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1452. Action of GABA-B antagonist on cortical epileptic afterdischarges in rats is similar to that of GABA-A antagonist
- Creator:
- Živanović, D., Klára Bernášková, Kaminskij, Yu., and Pavel Mareš
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, epileptické záchvaty, mozková kůra, epileptic seizures, cerebral cortex, rat, CGP 35348, bicuculline, 14, and 612
- Language:
- English
- Description:
- Threshold intensities for epileptic phenomena induced by cortical stimulation were used for comparison of the action of GABA-B and GABA-A antagonists in rats with implanted electrodes. Both CGP 35348 (200 mg/kg i.p.) and bicuculline (4 mg/kg i.p.) significantly decreased thresholds for spike-and-wave afterdischarges and their motor counterpart (clonic seizures) whilst transition into the second, limbic type of afterdischarge as well as threshold for movements directly bound to stimulation remained uninfluenced by either drug., D. Živanović, K. Bernášková, Yu. Kaminskij, P. Mareš., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1453. Action of granulopoiesis-stimulating cytokines rhG-CSF, rhGM-CSF, and rmGM-CSF on murine hematopoietic progenitor cells for granulocytes and macrophages (GM-CFC).
- Creator:
- Hofer, M., Vacek, A., and Weiterová, L.
- Type:
- article, model:article, and TEXT
- Subject:
- Murine hematopoiesis, GM-CFC, rhGM-CSF, and rmGM-CSF
- Language:
- English
- Description:
- The aim of this study was to provide new data to the knowledge of mechanisms by which recombinant human granulocyte colony-stimulating factor (rhG-CSF), recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) and recombinant murine granulocyte macrophage colony-stimulating factor (rmGM-CSF) enhance the numbers of colonies growing from hematopoietic progenitor cells for granulocytes and macrophages (GM-CFC) in the murine bone marrow. The in vitro technique for cultivating GM-CFC from normal bone marrow cells was used. For evaluation of stimulatory actions of the drugs studied, the factors themselves or sera of mice given these factors were added to the cultures. The factors or the sera were present in the cultures either as the only potentially stimulatory agents or acted jointly with a suboptimum concentration of recombinant murine interleukin-3 (rmIL-3). It was found that both rhG-CSF and rmGM-CSF stimulate the proliferatio n of GM-CFC by a combination of direct mechanisms (direct actions on the target cells) and indirect effects (effects mediated through the induction of other cytokines and/or growth factors in the murine organism). The rhGM-CSF exhibited somewhat weaker in vitro effects in comparison with the other two factors and only indirect effects were noted. Additional in vivo experiments documented that, in spite of differences in mechanisms of action of the individual drugs studied on murine bone marrow cells in vitro, equal in vivo doses of the factors induce quantitatively similar effects on the production of GM-CFC in vivo.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1454. Action of Two Neuroactive Steroids Against Motor Seizures Induced by Pentetrazol in Rats During Ontogeny
- Creator:
- Mareš, P., Haugvicová, R., and Kasal, A.
- Type:
- article, model:article, and TEXT
- Subject:
- Convulsion, Rat, Development, Pregnanolone, New neuroactive steroid, Anticonvulsant action, and Time course of action
- Language:
- English
- Description:
- The anticonvulsant action of two neuroactive steroids, 3α–hydroxy-5β–pregnan-20-one (pregnanolone) and triethylammonium 3α–hydroxy-20-oxo-5α–pregnan-21-yl hydrogensuccinate (THDOC-conjugate), was tested against motor seizures induced by pentetrazol in immature rats. Five age groups (7, 12, 18 and 25 days old and adult rats) were pretreated with the steroids in doses from 2.5 to 40 mg/kg i.p. Twenty minutes later pentetrazol (100 mg/kg s.c.) was administered. Minimal seizures (clonic seizures of head and forelimb muscles with preserved righting ability) could be induced in the three older age groups. They were suppressed by pregnanolone in all these tested groups (this effect was best expressed in 18-day-old rats and decreased with age), whereas significant changes in THDOC-conjugate-pretreated animals appeared only in 18-day-old rats. Generalized tonic-clonic seizures were suppressed by both neuroactive steroids in all age groups, this effect being more marked with pregnanolone and again decreased with age. The 7- and 12-day-old rats exhibited higher sensitivity of the tonic phase so that generalized clonic seizures were observed. Duration of the effect was studied in 12- and 25-day-old animals; it was substantially shorter in the older rats than in 12-day-old animals. Both drugs exhibited an anticonvulsant action in developing rats but, unfortunately, their effect was only shortlasting.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1455. Actions of angiotensin II and dopamine in the medial preoptic area on prolactin secretion
- Creator:
- Leite, C. M., Machado, G. J. R., Dornelles, R. C. M., and Franci, Celso Rodrigues
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, dopamin, estrogeny, physiology, dopamine, estrogens, prolactin, medial preoptic area, angiotensin II, dopaminergic antagonists, 14, and 612
- Language:
- English
- Description:
- Dopamine (DA) is known as a primary regulator of prolactin secretion (PRL) and angiotensin II (Ang II) has been recognized as one brain inhibitory factor of this secretion. In this work, estrogen-primed or unprimed ovariectomized rats were submitted to the microinjection of saline or Ang II after previous microinjection of saline or of DA antagonist (haloperidol, sulpiride or SCH) both in the medial preoptic area (MPOA). Our study of these interactions has shown that 1) estrogen-induced PRL secretion is mediated by Ang II and DA actions in the MPOA, i.e. very high plasma PRL would be prevented by inhibitory action of Ang II, while very low levels would be prevented in part by stimulatory action of DA through D2 receptors, 2) the inhibitory action of Ang II depends on estrogen and is mediated in part by inhibitory action of DA through D1 receptors and in other part by inhibition of stimulatory action of DA through D2 receptors., C. M. Leite, G. J. R. Machado, R. C. M. Dornelles, C. R. Franci., and Obsahuje bibliografii a bibliografické poznámky
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1456. Actions of lyotropic anions on the mechanical properties of fast and slow twitch rat muscles at different temperatures
- Creator:
- Wondmikun, Y., Tomáš Soukup, and Gerhard Asmussen
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, svaly, teplota, muscles, temperature, slow and fast muscles, contractile properties, twitch potentiation, lyotropic anions, rat, 14, and 612
- Language:
- English
- Description:
- The effects of lyotropic (swelling) anions (Cl-, Br-, NO3- and I-) on contractile properties of fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus (SOL) muscles were investigated in vitro at 20 °C and 35 °C. Isolated muscles bathed in anionic Tyrode solution were stimulated directly and isometric single twitches and fused tetanic contractions were recorded. In a Cl- Tyrode solution a decrease of the bathing temperature led to a cold potentiation of the twitch tension (Pt) in EDL muscles, however, to a cold depression in SOL muscles, in both muscles combined with a prolongation of contraction (CT) and half relaxation (HRT) times. The extent and order of the potentiating effect of lyotropic anions on the Pt, CT and HRT in EDL and SOL were quite similar and increased in the order: Cl-< Br- < NO3- < I-. Since the lyotropic anions did not influence tetanic tensions, the twitch-tetanus ratio (TTR) was increased in NO3- and I- solutions. All effects of the anions were rapidly and completely reversed in both muscles when the test solution was replaced by the normal one. The temperature decrease caused no significant alteration in the potentiation capacity of the anions or in the kinetics of their action and reversibility., Y. Wondmikun, T. Soukup, G. Asmussen., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1457. Activation and Modulation of Ligand-Gated Ion Channels
- Creator:
- Krůšek, J., Dittert, I., Hendrych, T., Hník, P., Horák, M., Petrovic, M., Sedláček, M., Sušánková, K., Svobodová, L., Toušová, K., Ujec, E., Vlachová, V., Vyklický, L., Vyskočil, F., and Vyklický jr., L.
- Type:
- article, model:article, and TEXT
- Subject:
- Acetylcholine receptor, GABA receptor, gluatmate receptor, NMDA receptor, Vanilloid receptor, TRP receptor, and Ionic channel
- Language:
- English
- Description:
- Ligand-gated ionic channels are integral membrane proteins that enable rapid and selective ion fluxes across biological membranes. In excitable cells, their role is crucial for generation and propagation of electrical signals. This survey describes recent results from studies performed in the Department of Cellular Neurophysiology, Institute of Physiology ASCR, aimed at exploring the conformational dynamics of the acetylcholine, glutamate and vanilloid receptors during their activation, inactivation and desensitization. Distinct families of ion channels were selected to illustrate a rich complexity of the functional states and conformational transitions these proteins undergo. Particular attention is focused on structure-function studies and allosteric modulation of their activity. Comprehension of the fundamental principles of mechanisms involved in the operation of ligand-gated ion channels at the cellular and molecular level is an essential prerequisite for gaining an insight into the pathogenesis of many psychiatric and neurological disorders and for efficient development of novel specifically targeted drugs.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1458. Activation of adenosine A3 receptors potentiates stimulatory effects of IL-3, SCF, and GM-CSF on mouse granulocyte-macrophage hematopoietic progenitor cells
- Creator:
- Michal Hofer, Antonín Vacek, Milan Pospíšil, Jiřina Holá, Denisa Štreitová, and Vladimír Znojil
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, biofyzika, krvetvorba, růstové faktory, biophysics, hematopoiesis, growth factors, adenosine A3 receptor, IB-MECA, hematopoietic growth factors, 14, and 612
- Language:
- English
- Description:
- Adenosine A3 receptor agonist N6-(3-iodobenzyl)adenosine-5’-N-methyluronamide (IB-MECA) has been tested from the point of view of potentiating the effects of hematopoietic growth factors interleukin-3 (IL-3), stem cell factor (SCF), granulocyte- macrophage colony-stimulating factor (GM-CSF), and granulocyte colony-stimulating factor (G-CSF) on the growth of hematopoietic progenitor cells for granulocytes and macrophages (GM-CFC) in suspension of normal mouse bone marrow cells in vitro. IB-MECA alone induced no GM-CFC growth. Significant elevation of numbers of GM-CFC evoked by the combinations of IB-MECA with IL-3, SCF, or GM-CSF as compared with these growth factors alone has been noted. Combinat ion of IB-MECA with G-CSF did not induce significantly higher numbers of GM-CFC in comparison with G-CSF alone. Joint action of three drugs, namely of IB-MECA + IL-3 + GM-CSF, produced significantly higher numbers of GM-CFC in comparison with the combinations of IB-MECA + IL-3, IB-MECA + GM-CSF, or IL-3 + GM-CSF. These results give evidence of a significant role of selective activation of adenosine A3 receptors in stimulation of the growth of granulocyte/macrophage hematopoietic progenitor cells., M. Hofer ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1459. Activation of adenylate cyclase system in the preconditioned rat heart
- Creator:
- Ľudmila Okruhlicová, Ravingerová, T., Dezider Pancza, Narcisa Tribulová, Ján Styk, and Štetka, R.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, cytochemie, srdce, cytochemistry, heart, ischemic preconditioning, adenylate cyclase, rat, 14, and 612
- Language:
- English
- Description:
- Ischemic preconditioning (IP) protects the heart against subsequent prolonged ischemia. Whether the β-adrenoceptor/adenylate cyclase pathway contributes to this cardioprotection is not yet fully known. Using enzyme catalytic cytochemistry we studied the adenylate cyclase activity and its distribution in the preconditioned rat heart. Adenylate cyclase activity was examined in Langendorff-perfused rat hearts subjected to the following conditions: control perfusion; 30 min regional ischemia; 5 min occlusion and 10 min reperfusion (IP); IP followed by ischemia. Ischemia-induced arrhythmias and the effect of ischemic preconditioning on the incidence of arrhythmias were analyzed. At the end of experiment the heart was shortly prefixed with glutaraldehyde. Tissue samples from the left ventricle were incubated in a medium containing the specific substate AMP-PNP for adenylate cyclase and then routinely processed for electron microscopy. Adenylate cyclase activity was cytochemically demonstrated in the sarcolemma and the junctional sarcoplasmic reliculum (JSR) in control hearts, while it was absent after test ischemia. The highest activity of the precipitate was observed after ischemic preconditioning. In the preconditioned hearts followed by test ischemia, adenylate cyclase activity in the precipitate was preserved in sarcolemma and even more in JSR. Protective effect of ischemic preconditioning was manifested by the suppression of severe arrhythmias. These rresults indicate the involvement of the adenylate cyclase system in mechanisms underlying ischemic preconditioning., Ľ. Okruhlicová, T. Ravingerová, D. Pancza, N. Tribulová, J. Styk, R. Štetka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1460. Activation of fat body in Periplaneta americana (Blattoptera: Blattidae) by hypertrehalosemic hormones (HTH): New insights into the mechanism of cell signalling
- Creator:
- Steele, John E.
- Format:
- print, text, and regular print
- Type:
- article, bibliography, model:article, and TEXT
- Subject:
- zoologie, entomologie, hmyz, Blattoptera, Blattidae, Periplaneta americana, hemolymfa, trehalosa, biosyntéza, kontrola biosyntézy, hypertrehalosemické hormony, mechanismus účinku, 595.2/.7, and 591.1
- Language:
- English
- Description:
- In cockroaches and certain other insects the concentration of trehalose in the hemolymph is increased by hypertrehalosemic hormone (HTH), a neuropeptide originating in the corpus cardiacum. A vital step in the action of HTH to promote conversion of glycogen stored in the fat body to trehalose is the activation of phosphorylase. The means by which HTH activates phosphorylase, with particular emphasis on its role in the regulation of intracellular calcium, is discussed. Additional information supporting the view that HTH stimulated synthesis of trehalose, and possibly its release from the trophocyte, is regulated by fatty acids and eicosanoids is presented., John E. Steele, and Lit
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public