to study the localization and amounts of protein components of the signal cascade connecting the receptor link (NMDA-subtype glutamate receptor) with actin of the cytoskeleton in the head ganglia of Drosophila strain Canton-S (wild type, control) and strains carrying mutations vermilion, cinnabar, and cardinal, which sequentially inactivate tryptophan-hydrolyzing enzymes during its metabolism into ommochrome. The obtained data are evidence for modulatory effects of genes controlling the kynurenine pathway of tryptophan metabolism on the major components of the signal cascade: the initial link (NMDA receptor, postsynaptic density protein-95, a structural protein involved in receptor localization and internalization), the intermediate link (limkinase-l, the key neuronal enzyme in actin remodeling) and the final link (f-actin, the critical factor in the morphogenesis of synaptic structures and, hence, in the processes of synaptic plasticity, learning and memory). It is suggested that kynurenine acid (an endogenous nonspecific antagonist of L-glutamate receptor) and 3-hydroxykynurenine capable of inducing a nonspecific stimulating effect are biochemical intermediates of the effects of these genes.

[Comparative analisys of localization NR1 and NR2 subunits of NMDA-receptor in the brain structures in honeybee (Apis mellifera L.) and Drosophila (Drosophila melanogaster, wild type canton-S)].

Localization NR1 and NR2 subunits of NMDA-receptor was studied in brain structures of the honeybee and Drosophila by immunohistochemistry. The Western-blotting and NR1 subunit antisense-knockdown confirmed specificity of antibodies to NR1 and NR2 subunits. The data obtained demonstrated similar distribution of NR1 and NR2 subunits of NMDA-receptor in the insect brain (cranial ganglion). The brain regions with the highest expression NR1 and NR2 were different in the honeybee and Drosophila. This can be associated with behavioral repertoire peculiarities in these insects.

Central non-NMDA receptors of a honey bee with hereditary kynurenine deficiency.

Pharmacological characteristics of non-NMDA receptors involved in associative learning were studied in wild honey bees (normal) and carriers of snow laranja mutation (kynurenine deficiency) by pharmacological analysis and behavioral criteria. The effects of systemic injections of non-NMDA receptor agonists (AMPA, kainic, quisqualic, and domoic acids), AMPA receptor antagonist (NS257-HCl), and AMPA receptor modulator (cyclothiaside) on retention of conditioned reflexes in short-term memory (1 min after the end of learning) were studied. The pharmacological characteristics of non-NMDA receptors were changed in snow laranja mutants with kynurenine deficiency.