Bathing Solution (bathing + solution)

Distribution by Scientific Domains

Selected Abstracts

In vitro studies on the effects of Saccharomyces boulardii and Bacillus cereus var. toyoi on nutrient transport in pig jejunum

G. Breves
The probiotics Saccharomyces boulardii and Bacillus cereus var. toyoi are nonpathogenic microbes which have been shown to affect certain functions of the mucosal barrier in pig jejunum such as electrogenic ion transport capacity and paracellular permeability. The present studies were performed to investigate potential effects of the probiotics on jejunal nutrient transport such as sodium-dependent glucose transport or proton-dependent dipeptide transport. For this purpose the in vitro Ussing-chamber technique was applied in order to examine net electrogenic ion flux rates (short circuit currents, Isc) across isolated intact jejunal epithelia in the absence and presence of either 10 mmol/l glucose (mucosal side) or two-fold application of 5 mmol/l glycyl- l -sarcosine or glycyl- l -glutamine to the mucosal bathing solution. Brush border membrane vesicles (BBMV) were prepared in order to characterize kinetic parameters (Vmax, Km) of Na-dependent glucose transport. Intestinal tissues were obtained from growing pigs in a weight range between 23 and 33 kg. All animals were fed twice daily and received 0.8,0.9 kg/day of a standard diet. After a 9- to 10-day adaptation period the diets for treated animals were either supplemented for 8 days with 1.7107 colony-forming units (CFU)/g feed of S. boulardii or for 3 weeks with 106 CFU/g feed B. cereus var. toyoi. Under basal conditions Isc values were not affected by different treatment protocols (controls: 0.74 0.04 eq/cm2 per h, n=9; S. boulardii: 0.74 0.12 eq/cm2 per h, n=7; B. cereus 0.68 0.09 eq/cm2 per h, n=5). Irrespective of dietary treatment, the addition of glucose resulted in significant increases of Isc indicating substantial onset of electrogenic net Na/glucose cotransport. Maximal Isc values occurred within 30 min and reached 2.79 0.41 eq/cm2 per h in control epithelia. This was significantly lower than found in S. boulardii (4.47 0.43 eq/cm2 per h, p < 0.05) and B. cereus var. toyoi tissues (4.45 0.31 eq/cm2 per h, p < 0.05). Gt values were 22.4 1.3 mS/cm2 in control animals and were significantly lower as shown in S. boulardii (p < 0.01) and B. cereus var. toyoi (p < 0.01)-treated animals (28.4 1.3 and 29.9 0.8 mS/cm2, respectively). Vmax values of Na-dependent glucose uptake into BBMV differed significantly between controls (0.64 0.08 nmol/mg protein per 10 s; n=5), S. boulardii (0.89 0.06 nmol/mg protein per 10 s; n=5, p < 0.05) and B. cereus var. toyoi preparations (1.08 0.05 nmol/mg protein per 10 s; n=3, p < 0.01). Km values were not significantly affected (control: 0.31 0.04 mmol/l, S. boulardii: 0.29 0.05 mmol/l, B. cereus var. toyoi: 0.21 0.01 mmol/l). Irrespective of dietary treatment, application of the dipeptide model substances glycyl- l -sarcosine or glycyl- l -glutamine resulted in significant increases of Isc indicating marked stimulation of electrogenic net H+/dipeptide cotransport. Highest Isc responses occurred in B. cereus var. toyoi preparations and lowest were found in control tissues. However, these differences were not significant. Gt values were not affected by different dietary treatments. The results clearly demonstrate that oral administration of either S. boulardii or B. cereus var. toyoi stimulates Na-dependent glucose absorption in pig jejunum. [source]

Influence of progesterone on myometrial contractility in pregnant mice treated with lipopolysaccharide

Hiroshi Anbe
Abstract Aim:, To evaluate the effect of progesterone on interleukin (IL)-6, prostaglandin (PG) E2 and nitric oxide (NO) metabolite (NOx) production and contractile activity by NO in pregnant mice treated with lipopolysaccharide (LPS). Methods:, Pregnant C57BL mice on day 14 of gestation were killed 6 h after i.p. injection of LPS (400 ,g/kg) or vehicle. Progesterone (2 mg) was subcutaneously injected 2 h before LPS treatment. Uterine rings were equilibrated in Krebs-Henseleit solution (37C) bubbled with 20% O2 and 5% CO2 (pH 7.4) for sampling and isometric tension recording. IL-6, PGE2 and NOx productions were measured from the bathing solution. Changes in spontaneous contractile activity in response to cumulative concentrations of l -arginine, diethylamine/nitric oxide (DEA/NO, the NO donor), and 8-bromo-cGMP (8-br-cGMP) were compared. Integral contractile activity over 10 min after each concentration was calculated and expressed as percentage change from basal activity. Statistical analyses were performed using one-way anova followed by Dunnett's test (significance was defined as P < 0.05). Results:, Interleukin-6 (34.7 6.0 pg/g tissue), PGE2 (66.8 6.7 pg/g tissue) and NOx (51.0 5.4 pmol/2 mL/g wet tissue) production were significantly stimulated by LPS treatment (138.2 23.2, 147.0 29.0, 98.6 16.2, respectively; P < 0.05). l -arginine, DEA/NO and 8-br-cGMP concentration-dependently inhibited spontaneous contractions in uterine rings both in LPS-treated and -untreated animals. Treatment with LPS significantly attenuated the maximal inhibition induced by l -arginine, DEA/NO and 8-br-cGMP in uterine rings from pregnant mice. Progesterone significantly decreased the levels of IL-6 production (74.9 12.1, P < 0.05), but not PGE2 and NOx production, and contractile responses by l -arginine, DEA/NO and 8-br-cGMP. Conclusions:, The administration of LPS is associated with increases in IL-6, PGE2 and NO, and these increases may or may not have a role to play in LPS-induced preterm labor. Progesterone reduced the LPS-induced increase in IL-6 production and this may be one of the ways that progesterone reduces the risk of preterm labor. [source]

Amitriptyline has a dual effect on the conductive properties of the epithelial Na channel

Florentina Pena
This study was undertaken with the aim of testing the action of amitriptyline on the epithelial Na channel (ENaC), which belongs to the same family (Deg/ENaC) as ASICs (acid-sensing ion channels) and many other putative members in the brain. We assumed that, having a common protein structure, characterization of the amitriptyline-ENaC interaction could help to elucidate the analgesic mechanism of this tricyclic antidepressant. Na-channel characteristics were derived from the analysis of blocker-induced lorentzian noise produced by amiloride. The effect of amitriptyline, present in the mucosal bathing solution, on the transepithelial short-circuit current (1sc) and conductance (Gt), and on the blocker-induced noise of apical Na channels, was studied on isolated ventral skin of the frog Rana ridibunda. Amitriptyline exerted a dual effect on the macroscopic short-circuit current and conductance of the epithelia, increasing these two parameters in the concentration range 0.1,50 ,M, while at higher concentrations (100,1000 ,M) it showed an inhibitory action. The decrease in the association rate (k01) of amiloride to the apical Na channels from 15.6 4.2 ,M,1 S,1 in control Cl-Ringer to 7.4 1.7 ,M,1 S,1 at 200 ,M amitriptyline in a concentration-dependent manner suggests a competitive binding of amitriptyline to the pyrazine ring binding site for amiloride. [source]

Ascorbate Enhances Photogeneration of Hydrogen Peroxide Mediated by the Iris Melanin,

Albert R. Wielgus
The iris in the human eye is exposed to UV and visible light transmitted by the cornea. This pigmented tissue is bathed with the aqueous humor (AqH), which contains high concentration of ascorbate. It has been postulated that the presence of ascorbate in AqH can contribute to increased photoproduction of H2O2 mediated by the iris melanin. In this study, we monitored generation of H2O2 induced by UV,VIS irradiation of bovine irides, bovine and human iris homogenates and iris melanin. Our data show that exogenous ascorbate significantly amplified the rate of H2O2 photoformation in all melanotic samples. Deactivation of endogenous catalase with NaN3 in bovine irides increased the level of the accumulated H2O2 in the bathing solution following sample irradiation. Photoformation of H2O2 in samples with exogenous ascorbate was accompanied by its photo-oxidation. Both photoprocesses exhibited significant wavelength dependence. EPR spectroscopy measurements showed that ascorbyl radical is an intermediate product of the ascorbate photo-oxidation. The photoproduction of H2O2 and photo-oxidation of ascorbate appear to be stoichiometric processes. No significant differences in the photoreactivity of iridial melanin from donors of different age and iris color was found. We postulate that also in vivo ascorbate increases the rate of iris melanin-mediated photoformation of H2O2 and its steady state concentration in AqH. [source]


Catalina Romero-Mndez
SUMMARY 1In the present study, we investigated the series of events involved in the contraction of tracheal smooth muscle induced by the re-addition of Ca2+ in an in vitro experimental model in which Ca2+ stores had been depleted and their refilling had been blocked by thapsigargin. 2Mean (SEM) contraction was diminished by: (i) inhibitors of store-operated calcium channels (SOCC), namely 100 mol/L SKF-96365 and 100 mol/L 1-(2-trifluoromethylphenyl) imidazole (to 66.3 4.4 and 41.3 5.2% of control, respectively); (ii) inhibitors of voltage-gated Ca2+ channels CaV1.2 channels, namely 1 mol/L nifedipine and 10 mol/L verapamil (to 86.2 3.4 and 76.9 5.9% of control, respectively); and (iii) 20 mol/L niflumic acid, a non-selective inhibitor of Ca2+ -dependent Cl, channels (to 41.1 9.8% of control). In contrast, contraction was increased 2.3-fold by 100 nmol/L iberiotoxin, a blocker of the large-conductance Ca2+ -activated K+ (BK) channels. 3Furthermore, contraction was significantly inhibited when Na+ in the bathing solution was replaced by N -methyl,d -glucamine (NMDG+) to 39.9 7.2% of control, but not when it was replaced by Li+ (114.5 24.4% of control). In addition, when Na+ had been replaced by NMDG+, contractions were further inhibited by both nifedipine and niflumic acid (to 3.0 1.8 and 24.4 8.1% of control, respectively). Nifedipine also reduced contractions when Na+ had been replaced by Li+ (to 10.7 3.4% to control), the niflumic acid had no effect (116.0 4.5% of control). 4In conclusion, the data of the present study demonstrate the roles of SOCC, BK channels and CaV1.2 channels in the contractions induced by the re-addition of Ca2+ to the solution bathing guinea-pig tracheal rings under conditions of Ca2+ -depleted sacroplasmic reticulum and inhibition of sarcoplasmic/endoplasmic reticulum calcium ATPase. The contractions were highly dependent on extracellular Na+, suggesting a role for SOCC in mediating the Na+ influx. [source]

Calmodulin binding to M-type K+ channels assayed by TIRF/FRET in living cells

Manjot Bal
Calmodulin (CaM) binds to KCNQ2,4 channels within their carboxy termini, where it regulates channel function. The existing data have not resolved the Ca2+ dependence of the interaction between the channels and CaM. We performed glutathione S-transferase (GST)-pull-down assays between purified KCNQ2,4 carboxy termini and CaM proteins to determine the Ca2+ dependence of the interaction in vitro. The assays showed substantial Ca2+ dependence of the interaction of the channels with wild-type (WT) CaM, but not with dominant-negative (DN) CaM. To demonstrate CaM,channel interactions in individual living cells, we performed fluorescence resonance energy transfer (FRET) between ECFP-tagged KCNQ2,4 channels and EYFP-tagged CaM expressed in CHO cells, performed under total internal reflection fluorescence (TIRF) microscopy, in which excitation light only penetrates several hundred nanometres into the cell, thus isolating membrane events. FRET was assayed between the channels and either WT or DN CaM, performed under conditions of normal [Ca2+]i, low [Ca2+]i or high [Ca2+]i induced by empirically optimized bathing solutions. The FRET data suggest a strong Ca2+ dependence for the interaction between WT CaM and KCNQ2, but less so for KCNQ3 and KCNQ4. FRET between all KCNQ2,4 channels and DN CaM was robust, and not significantly Ca2+ dependent. These data show interactions between CaM and KCNQ channels in living cells, and suggest that the interactions between KCNQ2,4 channels and CaM are likely to have Ca2+ -dependent and Ca2+ -independent components. [source]