Using histochemical analysis (NADPH-diaphorase, Fluoro-Jade B dye and bis-benzimide 33342 Hoechst) we studied the influence of intraperitoneal administration of nicotine (NIC), kainic acid (KA) and combination of both these substances on hippocampal neurons and their changes. In experiments, 35-day-old male rats of the Wistar strain were used. Animals were pretreated with 1 mg /kg of nicotine 30 min prior to the kainic acid application (10 mg/kg). After two days, the animals were transcardially perfused with 4 % paraformaldehyde under deep thiopental anesthesia. Cryostat sections were stained to identify NADPH-diaphorase positive neurons that were then quantified in the CA1 and CA3 areas of the hippocampus, in the dorsal and ventral blades of the dentate gyrus and in the hilus of the dentate gyrus. Fluoro-Jade B positive cells were examined in the same areas in order to elucidate a possible neurodegeneration. In animals exposed only to nicotine the number of NADPH-diaphorase positive neurons in the CA3 area of the hippocampus and in the hilus of the dentate gyrus was higher than in controls. In contrast, KA administration lowered the number of NADPH-diaphorase positive cells in all studied hippocampal areas and in both blades of the dentate gyrus. Massive cell degeneration was observed in CA1 and CA3 areas of the hippocampus and in the hilus of the dentate gyrus after kainic acid administration. Animals exposed to kainic acid and pretreated with nicotine exhibited degeneration to a lesser extent and the number of NADPH-diaphorase positive cells was higher compared to rats, which were exposed to kainic acid only., V. Riljak, M. Milotová, K. Jandová, J. Pokorný, M. Langmeier., and Obsahuje bibliografii a bibliografické odkazy
In a previous study of a kindling model using stimulation of the entorhinal cortex we found a redistribution of synaptic vesicles into the close vicinity of the active zone of synapses of Type I (Gray 1959) in the hippocampal gyrus dentatus. In this paper, ultrastructural studies of the same model are being continued using planimetry of the synaptic apparatus. A significant increase of the postsynaptic apparatus, area enlargement by 53 %, increase of the perimeter by 28 % and shape irregularity are being reported. No changes in shape or in size have been demonstrated in presynaptic structures or in the morphology of presynaptic mitochondria. These findings are discussed in relation to increased functional readiness of the synapses as signs of active reconstruction of the synaptic apparatus.
The present study investigated the effects of nesfatin-1 on gastric distension (GD)-responsive neurons via an interaction with corticotropin-releasing factor (CRF) receptor signaling in the ventromedial hypothalamic nucleus (VMH), and the potential regulation of these effects by hippocampal projections to VMH. Extracellular single-unit discharges were recorded in VHM following administration of nesfatin-1. The projection of nerve fibers and expression of nesfatin-1 were assessed by retrograde tracing and fluoro-immunohistochemical staining, respectively. Results showed that there were GD-responsive neurons in VMH; Nesfatin-1 administration and electrical stimulation of hippocampal CA1 sub-region altered the firing rate of these neurons. These changes could be partially blocked by pretreatment with the non-selective CRF antagonist astressin-B or an antibody to NUCB2/nesfatin-1. Electrolytic lesion of CA1 hippocampus reduced the effects of nesfatin-1 on VMH GD-responsive neuronal activity. These studies suggest that nesfatin-1 plays an important role in GD-responsive neuronal activity through interactions with CRF signaling pathways in VMH. The hippocampus may participate in the modulation of nesfatin-1-mediated effects in VMH., H. Feng, Q. Wang, F. Guo, X. Han, M. Pang, X. Sun, Y. Gong, L. Xu., and Obsahuje bibliografii
Depression is a complex disorder related to chronic inflammatory processes, chronic stress changes and a hippocampal response. There is a increasing knowledge about the role of glial cells in nutrient supply to neurons, maintenance of synaptic contacts and tissue homeostasis within the CNS. Glial cells, viewed in the past as passive elements with a limited influence on neuronal function, are becoming recognized as active partners of neurons and are starting to be discussed as a possible therapeutic target. Their role in the pathogenesis of depressive disorders is also being reconsidered. Attention is devoted to studies of the different types of antidepressants and their effects on transmembrane signaling, including levels of α subunits of G proteins in C6 glioma cells in vitro as a model of postsynaptic changes in vivo. These models indicate similarities in antidepressant effects on G proteins of brain cells and effector cells of natural immunity, natural killers and granulocytes. Thus, an antidepressant response can exhibit certain common characteristics in functionally different systems which also participate in disease pathogenesis. There are, however, differences in the astrocyte G-protein responses to antidepressant treatment, indicating that antidepressants differ in their effect on glial signalization. Today mainstream approach to neurobiological basis of depressive disorders and other mood illnesses is linked to abnormalities in transmembrane signal transduction via G-protein coupled receptors. Intracellular signalization cascade modulation results in the activation of transcription factors with subsequent increased production of a wide array of products including growth factors and to changes in cellular activity and reactivity., M. Páv, H. Kovářů, A. Fišerová, E. Havrdová, V. Lisá., and Obsahuje bibliografii a bibliografické odkazy
The cellular processes underlying individual differences in the Woring Memory Capacity (WMC) of humans are essentially unknown. Psychological experiments suggest that subjects with lower working memory capacity (LWMC), with respect to subjects with higher capacity (HWMC), take more time to recall items from a list because they search through a larger set of items and are much more susceptible to interference during retrieval. However, a more precise link between psychological experiments and cellular properties is lacking and very difficult to investigate experimentally. In this paper, we investigate the possible underlying mechanisms at the single neuron level by using a computational model of hippocampal CA1 pyramidal neurons, which have been suggested to be deeply involved in the recognition of specific items. The model makes a few experimentally testable predictions on the cellular processes underlying the cumulative latency in delayed free recall experimentally observed in humans under different testing conditions. The results suggest, for the first time, a physiologically plausible explanation for individual performances, and establish a proof of principle for the hypothesis that HWMC individuals use a larger portion of the apical tree with a correlated higher level of synaptic background noise.
This review, which summarizes our findings concerning the long-term effects of pre-, peri- and postnatal factors affecting development, nociception and sensorimotor functions, focuses on three areas: 1) perinatal factors influencing nociception in adult rats were examined in rats with hippocampal lesions, after the administration of stress influencing and psychostimulant drugs (dexamethasone, indomethacine and methamphetamine); 2) the effect of pre- and early postnatal methamphetamine administration was shown to impair the development of sensorimotor functions tested in rat pups throughout the preweaning period; 3) the effect of extensive dorsal rhizotomy of the brachial plexus during the early postnatal period was studied with respect to neuropathic pain development and sensorimotor functions. The present study indicates that prenatal or neonatal stress, as well as various drugs, may disturb the development of the nociceptive system and cause long-term behavioral changes persisting to adulthood and that some types of neuropathic pain cannot be induced during the first two postnatal weeks at all. A mature nervous system is required for the development of the described pathological behaviors., R. Rokyta, A. Yamamotová, R. Šlamberová, M. Franěk, Š. Vaculín, L. Hrubá, B. Schutová, M. Pometlová., and Obsahuje bibliografii a bibliografické odkazy
Since close relationship was shown between drug addiction and memory formation, the aim of the present study was to investigate the effects of interaction between prenatal methamphetamine (MA) exposure and MA treatment in adulthood on spatial and non-spatial memory and on the structure of the N-methyl-D-aspartate (NMDA) receptors in the hippocampus. Adult male rats prenatally exposed to MA (5 mg/kg) or saline were tested in adulthood. Non-spatial memory was examined in the Object Recognition Test (ORT) and spatial memory in the Object Location Test (OLT) and in the Memory Retention Test (MRT) conducted in the Morris Water Maze (MWM), respectively. Based on the type of the memory test animals were injected either acutely (ORT, OLT) or long-term (MWM) with MA (1 mg/kg). After each testing, animals were sacrificed and brains were removed. The hippocampus was then examined in Western Blot analysis for occurrence of different NMDA receptors’ subtypes. Our results demonstrated that prenatal MA exposure affects the development of the NMDA receptors in the hippocampus that might correspond with improvement of spatial memory tested in adulthood in the MWM. On the other hand, the effect of prenatal MA exposure on nonspatial memory examined in the ORT was the opposite. In addition, we showed that the effect of MA administration in adulthood on NMDA receptors is influenced by prenatal MA exposure, which seems to correlate with the spatial memory examined in the OLT., R. Šlamberová, M. Vrajová, B. Schutová, M. Mertlová, E. Macúchová, K. Nohejlová, L. Hrubá, J. Puskarčíková, V. bubeníková-Valešová, A. Yamamotová., and Obsahuje bibliografii
Bronzové klepadlo ve tvaru mušle, z níž vyrůstají akantové listy, v nich asymetricky dva mořští koňové. Na jejich předních nohách stojí nahý Nepun (vousy), v pravé ruce drží trojzubec., Chlíbec 2006#, č. 50., and Pochází ze sbírky R. Morawetze. Jedná se o velmi oblíbený typ známý jako "Quos ego", podle příslušného pasáže ve Vergiliově Aeneidě (1, 131-156), kterou zobrazení ilustruje. Existuje mnoho replik a variant z dílny A. Vittoria, ale i bronzů vytvořených podle jeho předlohy od poloviny 16. až do poloviny 17. století ( nejblíž je exemplář v The Walters Art Museum z let 1575-1585.
The possible protective action of pramiracetam, a pyrrolidinone nootropic drug, against hypobaric hypoxia was studied in two age groups of immature rats with implanted electrodes. Epileptic afterdischarges induced by hippocampal stimulation were used as a measure of hypoxic damage. Pramiracetam did not substantially change these afterdischarges in 12- and 18-day-old rat pups which were not exposed to hypoxia. Hypobaric hypoxia (simulated altitude of 7000 m for one hour) led to prolongation of the first afterdischarge in both age groups. Pramiracetam did not influence this prolongation in 12-day-old rats. The first afterdischarge was shortened significantly in 18-day-old animals but not to the level of rats not exposed to hypoxia. The afterdischarges elicited by repeated stimulations (four times at 10 min intervals) did not differ in pramiracetam-treatcd and control rats.