Regulation of Apoptosis in Nonapeptidergic Neurons of Rat Hypothalamus by Catecholamines in Experiments in vitro

Effects of noradrenaline (NA) and dopamine (DA) on apoptosis of nonapeptidergic neurons of supraoptic (SON) and paraventricular (PVN) nuclei of hypothalamus of male Wistar rats was studied in experiments in vitro. Incubation of hypothalamic sections in the medium with added NA was shown to induce an increase of the amount of pro-apoptotic protein caspase-9 in the nonapeptidergic neurons of the SON and PVN. A comparison of the level of neuronal NO-synthase with the level of caspase-9 expression in these neurons allows concluding that NA leads to initiation of apoptosis in neurons of the SON with mediation by nitric oxide (NO). In the PVN, the NA-induced initiation of apoptosis does not depend on the NO level. Addition of DA to the incubation medium results in an increase of the caspase-9 amount only in PVN neurons regardless of the NO content. The absence of neuronal death after the NA-induced increase of the caspase-9 level in the cells of SON and PVN seems to be due to increased expression of the anti-apoptotic protein bcl-2. Protection of the PVN neurons from death after addition of DA to the incubation medium is probably independent of the expression level of bcl-2. Thus, in the nonapeptidergic neurons of the SON and PVN, which are related by origin and by performed functions, modulation of the process of apoptosis by elevated concentrations of NA and DA is realized by different mechanisms.     

Pifithrin-α Inhibits Neural Differentiation of Newborn Cells in the Subgranular Zone of the Dentate Gyrus at Initial Stages of Audiogenic Kindling in Krushinsky–Molodkina Rat Strain

Journal of Evolutionary Biochemistry and Physiology - One of the main challenges of modern neurobiology is finding approaches to prevent structural abnormalities in the brain, specifically, in the...     

Inhibition of cGMP-dependent protein kinase II by its own splice isoform

cGMP- and cAMP-dependent protein kinases (cGK I, cGK II, and cAK) are important mediators of many signaling pathways that increase cyclic nucleotide concentrations and ultimately phosphorylation of substrates vital to cellular functions. Here we demonstrate a novel mRNA splice isoform of cGK II arising from alternative 5' splicing within exon 11. The novel splice variant encodes a protein (cGK II Delta(441-469)) lacking 29 amino acids of the cGK II Mg-ATP-binding/catalytic domain, including the conserved glycine-rich loop consensus motif Gly-x-Gly-x-x-Gly-x-Val which interacts with ATP in the protein kinase family of enzymes. cGK II Delta(441-469) has no intrinsic enzymatic activity itself, however, it antagonizes cGK II and cGK I, but not cAK. Thus, the activation and cellular functions of cGK II may be determined not only by intracellular cGMP levels but also by alternative splicing which may regulate the balance of expression of cGK II versus its own inhibitor, cGK II Delta(441-469).     

Nootropic and analgesic effects of Semax following different routes of administration

Heptapeptide Semax (MEHFPGP) is the fragment of ACTH(4-10) analogue with prolonged neurotropic activity. The aim of the present work was to study the Semax effects on learning capability and pain sensitivity in white rats following intraperitoneal and intranasal administration in different doses. Semax nootropic effects were studied in the test of acquisition of passive avoidance task. Pain sensitivity was estimated in Randall-Selitto paw-withdrawal test. It was shown that Semax exerts nootropic and analgesic activities following intraperitoneal administration. Analysis of dependence of these effects on dose resulted in different dose-response curves. Following intranasal administration, Semax was more potent in learning improvement compared to intraperitoneal administration. The peptide failed to affect the animal pain sensitivity following intranasal administration as opposed to intraperitoneal administration. The data obtained suggest different mechanisms and brain structures involved in realization of the nootropic and analgesic effects of Semax.     

Apoptotic signaling proteins: possible participation in the regulation of vasopressin and catecholamines biosynthesis in the hypothalamus

The role of apoptotic signaling proteins for long-lived neurons in the mature brain is poorly understood. Recently, we have shown that water deprivation leads to the activation of vasopressin (VP) secretion and expression of Bcl-2 and caspase-9 apototic proteins in the hypothalamus of the rat brain. In the present work, we continued to study a possible relationship between the functional activity of neurosecretory cells of the hypothalamus and apoptosis related proteins. We found that water deprivation leads to simultaneous activation of synthesis of VP and p53 and Bcl-2 apoptotic proteins in the mouse brain. To study a possible effect of apoptotic proteins on the functional state of hypothalamic neurons, the VP and tyrosine hydroxylase (TH) synthesis were analyzed in p53, p21^Waf1/Cip1 and Bcl-2 deficient mice. Loss of p53 and Bcl-2 significantly reduced VP synthesis in paraventricular and supraoptic nuclei and TH expression in arcuat, periventricular and zona incerta nuclei of the hypothalamus. Surprisingly, in contrast with the loss of p53, the inactivation of p21^Waf1/Cip1 up-regulates the expression of VP and TH. These data indicate that p53, p21^Waf1/Cip1 and Bcl-2 proteins, besides affecting cell cycle, tumor suppression and apoptosis, may act as modulators of neurosecretory activity of hypothalamic neurons; however, this problem remains to be determined more detailed.     

Genetic diversity of the genus Lactobacillus bacteria from the human gastrointestinal microbiome

The species and strain genetic diversity of bacterial cultures belonging to the genus Lactobacillus, which were isolated from the gastrointestinal microbiome of the human population living in the former Soviet Union in the years 1960-1980, was studied. The bacteria demonstrated probiotic characteristics. Phylogenetic analysis of sequences of the gene coding for 16S rRNA detected earlier by us, showed that the gene found in bacteria isolated from the intestinal content of healthy adults and represented by species L. plantarum, L. helveticus, L. casei/paracasei, L. rhamnosus, and L. fermentum has high homology (97-100%) with this gene in type representatives of the species. The genotypic and strain diversity of cultures was studied using RAPD-PCR and nonspecific primers. This method with the use of the ERIC-1 primer gave reliable and reproducible results as compared that using with M13 and MSP primers and allowed the identification of examined bacteria belonging to the genus Lactobacillus at the level of species and certification at the strain level.     

Role of Catecholamines in Regulation of the Functional State of Vasopressinergic Cells of the Rat Hypothalamus

In in vivo and in vitro experiments there have been shown different mechanisms of regulation of hypothalamic vasopressinergic neurons, including regulation due to changes of activity level of brain catecholaminergic and NPY-ergic neurons innervating hypothalamic vasopressinergic cells. We demonstrated in in vitro experiments that dopamine and noradrenaline had no effects on vasopressin expression, but inhibited its release from cell perikarya in supraoptic and paraventricular nuclei of hypothalamus. Besides, activity of vasopressinergic neurons might probably be regulated via activation of synthesis of these neurotransmitters in vasopressinergic cells themselves in the supraoptic and paraventricular nuclei. To activate synthesis of various neurotransmitters, in our case, catecholamines and NPY, in vasopressinergic neurons, different stimuli adequate to trigger or activate synthesis of these substances are required. Synthesis of catecholamines in vasopressinergic cells of supraoptic and paraventricular nuclei was revealed after immobilization stress and adrenalectomy. NPY is synthesized in neurons of hypothalamic neurosecretory centers in norm, and its synthesis increases at disturbances of NPY-ergic innervation of vasopressinergic cells.     

Distribution, cellular localization, and postnatal development of VASP and Mena expression in mouse tissues

Vasodilator-stimulated phosphoprotein (VASP) and mammalian Enabled (Mena) are members of the proline-rich Ena/VASP protein family that links the cell membrane proteins, signal transduction pathways, and the actin cytoskeleton. VASP and Mena, substrates of cyclic nucleotide-dependent protein kinases, are associated in different cell types with microfilaments, focal adhesions, cell-cell contacts, and highly dynamic membrane regions. Here, the analysis of mRNA and protein expression, cellular localization, and postnatal development of VASP in different mouse tissues is reported and compared with that of Mena. The expression levels of VASP and Mena differ markedly among various tissues and cell types. The highest levels of VASP are observed in platelets, but stomach, intestine, spleen, lung, and blood vessels are also rich sources of VASP. Mena is abundantly expressed in brain, whereas it is not detectable in platelets and spleen. In intestine and stomach, prominent VASP and Mena immunoreactivity is detected in intestinal smooth muscle cells and blood vessels and cellular membranes of epithelial cells. In kidney, VASP and Mena are abundantly expressed in glomerular mesangial cells and in papilla. VASP and Mena immunoreactivity in heart is associated with blood vessels and with the intercalated discs of cardiac myocytes, where they colocalize with connexin-43. During postnatal development of heart, the level of VASP and Mena expression gradually decreases from neonatal to adult animals. The data demonstrate a clear colocalization of VASP and Mena in cells of stomach, intestine, kidney, and heart. These data and other recent developments suggest that proteins of the Ena/VASP family exert similar functions and may compensate for each other in these tissues.