Search results for "Potassium Chloride"

Effects of ouabain on human bronchial muscle in vitro

2003

The effects of ouabain, an inhibitor of the plasmalemmal Na(+)/K(+)-ATPase activity, were examined in human isolated bronchus. Ouabain produced concentration-dependent contraction with -logEC(50)=7.16+/-0.11 and maximal effect of 67+/-4% of the response to acetylcholine (1 mM). Ouabain (10 microM)-induced contraction was epithelium-independent and was not depressed by inhibitors of cyclooxygenase and lipoxygenase, antagonists of muscarinic, histamine H(1)-receptors and alpha-adrenoceptors, or neuronal Na(+) channel blockade. The inhibition of ouabain contraction in tissues bathed in K(+)-free medium, and the inhibition by ouabain of the K(+)-induced relaxation confirm that the contractile a…

The ionic dependence of calcium efflux from guinea pig auricles.

1968

K+ and Na+ effects on the gelation properties of κ-Carrageenan

2004

The effects of K(+), Na(+) ions and their mixture on the conformational transition and macroscopic gel properties of kappa-Carrageenan system have been studied using different experimental techniques. The macroscopic gelation properties of kappa-Carrageenan were found to be dependent upon cosolute type. Indeed, a more ordered and strong gel was obtained in the presence of K(+) with respect to Na(+) ions. The gel properties obtained using mixtures of two cosolutes are shown to depend on the [K(+)]/[Na(+)] ratio.

Modulation of neuronal phospholipase D activity under depolarizing conditions

1999

Neuronal phospholipase D (PLD) activity was hypothesized to be involved in vesicle trafficking and endocytosis and, possibly, transmitter release. We here report that prolonged depolarization of rat hippocampal slices by potassium chloride (KCl) or 4-aminopyridine inhibited PLD activity. Similarly, PLD activity in rat cortical synaptosomes was significantly inhibited by depolarizing agents including veratridine and ouabain. Inhibition of calcium/calmodulin kinase II (CaMKII) which positively modulates synaptosomal PLD activity [Sarri et al. (1998) FEBS Lett. 440, 287-290] by KN-62 caused a further reduction of PLD activity in depolarized synaptosomes. Depolarization-induced inhibition of PL…

Response of the Saccharomyces cerevisiae Mpk1 Mitogen-Activated Protein Kinase Pathway to Increases in Internal Turgor Pressure Caused by Loss of Ppz…

2004

ABSTRACT The Mpk1 pathway of Saccharomyces cerevisiae is a key determinant of cell wall integrity. A genetic link between the Mpk1 kinase and the Ppz phosphatases has been reported, but the nature of this connection was unclear. Recently, the Ppz phosphatases were shown to be regulators of K + and pH homeostasis. Here, we demonstrate that Ppz-deficient strains display increased steady-state K + levels and sensitivity to increased KCl concentrations. Given these observations and the fact that K + is the major determinant of intracellular turgor pressure, we reasoned that the connection between PPZ1 and - 2 and MPK1 was due to the combination of increased internal turgor pressure in Ppz-defic…

K-region oxides and imines derived from alkylated benz[α]anthracene congeners: synthesis, stability in aqueous media and mutagenicity

1994

The K-region oxides and imines of benz[a]anthracene, 1-methylbenz[a]anthracene, 7-methylbenz[a]anthracene, 7-ethylbenz[a]anthracene and 7,12-dimethylbenz[a]anthracene were synthesized and characterized (melting point, 1H-NMR and electron impact mass spectra, elemental analysis, IR spectroscopy). All 10 compounds showed high mutagenic activity in Salmonella typhimurium (reversion of his- strains TA97, TA98, TA100 and TA104). The arene imines were more potent than the corresponding arene oxides. Alkyl substitutions strongly influenced the activities. Furthermore, all compounds were more active when exposure took place in the absence of inorganic ions than when KCl (125 mM) was present. The in…

Strong influence of the exposure medium on mutagenicity in the Ames test: 7-methylbenz[a]anthracene-5,6-oxide.

1991

We have previously shown that the activity of the ionized mutagen, 1-hydroxmethylpyrene sulphate, is strongly enhanced in Salmonella typhimurium TA98, when KCl is present in the exposure medium (50-fold at a concentration of 125 mM KCl) and that the halogen ion is responsible for this effect. Here we show that KCl has the opposite effect on the activity of the lipophilic mutagen, 7-methylbenz[a]anthracene-5,6-oxide, (10-fold decrease at a concentration of 125 mM) and that K+ accounts for this influence. Many other solutes also decreased the mutagenicity of 7-methylbenz[a]anthracene-5,6-oxide, but to a smaller extent than the K+ salts. The stability of 7-methylbenz[a]anthracene-5,6-oxide did…

CCDC 1425264: Experimental Crystal Structure Determination

2016

Related Article: T. Mäkelä, K. Rissanen|2016|Dalton Trans.|45|6481|doi:10.1039/C6DT00414H

Sulfotransferase-mediated mutagenicity of 1-hydroxymethylpyrene and 4H-cyclopenta[def]chrysen-4-ol and its enhancement by chloride anions.

1993

1-Hydroxymethylpyrene (HMP), a primary benzylic alcohol, and 4H-cyclopenta[def]chrysen-4-ol (OH-CPC), a secondary benzylic alcohol, were investigated for mutagenicity in Salmonella typhimurium (reversion of the his- strain TA98) in the presence of various xenobiotic-metabolizing systems. In the direct test, HMP was inactive and OH-CPC was very weakly active. In the presence of NADPH-fortified postmitochondrial fraction from rat liver (S9/NADPH), no activation of OH-CPC was observed, whereas strong mutagenic effects were elicited by HMP. In the presence of cytosol and 3'-phosphoadenosine-5'-phosphosulfate (PAPS), both alcohols were activated to potent mutagens. For equal mutagenic effects, a…

Isolated in-vitro perfusion of pig hearts obtained from the abattoir: an alternative to animal experiments?

1994

Isolated pig hearts (German farm pigs) were characterized after global in-vivo ischaemia as a potential alternative to in-vivo animal studies. Hearts were harvested from adult farm swine at the abattoir 10.3 +/- 2.1 min after incision of the carotid artery. They were immediately perfused and thereafter stored in ice-cold cardioplegic (St Thomas's) solution. After 38 +/- 3 min, retrograde perfusion was started with oxygenated pig blood (37 degrees C; 5000 U Heparin.l-1; pH 7.38 +/- 0.1; 11 mmol glucose.l-1) at a flow rate of 85 ml.min-1 100 g-1 wet weight (gww-1) for 30 min (n = 10). Additionally, shortly after obtaining the hearts, ATP and CP content were measured by enzymatic tests in 10 p…