Glutamate is a well-characterized excitatory neurotransmitter in the central nervous system (CNS). Recently, glutamate receptors (GluRs) were also found in peripheral tissues, including the heart. However, the function of GluRs in peripheral organs remains poorly understood. In the present study, we found that N-methyl-D-aspartate (NMDA) could increase intracellular calcium ([Ca2+]i) level in a dose-dependent manner in cultured neonatal rat cardiomyocytes. NMDA at 10-4 M increased the levels of reactive oxygen species (ROS), cytosolic cytochrome c (cyto c), and 17-kDa caspase-3, but depolarized mitochondrial membrane potential, leading to cardiomyocyte apoptosis. In addition, NMDA treatment induced an increase in ba x mRNA but a decrease in bcl-2 mRNA expression in the cardiomyocytes. The above effects of NMDA were bloc ked by the NMDA receptor antagonist (+)-5-methyl- 10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801), and by ROS scavengers glutathione (GSH) and N-acetylcystein (NAC). These results suggest that stimulation of NMDA receptor in the cardiomyocyte may lead to apoptosis via a Ca2+, ROS, and caspase-3 mediated pathway. These findings suggest that NMDA receptor may play an important role in myocardial pathogenesis., X. Gao, X. Xu, J. Pang, C. Zhang, J. M. Ding, X. Peng, Y. Liu, J.-M. Cao., and Obsahuje bibliografii a bibliografické odkazy
• NO concentration was measured in the periendothelial area of the femoral artery by Malinski’s porphyrinic • NO sensor in seven anaesthetized dogs. The basal concentration was 154.2 ±5.6 nM and two-minute intraarterial infusions of acetylcholine (3-4 /tg/ml/min) or bradykinin (30 - 40 ng/ml/min) increased this value significantly to 204.3±16.4 and 266.5±16.4 nM (P<0.01), respectively. Inhibition of »NO synthase by L-NAME (50 mg/kg) declined the basal • NO concentration only to 137.2±3.3 nM (PcO.Ol). Subsequent administration of acetylcholine and bradykinin attenuated significantly the increase in • NO concentration. Surprisingly, both agonists still induced a significant increase of *NO concentration by 125.3±8.3 and 156.6±26.9 nM, respectively (PcO.Ol). One of the possible explanations may be that besides arginine-citrulline plus the • NO pathway other sources of • NO could be involved in the high level of • NO after • NO synthase blockade by L-NAME.
During five years (1992–1996) the effect of age of collared flycatcher males on arrival time, quality of nest site, partial losses, feeding effort and reproduction were examined in the primaeval, mature (170–250 year old) oak-lime-hornbeam forest of Białowieża National Park. The males were divided into two age groups: males with brown primaries and wing covers were aged as young, and males whose wings were uniformly black were aged as old ones. Only the arrival date and the clutch size were significantly different between the groups of males but other breeding features were very similar. These results may be explained by a short life-span of flycatchers and by conditions in the Białowieża National Park. A surplus of good natural cavities reduced competition between young and old males, and a surplus of food could reduce differences in foraging abilities. A high predation rate was the main cause of nesting losses. In such conditions, the strategy to take each opportunity of reproduction may lead to high life time reproduction success and can reduce potential differences in breeding success young and old males.
Profesor James Watson Cronin navštívil na konci srpna Českou republiku už potřetí, tentokrát byl pozván přednášet na prestižní Evropské škole vysokoenergetické fyziky, která se letos konala v Třešti. Dále navštívil optickou dílnu Společné laboratoře Univerzity Palackého a Fyzikálního ústavu Akademie věd v Olomouci, kde se vyrábějí zrcadla pro fluorescenční teleskopy projektu Pierre Auger v Argentině. Jeho návštěvy souvisejí s dokončováním výstavby této obří mezinárodní observatoře pro výzkum kosmického záření rekordních energií, na jejímž budování v argentinské pampě a vědeckém provozu se podílí 16 států včetně České republiky. Objasnění původu tohoto záření o energiích až 10milionkrát vyšších, než kolik dokáží fyzikové docílit v nákladných pozemních urychlovačích, patří mezi nejtěžší nerozluštěné otázky soudobé fyziky i astronomie. and Martina Boháčová.
Ignored Nobelist. The Nobel Prize in Physiology or Medicine 2010 was awarded to Robert. G. Edwards "for the development of in vitro fertilization" (IVF). The historic, technical and ethical aspects of IVF are discussed.
The Nobel prize in physics was in 2013 awarded to Belgian theorist François Englert and English theorist Peter W. Higgs "for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles, and which recently was confirmed through the discovery of the predicted fundamental particle, by the ATLAS and CMS experiments at CERN´s Large Hadron Collider"., Tomáš Blažek., and Obsahuje bibliografii