Kinin B1 Receptor Enhances the Oxidative Stress in a Rat Model of Insulin Resistance: Outcome in Hypertension, Allodynia and Metabolic Complications

BACKGROUND: Kinin B(1) receptor (B(1)R) is induced by the oxidative stress in models of diabetes mellitus. This study aims at determining whether B(1)R activation could perpetuate the oxidative stress which leads to diabetic complications. METHODS AND FINDINGS: Young Sprague-Dawley rats were fed with 10% D-Glucose or tap water (controls) for 8-12 weeks. A selective B(1)R antagonist (SSR240612) was administered acutely (3-30 mg/kg) or daily for a period of 7 days (10 mg/kg) and the impact was measured on systolic blood pressure, allodynia, protein and/or mRNA B(1)R expression, aortic superoxide anion (O(2)(*-)) production and expression of superoxide dismutase (MnSOD) and catalase. SSR240612 reduced dose-dependently (3-30 mg/kg) high blood pressure in 12-week glucose-fed rats, but had no effect in controls. Eight-week glucose-fed rats exhibited insulin resistance (HOMA index), hypertension, tactile and cold allodynia and significant increases of plasma levels of glucose and insulin. This was associated with higher aortic levels of O(2)(*-), NADPH oxidase activity, MnSOD and catalase expression. All these abnormalities including B(1)R overexpression (spinal cord, aorta, liver and gastrocnemius muscle) were normalized by the prolonged treatment with SSR240612. The production of O(2)(*-) in the aorta of glucose-fed rats was also measured in the presence and absence of inhibitors (10-100 microM) of NADPH oxidase (apocynin), xanthine oxidase (allopurinol) or nitric oxide synthase (L-NAME) with and without Sar[D-Phe(8)]des-Arg(9)-BK (20 microM; B(1)R agonist). Data show that the greater aortic O(2)(*-) production induced by the B(1)R agonist was blocked only by apocynin. CONCLUSIONS: Activation of kinin B(1)R increased O(2)(*-) through the activation of NADPH oxidase in the vasculature. Prolonged blockade of B(1)R restored cardiovascular, sensory and metabolic abnormalities by reducing oxidative stress and B(1)R gene expression in this model

High-resolution CP-MAS 13C-NMR spectra of solid amylodextrins and amylose polymorphs.

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α-D-glucan-based dendritic nanoparticles prepared by <i>in vitro</i> enzymatic chain extension of glycogen

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Structure and distribution of glucomannan and sulfated glucan in the cell walls of the red alga Kappaphycus alvarezii (Gigartinales, Rhodophyta)

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Amylose chain behavior in an interacting context I. Influence of a nonchair ring on the maltose conformations

In the presence of steric constraints, flexible forms, i.e., skew (S), boat (B) or half-boat (H), were evoked from experimental data and conformational analyses by molecular mechanics calculations for glucopyranose rings of amylose fragments. This important case occurring, for example, in amylose-amylase complexes, requires careful analysis of these flexible ring forms prior to any further conformational study. The influence of a nonchair (flexible) form on the maltose conformation is systematically evaluated, with an appropriate strategy using 'Semirelaxed'' maps and comparing them with those obtained from already known chair-chair (C-4(1)-C-4(1)) maps. Therefore, new low-energy maltose conformations are described and classified from flexible-chair and chair-flexible maps. These conformations are well dispersed inside significantly larger contours in the (phi, psi) projection. In a second stage, the consequence of these flexible ring forms is discussed in terms of amylose propagation apart from these new maltose conformations. Two propagation parameters are defined (tau, Omega), related to the local curvature of the chain and the relative orientation of the two mean ring planes. Low-energy conformations of C-4(1)-C-4(1) maltose have almost the same curvature between the two rings, whereas their relative orientations have well-identified Omega values. On the contrary, the presence of one flexible conformations considerably increases the variation range of both propagation parameters. Thus, new low-energy conformations allow local curvatures yielding from almost perpendicular to linear pairs of glucopyranose rings with relative orientation coveting about three-fourths of the total domain. This description is essential to understand amylose conformations in catalytic site and subsites of the amylases.

α-amylose single crystals: unit cell refinement from synchrotron radiation microdiffraction data

Article de type "Notes"International audienc

Human nutrition and metabolism. Digestion of carbohydrate from white beans (Phaseolus vulgaris L.) in healthy humans

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