Prolonged cultivation of separated rat lung mast cells (LMC) in vitro is necessary to better investigate a possible role of LMC in different stages of tissue remodeling induced by hypoxia. Rat lung mast cells (LMC) were sepa rated using a protocol including an improved proteolytic extracti on and two subsequent density gradient separations on Ficoll-P aque PLUS and a new generation of Percoll, i.e. Percoll PLUS. Instead of usual isotonic stock Percoll solution, an alternative “asymptotically isotonic” stock solution was more successful in our density separation of LMC on Percoll PLUS. Separated cells were cultivated for six days in media including stem cell factor, interleu kins IL-3 and IL-6, and one of two alternative mixtures of antibi otics. These cultivations were performed without any contaminatio n and with only rare changes in cell size and morphology. Model co-cultivation of two allogenic fractions of LMC often caused considerable rapid changes in cell morphology and size. In contrast to these observations no or rare morphological changes were found after cultivation under hypoxic conditions. In conclusions, we modified separation on Percoll PLUS to be widely used, altered LMC separation with respect to purposes of long-lasti ng cultivation and observed some model morphological changes of LMC., J. Kubrycht ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
The founder of physiology studies in the Balkans and the pioneer of research on hypothermia, Ivan Djaja (Jean Giaja) was born 1884 in L’Havre. Giaja gained his PhD at the Sorbonne in 1909. In 1910 he established the first Chair of Physiology in the Balkans and organized the first Serbian In stitute for Physiology at the School of Philosophy of the University of Belgrade. He led this Institute for more than 40 subsequent years. His most notable papers were in the field of thermoregulation and bioenergetics. Djaja became member of the Serbian and Croatian academies of science and doctor honoris causa of Sorbonne. In 1952 for the seminal work on the behavior of deep cooled warm blooded animals he became associate member of the National Medical Academy in Paris. In 1955 the French Academy of Sciences elected him as associate member in place of deceased Sir Alexander Fleming. Djaja died in 1957 during a congress held in his honor. He left more than 200 scientific and other papers and the golden DaVincian credo “Nulla dies sine experimento”. His legacy was continued by several generations of researchers, the most prominent among them being Stefan Gelineo, Radoslav Andjus and Vojislav Petrović ., P. R. Andjus, S. S: Stojilkovic, G. Cvijic., and Obsahuje bibliografii a bibliografické odkazy
We have tested the hypothesis that neurons of both the ventral reticular nucleus and the adjacent parts of the lateral tegmental field (LTF) may be important for the production of motor programs associated with cough, expiration and aspiration reflexes. Our studies were conducted on non-decerebrate, spontaneously breathing cats under pentobarbitone anesthesia. Dysfunction of the medullary LTF region above the obex, produced by uni- or bilateral injections of kainic acid (a neurotoxin), regularly abolished the cough reflex evoked by mechanical stimulation of both the tracheobronchial and laryngeal regions and in most cases also the expiration reflex induced from the glottal area. However, some electrical activity still occurred in the neurogram of the recurrent laryngeal nerve during probing the laryngeal and glottal regions. Interestingly, the aspiration reflex elicited from the nasopharynx regularly persisted, although with lower intensity after the LTF lesion. Nevertheless, successive midcollicular decerebration performed in four cats also abolished the aspiration reflex. These experiments demonstrate the importance of medullary LTF neurons for the normal occurrence of cough and expiration reflexes. One possible explanation for the elimination of these expulsive processes is that the blockade of the LTF neurons may remove an important source of a facilitatory input to the brainstem circuitries that mediate cough and expiration reflexes. In addition, the potential importance of the mesencephalic reticular formation for the occurrence of the aspiration reflex and the role of the LTF in modulating both the eupnoeic breathing and the blood pressure are also discussed., J. Jakuš, A. Stránsky, I. Poliaček, H. Baráni, Ľ. Bošeľová., and Obsahuje bibliografii
Regulatory volume decrease (RVD) is essential for the survival of animal cells. The aim of this study was to observe the RVD process in rat ventricular myocytes, and to determine if the KATP channels are involved in the RVD process in these cells. By using reverse transcriptase polymerase chain reaction and Western blot analysis, we demonstrated that there are two types of KATP channels expressed in rat ventricular myocytes: Kir6.1 and Kir6.2. When rat cardiac myocytes were exposed to hypotonic solution, cell volume increased significantly within 15 min and then gradually recovered. This typical RVD process could be inhibited by a Cl– channel blocker (0.5 mM 9-anthracene-carboxylic acid , 9-AC), a K+ channel blocker (5.0 mM CsCl) and a KATP channel blocker glibenclamide (10 μM). Electrophysiological results showed that hypotonic solution activated a whole-cell current, which had similar biophysical characteristics with KATP opener (pinacidil)-induced currents. This current could be blocked by glibenclamide. Our data suggested that the RVD process in rat ventricular myocytes is dependent on the activation of K+ channels, and that KATP channels are involved in this process., L. Shi ... [et al.]., and Obsahuje seznam literatury
Measurements of ryanodine receptor (RyR) activity during dynamic changes of calcium concentration have suggested that RyR has at least four calcium binding sites, and that activation transpires as an increase in the activity within the high open probability H-mode. Binding of several Ca2+ ions within the H-mode should manifest itself in the steady-state RyR activity by the presence of multiple closed times. However, previously only two closed times were detected in the H-mode of RyR activity. Here we recorded steady-state activity of single cardiac RyRs with high temporal resolution and compared it to data simulated under the same conditions using our previously published model of RyR gating. At a 10 kHz resolution, the closed time histograms of both experimental and simulated data had three exponential components. The closed times of simulated data were not significantly different from those obtained experimentally. After filtering at 2 kHz, only two exponential closed time components with time constants not significantly different from those previously published could be detected in both experimental and simulated records. The conformity of the steady-state experimental data to the model derived from the dynamic data provides further support for the idea that RyRs need binding of multiple Ca2+ ions to open., M. Dura, I. Zahradník, A. Zahradníková., and Obsahuje bibliografii
MK-801 impaired social recognition potency of adult male rats when given immediately after the initial interaction with a juvenile rat. Administration of kynurenic acid prior to the initial interaction protected the adults against recognition deficits induced by MK-801. When re-exposed at a delay of 30 min to the familiar juvenile, social investigation in the adults was significantly reduced. Thus, the adults are able to remember olfactory stimuli emitted by juvenile con-specifics., Z. Hliňák, I. Krejčí., and Obsahuje bibliografii
Chronic hypoxia induces an increased production of nitric oxide (NO) in pulmonary prealveolar arterioles. Bioavailability of the NO in the pulmonary vessels correlates with concentration of L-arginine as well as ac tivity of phosphodiesterase-5 enzyme (PDE- 5). We tested a hypothesis whet her a combination of L-arginine and PDE-5 inhibitor sildenafil has an additive effect in reduction of the hypoxic pulmonary hypertension (HPH) in rats. Animals were exposed to chronic normobaric hypoxia for 3 weeks. In the AH group, rats were administered L-arginine during chronic hypoxic exposure. In the SH group, rats were administered sildenafil during chronic hypoxic exposure. In the SAH group, rats were treated by the combination of L-arginine as well as sildenafil during exposure to chronic hypoxia. Mean PAP, structural remodeling of peripheral pu lmonary arterioles (%DL) and RV/LV+S ratio was significantl y decreased in the SAH group compared to hypoxic controls even decreased compared to the AH and the SH groups in first two measured parameters. Plasmatic concentration of cGMP and NOx were significantly lower in the SAH group compared to hypoxic controls. We demonstrate that NO synthase substrate L-arginine and phosphodiesterase-5 inhibitor sildenafil administered in combination are more potent in attenuation of the HPH compared to a treatment by substances given alone., H. Al-Hiti ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy