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MeSH: tetraethylamoniové sloučeniny

14 záznamů v Medvik Filtry

Článek online

15-oxo-ETE-induced internal carotid artery constriction in hypoxic rats is mediated by potassium channels

Wang, D
Autor Wang, D Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
Liu, Y
Autor Liu, Y Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
Lu, P
Autor Lu, P Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
Zhu, D
Autor Zhu, D Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
Zhu, Y
Autor Zhu, Y Department of Neurology, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China

Physiological research. 2016 ; 65 (3) : 391-399. [pub] 20151008

Physiol. Res. (Print)
ISSN 1802-9973
Medvik
Zdroj

Our own study as well as others have previously reported that hypoxia activates 15-lipoxygenase (15-LO) in the brain, causing a series of chain reactions, which exacerbates ischemic stroke. 15-hydroxyeicosatetraenoic acid (15-HETE) and 15-oxo-eicosatetraenoic acid (15-oxo-ETE/15-KETE) are 15-LO-specific metabolites of arachidonic acid (AA). 15-HETE was found to be rapidly converted into 15-oxo-ETE by 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in some circumstances. We have demonstrated that 15-HETE promotes cerebral vasoconstriction during hypoxia. However, the effect of 15-oxo-ETE upon the contraction of cerebral vasculature remains unclear. To investigate this effect and to clarify the underlying mechanism, we performed immunohistochemistry and Western blot to test the expression of 15-PGDH in rat cerebral tissue, examined internal carotid artery (ICA) tension in isolated rat ICA rings. Western blot and reverse transcription polymerase chain reaction (RT-PCR) were used to analyze the expression of voltage-gated potassium (Kv) channels (Kv2.1, Kv1.5, and Kv1.1) in cultured cerebral arterial smooth muscle cells (CASMCs). The results showed that the levels of 15-PGDH expression were drastically elevated in the cerebral of rats with hypoxia, and 15-oxo-ETE enhanced ICA contraction in a dose-dependent manner. This effect was more significant in the hypoxic rats than in the normoxic rats. We also found that 15-oxo-ETE significantly attenuated the expression of Kv2.1 and Kv1.5, but not Kv1.1. In conclusion, these results suggest that 15-oxo-ETE leads to the contraction of the ICA, especially under hypoxic conditions and that specific Kv channels may play an important role in 15-oxo-ETE-induced ICA constriction.

MeSH
4-aminopyridin MeSH
arteria carotis interna metabolismus MeSH
draslíkové kanály metabolismus MeSH
glibenklamid MeSH
hydroxyprostaglandindehydrogenasy metabolismus MeSH
hypoxie metabolismus MeSH
kyseliny arachidonové metabolismus MeSH
potkani Wistar MeSH
techniky in vitro MeSH
tetraethylamonium MeSH
vazokonstrikce * MeSH
zvířata MeSH
Check Tag
mužské pohlaví MeSH
zvířata MeSH
Publikační typ
časopisecké články MeSH

Článek

Focal cerebral ischemia induces the neurogenic potential of mouse Dach1-expressing cells in the dorsal part of the lateral ventricles

Neuroscience. 2013 ; 240 (-) : 39-53.

ISSN 1873-7544
Medvik
Zdroj

The mouse Dach1 gene, involved in the development of the neocortex and the hippocampus, is expressed by neural stem cells (NSCs) during early neurogenesis, and its expression also continues in a subpopulation of cells in the dorsal part of the lateral ventricles (LV) of the adult mouse brain. In this study we aimed to elucidate the role of Dach1-expressing cells in adult neurogenesis/gliogenesis under physiological as well as post-ischemic conditions, employing transgenic mice in which the expression of green fluorescent protein (GFP) is controlled by the D6 promotor of the mouse Dach1 gene. A neurosphere-forming assay of GFP⁺ cells isolated from the dorsal part of the LV was carried out with subsequent differentiation in vitro. To elucidate the neurogenic/gliogenic potential of GFP⁺ cells in the dorsal part of the LV, in situ immunohistochemical/electrophysiological analyses of GFP⁺ cells in adult sham-operated brains (controls) and those after middle cerebral artery occlusion (MCAo) were performed. The GFP⁺ cells isolated from the dorsal part of the LV of controls formed neurospheres and differentiated solely into a glial phenotype, while those isolated after MCAo also gave rise to cells with the properties of neuronal precursors. In situ analyses revealed that GFP⁺ cells express the phenotype of adult NSCs or neuroblasts in controls as well as following ischemia. Following MCAo we found a significantly increased number of GFP⁺ cells expressing doublecortin as well as a number of GFP⁺ cells migrating through the rostral migratory stream into the olfactory bulb, where they probably differentiated into calretinin⁺ interneurons. Collectively, our results suggest the involvement of the mouse Dach1 gene in adult neurogenesis; cells expressing this gene exhibit the properties of adult NSCs or neuroblasts and respond to MCAo by enhanced neurogenesis.

Článek online

Vasorelaxing action of vasonatrin peptide is associated with activation of large-conductance Ca2+-activated potassium channels in vascular smooth muscle cells

Physiological research. 2010 ; 59 (2) : 187-194.

Medvik
Zdroj

The aim of this study was to test the hypothesis that vasorelaxing action of vasonatrin peptide (VNP) is due to activation of the large-conductance Ca2+-activated potassium channel (BKCa) via guanylyl cyclase (GC)-coupled natriuretic peptide receptors (NPRs) in vascular smooth muscle cells (VSMCs). Contraction experiments were performed using human radial artery, whereas BKCa current by patch clamp was recorded in cells from rat mesenteric artery. Contractility of rings cut from human radial artery was detected in vitro. As a result, VNP induced a dose-dependent vasorelaxation of human radial artery, which could be mimicked by 8-Br-cGMP, and suppressed by TEA, a blocker of BKCa, HS-142-1, a blocker of GC-coupled NPRs, or methylene blue (MB), a selective inhibitor of guanylyl cyclase. Sequentially, whole-cell K+ currents were recorded using patch clamp techniques. BKCa current of VSMCs isolated from rat mesentery artery was obtained by subtracting the whole cell currents after applications of 10-7 mol/l iberiotoxin (IBX) from before its applications. In accordance with the results of arterial tension detection, BKCa current was significantly magnified by VNP, which could also be mimicked by 8-Br-cGMP, whereas suppressed by HS-142-1, or MB. Taken together, VNP acts as a potent vasodilator, and NPRA/B-cGMP-BKCa is one possible signaling system involved in VNP induced relaxation.

Článek

Influence of calcium-dependent potassium channel blockade and nitric oxide inhibition on norepinephrine-induced contractions in two forms of genetic hypertension

Journal of the American Society of Hypertension. 2010 ; 4 (3) : 128-34.

J Am Soc Hypertens
ISSN 1933-1711
Medvik
Zdroj

The activation of Ca(2+)-dependent K(+) channels (BK(Ca)) leads to the attenuation of vascular contraction. Our study aimed to evaluate BK(Ca) influence on norepinephrine (NE)-induced femoral artery contraction in two forms of genetic hypertension. NE dose-response curves were studied before and after BK(Ca) blockade or after combined blockade of BK(Ca) and NO synthase (NOS) in femoral arteries with intact endothelium from normotensive Wistar (WIS), hypertensive hereditary hypertriglyceridemic (HTG), or spontaneously hypertensive rats (SHR). NE-induced contractions of femoral arteries were augmented in both hypertensive strains compared with Wistar rats, but acetylcholine-induced relaxation was impaired in HTG only. The increase of basal vascular tone of isolated arteries after BK(Ca) blockade was similar in all rat strains, but subsequent NOS inhibition increased basal vascular tone more in vessels from both hypertensive rat strains. NOS inhibition increased sensitivity to NE in all strains, but BK(Ca) blockade in SHR only. Neither treatment enhanced maximal NE-induced contraction. NO-dependent attenuation of NE-induced contractions was greater in SHR than HTG or Wistar vessels, whereas large conductance Ca(2+)-dependent K(+) channels may play a greater role in modulating vascular contraction in the severe form of hypertension.

Článek online

Aktivita komerčne vyrábaných dezinfektantov voči Stenotrophomonas maltophilia in vitro [In vitro activity of commercially available disinfectants against Stenotrophomonas maltophilia]

Epidemiologie, mikrobiologie, imunologie. 2005 ; Roč. 54 (č. 2) : s. 78-83.

ISSN 1210-7913
Medvik
Zdroj

Študovala sa in vitro antibakteriálna účinnosť 14 komerčne vyrábaných dezinfektantov voči nozokomiálnemu patogénu Stenotrophomonas maltophilia. Testované prípravky predstavovali 5 „čistých“ kvartérnych amóniových zlúčenín (KAZ) a 9 kombinovaných prípravkov s ďalšími zložkami, ale so základnou zložkou KAZ. Antibakteriálna účinnosť bola vyjadrená hodnotami MIC a ED50 ako aj inhibíciou rýchlosti inkorporácie radioaktívnych prekurzorov [14C] adenínu a [14C] leucínu. Podľa aktivity dezinfektanty boli rozdelené do štyroch skupín. Prvá skupina obsahovala prípravky so silným inhibičným účinkom (MIC 0,045–0,09 μg/ml) kde patrili Benzalkonium chlorid a Triquart. Druhá skupina obsahovala prípravky s dobrou antibakteriálnou účinnosťou (MIC 0,19–0,78 μg/ml), tretiu skupinu tvorili prípravky s hodnotami MIC 1,56–25 μg/ml. Najnižšiu účinnosť prejavil Cetrimid (MIC 50–100 μg/ml) a patril do štvrtej skupiny. Účinok študovaných prípravkov na biosyntetické procesy vyjadrený hodnotami R (IC50 Ade : IC50 Leu) ukázal, že tieto hodnoty byli < 1 iba po pôsobení látok Hexaquart plus, Diesen forte, Sokrena, Forten, ID 212 a Cetrimid. Nižšie hodnoty IC50Ade, IC50študovaných prípravkov naznačujú zásah do syntézy nukleových kyselín a proteínov, čo sa prejavilo inhibíciou oboch prekurzorov. Endogénnu respiráciu najúčinnejšie inhibovali takmer na 50% pri koncentrácii 0,78 μg/ml Cetrimid a Microbac forte. Respiráciu totálne inhibovali prípravky Almyrol, Diesen forte, Microbac forte v koncentrácii 6,25 μg/ml a prípravky FD312, Triquart, Hexaquart plus, Hexaquart S, ID212, TPH 5225 v koncentrácii 12,5 μg/ml.

In vitro antibacterial efficacy of 14 commercially available disinfectants against the hospital pathogen Stenotrophomonas maltophilia was tested. The test disinfectants included 5 “pure” quartenary ammonium compounds (QACs) and 9 combination formulations with QACs as the major ingredient. Antibacterial efficacy was expressed as MIC, ED50and inhibition of the rate of incorporation of radioactive precursors [14C] adenine and [14C] leucine. Based on their activity, the disinfectants were divided into four groups. Group I characterized by high inhibitory activity (MIC 0.045–0.09 μg/ml) comprised benzalconium chloride and Triquart. Group II included formulations with good antibacterial activity (MIC 0.19–0.78 μg/ml) while group III formulations showed MICs between 1.56 and 25 μg/ml. The less active Cetrimid (MIC 50–100 μg/ml) was classified into group IV. When effects on biosynthetic processes expressed as R values (IC50Ade : IC50 Leu) were tested, R < 1 was only recorded for the following formulations: Hexaquart plus, Diesen forte, Sokrena, Forten, ID 212 and Cetrimid. Lower values of IC50 Ade and IC50 Leu are suggestive of effects on the synthesis of nucleic acids and proteins leading to inhibition of the two precursors. Endogenous respiration was almost 50 % inhibited by Cetrimid and Microbac forte at a concentration of 0.78 μg/ml, and 100 % inhibited by Almyrol, Diesen forte and Microbac forte at a concentration of 6.25 μg/ml and by FD312, Triquart, Hexaquart plus, Hexaquart S, ID 212, TPH 5225 at a concentration of 12.5 μg/ml.