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- Wan, Y., et al.
(författare)
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Design, synthesis, and biological evaluation of the first selective nonpeptide AT2 receptor agonist
- 2004
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Ingår i: J Med Chem. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 47:24, s. 5995-6008
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Tidskriftsartikel (refereegranskat)abstract
- The first druglike selective angiotensin II AT(2) receptor agonist (21) with a K(i) value of 0.4 nM for the AT(2) receptor and a K(i) > 10 microM for the AT(1) receptor is reported. Compound 21, with a bioavailability of 20-30% after oral administration and a half-life estimated to 4 h in rat, induces outgrowth of neurite cells, stimulates p42/p44(mapk), enhances in vivo duodenal alkaline secretion in Sprague-Dawley rats, and lowers the mean arterial blood pressure in anesthetized, spontaneously hypertensive rats. Thus, the peptidomimetic 21 exerts a similar biological response as the endogenous peptide angiotensin II after selective activation of the AT(2) receptor. Compound 21, derived from the prototype nonselective AT(1)/AT(2) receptor agonist L-162,313 will serve as a valuable research tool, enabling studies of the function of the AT(2) receptor in more detail.
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| 2. |
- Wan, Y., et al.
(författare)
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First reported nonpeptide AT1 receptor agonist (L-162,313) acts as an AT2 receptor agonist in vivo
- 2004
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Ingår i: J Med Chem. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 47:6, s. 1536-1546
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Tidskriftsartikel (refereegranskat)abstract
- In this investigation, it is demonstrated that the first nonpeptide AT(1) receptor agonist L-162,313 (1), disclosed in 1994, also acts as an agonist at the AT(2) receptor. In anesthetized rats, administration of compound 1 intravenously or locally in the duodenum increased duodenal mucosal alkaline secretion, effects that were sensitive to the selective AT(2) receptor antagonist PD-123,319. The data strongly suggest that 1 is an AT(2) receptor agonist in vivo. To the best of our knowledge, this substance is the first nonpeptidic low-molecular weight compound with an agonistic effect mediated through the AT(2) receptor.
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| 3. |
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| 4. |
- Snygg, Johan, 1963, et al.
(författare)
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Intestinal nitric oxide output during reduced mucosal blood flow in healthy volunteers.
- 2003
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Ingår i: Critical care medicine. - 0090-3493. ; 31:8, s. 2198-204
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Nitric oxide regulates epithelial permeability and other properties of the intestinal mucosal barrier. It previously has been shown in animals that intestinal mucosal nitric oxide production is impaired during gut hypoperfusion. The study was performed to confirm the presence of intestinal mucosal nitric oxide production in humans and to investigate the effect of gut hypoperfusion due to moderate arterial hypotension on intestinal nitric oxide concentrations. DESIGN: Open study where each subject served as his own control. SETTING: Clinical research laboratory. SUBJECTS: Nine healthy volunteers were intubated with a nasogastrointestinal tube for recordings in the distal duodenum. Intestinal nitric oxide output and motility were assessed by tonometry and manometry, respectively. Laser Doppler flowmetry and plasma angiotensin II concentration were used to investigate mucosal perfusion and a vasoregulatory response. INTERVENTIONS: Moderate hypotension was induced with lower body negative pressure over 1 hr. MEASUREMENTS AND MAIN RESULTS: Intestinal nitric oxide production varied in parallel with the migrating motor complex. Low values were obtained during phase I and peak values during phase III. Lower body negative pressure was initiated at a well-defined point in the migrating motor complex cycle. It was followed by a 40 +/- 6% reduction of laser Doppler flow signal, a 778 +/- 138% increase in angiotensin II, and a reduction in intestinal mucosal nitric oxide production by 48 +/- 8%. After lower body negative pressure, laser Doppler signal and angiotensin II concentrations returned to baseline levels within 1 hr, whereas intestinal nitric oxide output remained decreased. CONCLUSIONS: Intestinal tonometry in humans exhibits a considerable mucosal nitric oxide formation that varies in relation to intestinal motility. Intestinal nitric oxide production is depressed during conditions with lowered mucosal blood perfusion.
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| 5. |
- Von Bothmer, Charlotte, 1969, et al.
(författare)
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Stimulated murine macrophages as a bioassay for H. pylori-related inhibition of nitric oxide production.
- 2003
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Ingår i: Scandinavian journal of gastroenterology. - 0036-5521. ; 38:4, s. 380-6
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Interference with the L-arginine/nitric oxide pathway may be a virulence strategy for the gastric pathogen Helicobacter pylori. This study evaluates a bioassay for such inhibitory actions on nitric oxide synthase. METHODS: Cultured murine macrophages were stimulated by lipopolysaccharide and interferon-gamma. Nitric oxide synthesis and the expression of inducible nitric oxide synthase (iNOS) at increasing concentrations of L-arginine were analysed using chemiluminescence and Western blotting, respectively. RESULTS: The bioassay was evaluated against nitrite accumulation and two established NOS inhibitors. Bacterial extracts or whole cells of one H. pylori strain inhibited nitric oxide production at low L-arginine concentrations (2-20 microM). A higher concentration of L-arginine (200 microM) was not associated with such inhibition. The iNOS expression was not affected by any of the additives compared to stimulated controls. CONCLUSIONS: This bioassay is a reliable and simple method for analysing iNOS inhibition, resolving effects on enzyme activity or enzyme expression. H. pylori water extract and whole cells exert an L-arginine-dependent NOS inhibition, not influencing iNOS expression.
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