NO Effects (no + effects)

Distribution by Scientific Domains

Selected Abstracts

Nitric oxide counteracts angiotensin II induced contraction in efferent arterioles in mice

A. Patzak
Abstract Aim:, Efferent arterioles (Ef) are one of the final control elements in glomerular haemodynamics. The influence of nitric oxide (NO) on Ef remains ambiguous. Methods:, To test the hypothesis that endothelial NO plays an important role in this context, afferent arterioles (Af) and Ef of wild-type mice (WT), and Ef of mice lacking the endothelial NO synthetase [eNOS(,/,)] were perfused. Perfusion was performed in Ef via Af (orthograde) as well as from the distal end of Ef (retrograde), which provides an estimate for the importance of substances derived from the glomerulus. Angiotensin II (Ang II) was added in doses ranging from 10,12 to 10,6 mol L,1 to the bath solution. Results:, Ang II reduced the luminal diameter of Af to 68 7 and in Ef to 55 8% during orthograde, and to 35 6% during retrograde perfusion (10,6 mol L,1 Ang II) in WT. Pre-treatment with NG -Nitro- l -arginine-methylester (l -NAME) (10,4 mol L,1) increased the Ang II sensitivity in retrograde (17 9%) and orthograde perfused Ef (19 9%). The Ang II sensitivity was enhanced in eNOS(,/,) mice compared with WT, too. Already at a dose of Ang II 10,9 mol L,1, luminal diameters diminished to 8 7 and 7 4%. Conclusion:, The increased Ang II sensitivity during l -NAME pre-treatment and in eNOS(,/,) mice indicates a strong counteraction of endothelial derived NO on Ang II induced contraction in Ef. Moreover, Ef are similarly sensitive to Ang II during either retrograde or orthograde perfusion in the absence of NO effects, suggesting that NO mediates, at least in part, the action of potential vasodilatory substances from the glomerulus. [source]

Role of the nitric oxide/cyclic GMP pathway and extracellular environment in the nitric oxide donor-induced increase in dopamine secretion from PC12 cells: a microdialysis in vitro study

Pier Andrea Serra
Abstract In vitro microdialysis was used to investigate the mechanism of nitric oxide (NO) donor-induced changes in dopamine (DA) secretion from PC12 cells. Infusion of the NO-donor S-nitroso- N -acetylpenicillamine (SNAP, 1.0 mm) induced a long-lasting increase in DA and 3-methoxytyramine (3-MT) dialysate concentrations. SNAP-induced increases were inhibited either by pre-infusion of the soluble guanylate cyclase (sGC) inhibitor 1H-[1,2,4] oxadiazolo[4,3]quinoxalin-1-one (ODQ, 0.1 mm) or by Ca2+ omission. Ca2+ re-introduction restored SNAP effects. SNAP-induced increases in DA + 3-MT were unaffected by co-infusion of the l -type Ca2+ channel inhibitor nifedipine. The NO-donor (+/,)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (NOR-3, 1.0 mm) induced a short-lasting decrease in dialysate DA + 3-MT. Ascorbic acid (0.2 mm) co-infusion allowed NOR-3 to increase dialysate DA + 3-MT. ODQ pre-infusion inhibited NOR-3 + ascorbic acid-induced DA + 3-MT increases. Infusion of high K+ (75 mm) induced a 2.5-fold increase in dialysate DA + 3-MT. The increase was abolished by NOR-3 co-infusion. Conversely, co-infusion of ascorbic acid (0.2 mm) with NOR-3 + high K+ restored high K+ effects. Co-infusion of nifedipine inhibited high K+ -induced DA + 3-MT increases. These results suggest that activation of the NO/sGC/cyclic GMP pathway may be the underlying mechanism of extracellular Ca2+ -dependent effects of exogenous NO on DA secretion from PC12 cells. Extracellular Ca2+ entry may occur through nifedipine-insensitive channels. NO effects and DA concentrations in dialysates largely depend on both the timing of NO generation and the extracellular environment in which NO is generated. [source]

Extended treatment of older cigarette smokers

ADDICTION, Issue 6 2009
Sharon M. Hall
ABSTRACT Aims Tobacco dependence treatments achieve abstinence rates of 25,30% at 1 year. Low rates may reflect failure to conceptualize tobacco dependence as a chronic disorder. The aims of the present study were to determine the efficacy of extended cognitive behavioral and pharmacological interventions in smokers , 50 years of age, and to determine if gender differences in efficacy existed. Design Open randomized clinical trial. Setting A free-standing, smoking treatment research clinic. Participants A total of 402 smokers of , 10 cigarettes per day, all 50 years of age or older. Intervention Participants completed a 12-week treatment that included group counseling, nicotine replacement therapy (NRT) and bupropion. Participants, independent of smoking status, were then assigned randomly to follow-up conditions: (i) standard treatment (ST; no further treatment); (ii) extended NRT (E-NRT; 40 weeks of nicotine gum availability); (iii) extended cognitive behavioral therapy (E-CBT; 11 cognitive behavioral sessions over a 40-week period); or (iv) E-CBT plus E-NRT (E-combined; 11 cognitive behavioral sessions plus 40 weeks nicotine gum availability). Measurements Primary outcome variable was 7-day point prevalence cigarette abstinence verified biochemically at weeks 24, 52, 64 and 104. Findings The most clinically important findings were significant main effects for treatment condition, time and the treatment time interaction. The E-CBT condition produced high cigarette abstinence rates that were maintained throughout the 2-year study period [(week 24 (58%), 52 (55%), 64 (55%) and 104 (55%)], and was significantly more effective than E-NRT and ST across that period. No other treatment condition was significantly different to ST. No effects for gender were found. Conclusions Extended cognitive behavioral treatments can produce high and stable cigarette abstinence rates for both men and women. NRT does not add to the efficacy of extended CBT, and may hamper its efficacy. Research is needed to determine if these results can be replicated in a sample with a greater range of ages, and improved upon with the addition of medications other than NRT. [source]

Effects of somatic cell counts on the physicochemical and rheological properties of yoghurt made from sheep's milk

Masoud Najaf Najafi
Summary In the present work, yoghurts were made from sheep's milk with two different somatic cell count (SCC), at low (200 000 cells mL,1) and high (750 000 cells mL,1) levels. The characteristics of the final product were analysed for pH, acidity, protein, total solids, fat, syneresis, water holding capacity (WHC) and apparent viscosity. Samples were analysed on days 1, 7 and 14 after production of yoghurts. The SCC had no significant effect either on the acidity or pH of the yoghurt at 24 h (P > 0.05) but a significant effect (P < 0.05) was observed at 168 h. No effects of SCC were observed on total solids and fat content of the yoghurt after 24 and 168 h. High SCC (HSCC) yoghurt had higher protein content (P < 0.05). The yoghurt with the highest SCC had the highest level of syneresis. Viscosity of HSCC yoghurt was higher than that of the low SCC yoghurt on days 1, 7 and 14 of storage. The flow properties also showed that the low SCC yoghurt was softer than that from milk with high content in somatic cells. [source]