Bronchodilator aminophylline may induce atrial or less often ventricular arrhythmias. The mechanism of this proarrhythmic side effect has not been fully explained. Modifications of inward rectifier potassium (Kir) currents including IK1 are known to play an important role in arrhythmogenesis; however, no data on the aminophylline effect on these currents have been published. Hence, we tested the effect of aminophylline (3-100 µM) on IK1 in enzymatically isolated rat ventricular myocytes using the whole-cell patch-clamp technique. A dual steady-state effect of aminophylline was observed; either inhibition or activation was apparent in individual cells during the application of aminophylline at a given concentration. The smaller the magnitude of the control IK1, the more likely the activation of the current by aminophylline and vice versa. The effect was reversible; the relative changes at -50 and -110 mV did not differ. Using IK1 channel population model, the dual effect was explained by the interaction of aminophylline with two different channel populations, the first one being inhibited and the second one being activated. Considering various fractions of these two channel populations in individual cells, varying effects observed in the measured cells could be simulated. We propose that the dual aminophylline effect may be related to the direct and indirect effect of the drug on various Kir2.x subunits forming the homo- and heterotetrameric IK1 channels in a single cell. The observed IK1 changes induced by clinically relevant concentrations of aminophylline might contribute to arrhythmogenesis related to the use of this bronchodilator in clinical medicine.

• Klíčová slova
• Aminophylline, Arrhythmia, Dual effect, Fibrillation, Inward rectifier, Population channel model,
• MeSH
• aminofylin škodlivé účinky   MeSH
• bronchodilatancia škodlivé účinky   MeSH
• draslík farmakologie   MeSH
• draslíkové kanály dovnitř usměrňující * MeSH
• kardiomyocyty fyziologie   MeSH
• krysa rodu Rattus MeSH
• srdeční arytmie MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminofylin MeSH
• bronchodilatancia MeSH
• draslík MeSH
• draslíkové kanály dovnitř usměrňující * MeSH

In this study, we focused on age-related changes in astrocyte functioning, predominantly on the ability of astrocytes to regulate their volume in response to a pathological stimulus, namely extracellular 50 mM K+ concentration. The aim of our project was to identify changes in the expression and function of transport proteins in the astrocytic membrane and properties of the extracellular space, triggered by aging. We used three-dimensional confocal morphometry, gene expression profiling, immunohistochemical analysis, and diffusion measurement in the hippocampal slices from 3-, 9-, 12-, and 18-month-old mice, in which astrocytes are visualized by enhanced green fluorescent protein under the control of the promoter for human glial fibrillary acidic protein. Combining a pharmacological approach and the quantification of astrocyte volume changes evoked by hyperkalemia, we found that marked diversity in the extent of astrocyte swelling in the hippocampus during aging is due to the gradually declining participation of Na+-K+-Cl- transporters, glutamate transporters (glutamate aspartate transporter and glutamate transporter 1), and volume-regulated anion channels. Interestingly, there was a redistribution of Na+-K+-Cl- cotransporter and glutamate transporters from astrocytic soma to processes. In addition, immunohistochemical analysis confirmed an age-dependent decrease in the content of Na+-K+-Cl- cotransporter in astrocytes. The overall extracellular volume changes revealed a similar age-dependent diversity during hyperkalemia as observed in astrocytes. In addition, the recovery of the extracellular space was markedly impaired in aged animals.

• Klíčová slova
• Aging, Astrocyte, Hippocampus, Potassium/glutamate uptake, Volume regulation,
• MeSH
• astrocyty účinky léků   metabolismus   patologie   fyziologie   MeSH
• draslík farmakologie   MeSH
• gliový fibrilární kyselý protein MeSH
• hipokampus cytologie   MeSH
• myši transgenní MeSH
• stárnutí patologie   fyziologie   MeSH
• velikost buňky * MeSH
• zelené fluorescenční proteiny MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• gliový fibrilární kyselý protein MeSH
• zelené fluorescenční proteiny MeSH

The effect of potassium (K) concentration gradient on stable caesium (Cs) uptake by Calla palustris was studied under hydroponic conditions after eight-day exposure in a greenhouse experiment. The plants were exposed to two different concentrations of Cs (provided as 0.5 and 1 mM CsCl) and five different concentrations of K (provided as K2SO4 in 0.5, 1, 2, 5, and 10 mM). The results indicate negative dependence of Cs uptake on K concentrations for both Cs treatments. The application of K reduced the transfer of stable Cs from water to plant by about 44-72% for 0.5 mM CsCl and 56-74% for 1 mM CsCl. The highest efficiency of Cs removal from water was observed for plants in K+ deficient solutions (plants starving), with an efficiency 8.0% for plants cultivated in 0.5 mM CsCl and 9.4% for plants in 1 mM CsCl. An increasing concentration of K also supported translocation of Cs from roots to leaves. Higher translocation was observed for the treatments with lower level of Cs, where the concentration of Cs in leaves became higher than that in roots. The Cs uptake and translocations were affected not only by the external concentration of K, but also the external concentration of stable Cs. A high concentration of K in the environment protects the food chain from Cs uptake by plants, but lowers the efficiency of phytoremediation techniques.

• Klíčová slova
• Caesium, Calla palustris, Phytoremediation, Potassium, Uptake,
• MeSH
• biodegradace MeSH
• biologický transport účinky léků   fyziologie   MeSH
• Calla (rostlina) metabolismus   MeSH
• cesium analýza   metabolismus   MeSH
• chloridy analýza   metabolismus   MeSH
• draslík metabolismus   farmakologie   MeSH
• kořeny rostlin chemie   metabolismus   MeSH
• listy rostlin chemie   metabolismus   MeSH
• radioaktivní látky znečišťující půdu MeSH
• radioizotopy cesia analýza   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cesium chloride MeSH Prohlížeč
• cesium MeSH
• chloridy MeSH
• draslík MeSH
• radioaktivní látky znečišťující půdu MeSH
• radioizotopy cesia MeSH

The uptake of stable cesium (133Cs) by Calla palustris was evaluated from four different substrates: water, soil, keramzit (a clay granule) and water with the addition of a potassium compound, after an eight days exposure to a solution of 0.5mM cesium chloride. Stable cesium was used because it is commonly supposed that its uptake by plants is the same of that of radiocesium (137Cs). The plants were differentiated in their parts (roots, healthy leaves, dead leaves and flowers) and analyzed with ICP-MS. The lowest average concentration of absorbed Cs was found in plants exposed in soil (0.7mg/kg, S.D.=96.8), while the highest in plants exposed in water (147mg/kg, S.D.=51.7). During the experiment the water planted plants removed 31.6% of provided Cs while those planted in soil removed only 0.06%. The addition of potassium to water was tested because of the competition effect that arises between these two elements: this effect was confirmed with the result that the average uptake in the presence of potassium was lower (41mg/kg in exposed plants, S.D.=76.1). The uptake was also lower in the solid-based substrates (soil and keramzit), because of the known tendency of Cs to bind with soil particles, thus becoming less available to plants. There was no evidence that the different parts of the plant showed different uptake effectiveness, or that the health of the plant (evaluated with a qualitative method) had any effect on the uptake of Cs.

• Klíčová slova
• (133)Cs, Calla palustris, Phytoremediation, Radiocesium, Stable cesium, Uptake,
• MeSH
• biodegradace MeSH
• Calla (rostlina) metabolismus   MeSH
• cesium metabolismus   farmakologie   MeSH
• chloridy farmakologie   MeSH
• draslík metabolismus   farmakologie   MeSH
• kořeny rostlin metabolismus   MeSH
• látky znečišťující životní prostředí metabolismus   MeSH
• minerály MeSH
• nadzemní části rostlin metabolismus   MeSH
• půda MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cesium chloride MeSH Prohlížeč
• cesium MeSH
• chloridy MeSH
• draslík MeSH
• keramzit MeSH Prohlížeč
• látky znečišťující životní prostředí MeSH
• minerály MeSH
• půda MeSH
• voda MeSH

We investigated fungal growth and community composition in buried meshbags, amended with apatite, biotite or hornblende, in Norway spruce (Picea abies) forests of varying nutrient status. Norway spruce needles and soil collected from forests overlying serpentinite had low levels of potassium and phosphorus, those from granite had low levels of magnesium, whereas those from amphibolite had comparably high levels of these nutrients. We assayed the fungal colonization of meshbags by measuring ergosterol content and fungal community with 454 sequencing of the internal transcribed spacer region. In addition, we measured fine root density. Fungal biomass was increased by apatite amendment across all plots and particularly on the K- and P-deficient serpentinite plots, whereas hornblende and biotite had no effect on fungal biomass on any plots. Fungal community (total fungal and ectomycorrhizal) composition was affected strongly by sampling location and soil depth, whereas mineral amendments had no effect on community composition. Fine root biomass was significantly correlated with fungal biomass. Ectomycorrhizal communities may respond to increased host-tree phosphorus demand by increased colonization of phosphorus-containing minerals, but this does not appear to translate to a shift in ectomycorrhizal community composition. This growth response to nutrient demand does not appear to exist for potassium or magnesium limitation.

• Klíčová slova
• Norway spruce (Picea abies), ectomycorrhizal fungi (EMF), ergosterol, fungal community composition, hyphae, minerals, soil nutrients,
• MeSH
• biomasa MeSH
• draslík farmakologie   MeSH
• ergosterol metabolismus   MeSH
• fosfor farmakologie   MeSH
• hořčík farmakologie   MeSH
• houby účinky léků   růst a vývoj   MeSH
• lesy * MeSH
• listy rostlin chemie   účinky léků   MeSH
• minerály metabolismus   MeSH
• multivariační analýza MeSH
• půdní mikrobiologie * MeSH
• smrk účinky léků   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• ergosterol MeSH
• fosfor MeSH
• hořčík MeSH
• minerály MeSH

The yeast Nha1p Na(+), K(+)/H(+) antiporter has a house-keeping role in pH and cation homeostasis. It is also needed to alleviate excess Na(+) or K(+) from the cytoplasm under high external concentrations of these cations. Erv14p, a putative cargo receptor for transmembrane proteins is required for trafficking of Nha1p from the endoplasmic reticulum to the plasma membrane. Sensitivity to high Na(+) concentrations of the erv14 mutant associated to the intracellular mislocalization of Nha1p-GFP, together with a lower Na(+) efflux, indicate the involvement of this mutual association to accomplish the survival of the yeast cell upon sodium stress. This observation is supported by the protein-protein interaction between Erv14p and Nha1p detected by the mating-based Split Ubiquitin System and co-immunoprecipitation assays. Our results indicate that even though Erv14p interacts with Nha1p through the TMD, the C-terminal is important not only for the efficient delivery of Nha1p to the plasma membrane but also for its dimerization to accomplish its role in yeast salt tolerance.

• Klíčová slova
• Erv14p, Mislocalization, Nha1p, Protein–protein interaction, Salt-tolerance, Yeast,
• MeSH
• biologický transport MeSH
• chlorid sodný metabolismus   farmakologie   MeSH
• draslík metabolismus   farmakologie   MeSH
• interakční proteinové domény a motivy MeSH
• kationty jednomocné MeSH
• membránové proteiny chemie   genetika   metabolismus   MeSH
• multimerizace proteinu MeSH
• Na(+)-H(+) antiport chemie   genetika   metabolismus   MeSH
• proteiny přenášející kationty chemie   genetika   metabolismus   MeSH
• protony * MeSH
• regulace genové exprese u hub * MeSH
• rekombinantní fúzní proteiny chemie   genetika   metabolismus   MeSH
• Saccharomyces cerevisiae - proteiny chemie   genetika   metabolismus   MeSH
• Saccharomyces cerevisiae účinky léků   genetika   metabolismus   MeSH
• sekundární struktura proteinů MeSH
• tolerance k soli MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorid sodný MeSH
• draslík MeSH
• Erv14 protein, S cerevisiae MeSH Prohlížeč
• kationty jednomocné MeSH
• membránové proteiny MeSH
• Na(+)-H(+) antiport MeSH
• NHA1 protein, S cerevisiae MeSH Prohlížeč
• proteiny přenášející kationty MeSH
• protony * MeSH
• rekombinantní fúzní proteiny MeSH
• Saccharomyces cerevisiae - proteiny MeSH

Little is known about the effects of nutrient availability on the growth of Trifolium medium in alkaline soil. In 2010, a pot experiment (10 N, P and K fertiliser treatments) with seeding of T. medium into alkaline soil was performed and emergence of seedlings, survival, aboveground and belowground organs were studied. The positive effects of increased nutrient availability on seedling emergence ranged from 5% in the control to 17% in the high P treatment. The lowest mortality was in treatments with P and K supply and the highest in treatments with N supply, due to the sensitivity of young plants to high N availability. The highest values of most measured aboveground plant traits were recorded in treatments with simultaneous application of N, P and K. There were highly positive effects of P supply alone or in combination with N and K on the development of belowground organs. Taproot length ranged from 11.5 in high N to 40.2 cm in P treatment. There was a negative effect of N application on nodulation, especially in N treatments, where growth of T. medium was limited by insufficient P supply. The number of nodules per plant ranged from 0.8 to 4.5 in the high N and P treatments. As demonstrated in this study, T. medium is a potentially suitable legume for alkaline soils. It requires a relatively high P and K supply as well as moderate mineral N supply to achieve its maximum growth potential.

• Klíčová slova
• Flowering, mineral nutrition, phenotypic plasticity, roots, zigzag clover,
• MeSH
• draslík farmakologie   MeSH
• dusík farmakologie   MeSH
• fosfor farmakologie   MeSH
• kořeny rostlin účinky léků   fyziologie   MeSH
• květy účinky léků   fyziologie   MeSH
• semenáček účinky léků   fyziologie   MeSH
• Trifolium účinky léků   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• dusík MeSH
• fosfor MeSH

The aim of this study was to investigate the response of Russian sturgeon (Acipenser gueldenstaedtii) sperm to external cations (Na(+), K(+), Ca(2+), and Mg(2+)) and their susceptibility on the induction of motility and swimming behavior. An in vitro spermatozoa motility assay was used by a computer-aided Motion-Analysis system. Sperm motility was inhibited by 60 mM NaCl (~140 mOsm/kg) and 0.7 mM KCl solutions (~ 21.4 mOsm/kg). The Ca(2+) and Mg(2+) ions were not able to inhibit spermatozoa motility. By contrast, Na(+) within a limited concentration range (between 45 and 55 mm) was able to reverse the inhibitory effect of K(+) at the critical concentration (0.7 mM). Ca(2+) and Mg(2+) were also able to reverse the K(+)-mediated spermatozoa motility restriction at concentrations starting at 0.01 and 0.1 mM, respectively. These results provide evidence for the role of K(+) in suppressing spermatozoa motility, and suggest that Ca(2+), Mg(2+), and possibly Na(+) trigger motility in Russian sturgeon sperm.

• MeSH
• analýza spermatu MeSH
• draslík farmakologie   MeSH
• hořčík farmakologie   MeSH
• kationty farmakologie   MeSH
• motilita spermií účinky léků   MeSH
• osmolární koncentrace MeSH
• plavání MeSH
• ryby * fyziologie   MeSH
• sodík farmakologie   MeSH
• spermie účinky léků   fyziologie   MeSH
• vápník farmakologie   MeSH
• vodní hospodářství MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• hořčík MeSH
• kationty MeSH
• sodík MeSH
• vápník MeSH

The present study shows the roles of osmolality, calcium (Ca(2+))-potassium (K(+)) antagonist and Ca(2+) in sperm activation and flagellar beating of a sturgeon species, sterlet (Acipenser ruthenus). Sperm motility was activated at hypoosmolality relative to seminal plasma and suppressed at 175 mOsmol kg(-1). Sperm activation was totally suppressed by 0.35mM K(+), but Ca(2+) could fully reverse K(+) inhibitory effect at Ca(2+): K(+) ratio of 0.25. Neither EGTA (a chelator of Ca(2+) ions) nor nifedipine (a Ca(2+) channel blocker) prevented sperm activation. But, sperm motility and velocity were significantly decreased by EGTA, nifedipine and an inhibitor for Ca(2+)/calmodulin activated phosphodiesterase (w-7) that suggest role of Ca(2+) signaling after triggering sperm activation through hypoosmolality. Symmetric flagellar beating was also turned to asymmetric after activation in w-7, which is an evidence for modulation of Ca(2+)-binding proteins activity. Sturgeon sperm, similar to salmonids, is immotile in seminal plasma due to high K(+) concentrations, but the mechanism of sperm activation seems to be closer to other fish species where osmolality prohibits sperm activation in seminal plasma. In these species, hypoosmolality is the primary signal for sperm Ca(2+)-dependent signaling of axonemal beating.

• MeSH
• bičík spermie účinky léků   metabolismus   fyziologie   MeSH
• blokátory kalciových kanálů farmakologie   MeSH
• chelátory farmakologie   MeSH
• draslík farmakologie   fyziologie   MeSH
• EGTA farmakologie   MeSH
• motilita spermií účinky léků   MeSH
• nifedipin farmakologie   MeSH
• osmolární koncentrace MeSH
• proteinkinasy závislé na vápníku a kalmodulinu antagonisté a inhibitory   MeSH
• rybí proteiny antagonisté a inhibitory   MeSH
• ryby MeSH
• sulfonamidy farmakologie   MeSH
• vápník farmakologie   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• blokátory kalciových kanálů MeSH
• chelátory MeSH
• draslík MeSH
• EGTA MeSH
• nifedipin MeSH
• proteinkinasy závislé na vápníku a kalmodulinu MeSH
• rybí proteiny MeSH
• sulfonamidy MeSH
• vápník MeSH
• W 7 MeSH Prohlížeč

OBJECTIVES: We studied a) mitogen lectin (PHA) evoked changes of Na+/K+-ATPase activity in functionally different lymphocytes or brain cortex cells and b) quantitative relationship between PHA- evoked early enzyme activation and late lymphocyte proliferation were analyzed. MATERIALS AND METHODS: We performed biochemical analyses of Pi released from ATP by Na+/K+-ATPase activity. Lymphocyte proliferation was assayed by 3H-thymidine incorporation. RESULTS: We demonstrated PHA stimulated Na+/K+-ATPase activity of mouse spleen lymphocytes or freshly isolated brain cortex cells. Besides this, we estimated high stimulation of Na+/K+-ATPase activity and subsequent late 3H-thymidine incorporation into pig lymphocytes as both PHA dose and K+ ion concentration dependent. CONCLUSIONS: Thus, early PHA dose-dependent stimulation of Na+/K+-ATPase activity is a more general response in different animal species and functionally different cells. We measured both cell type- and PHA-dose dependent enzyme activity stimulation. We can suggest that intensity of early PHA induced Na+/K+-ATPase activation could be in relationship to subsequent elevated level of T lymphocyte proliferation. The Na+/K+-ATPase can be a part of mitogen lectin evoked signal transduction mechanisms.

• MeSH
• aktivace lymfocytů účinky léků   MeSH
• buněčné kultury MeSH
• draslík farmakologie   MeSH
• fytohemaglutininy farmakologie   MeSH
• mitogeny farmakologie   MeSH
• mozková kůra účinky léků   metabolismus   MeSH
• myši inbrední CBA MeSH
• myši MeSH
• prasata MeSH
• slezina účinky léků   metabolismus   MeSH
• sodíko-draslíková ATPasa metabolismus   MeSH
• T-lymfocyty metabolismus   MeSH
• thymus účinky léků   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• fytohemaglutininy MeSH
• mitogeny MeSH
• phytohemagglutinin L protein, Phaseolus vulgaris MeSH Prohlížeč
• sodíko-draslíková ATPasa MeSH