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Dietary salt supplementation selectively downregulates NPR-C receptor expression in kidney independently of ANP. Am J Physiol Renal Physiol 282: F220-F227, 2002. First published August 30, 2001; 10.1152/ajprenal.00166.2001.--Atrial natriuretic peptide (ANP) has negative modulatory effects on a variety of pathophysiological mechanisms; i.e., it inhibits hypoxia-induced pulmonary vasoconstriction and vascular remodeling and facilitates natriuresis and vasorelaxation in NaCl-supplemented subjects. We have previously demonstrated organ-selective potentiation of ANP in the pulmonary circulation of hypoxia-adapted animals by local downregulation of its clearance receptor (NPR-C; Li H, Oparil S, Meng QC, Elton T, and Chen Y-F. Am J Physiol Lung Cell Mol Physiol 268: L328-L335, 1995). The present study tested the hypothesis that NPR-C expression is attenuated selectively in kidneys of NaCl-supplemented subjects. Adult male wild-type (ANP+/+) and homozygous mutant (ANP-/-) mice were studied after 5 wk of normal or high-salt diets. Mean arterial pressure (MAP) and left (LV) and right ventricular (RV) mass were greater in ANP-/- mice than in ANP+/+ mice fed the normal-salt diet; salt supplementation induced increases in plasma ANP in ANP+/+ mice and in MAP and LV, RV, and renal mass in ANP-/- mice but not in ANP+/+ mice. NPR-C mRNA levels were selectively and significantly reduced (>60%) in kidney, but not in lung, brain, LV, or RV, by dietary salt supplementation in both genotypes. NPR-A mRNA levels did not differ among diet-genotype groups in any organ studied, cGMP content was significantly increased in kidney, but not in lung or brain, by dietary salt supplementation in both genotypes. These findings suggest that selective downregulation of NPR-C in the kidney in response to dietary salt supplementation may contribute to local elevation in ANP levels and may be functionally significant in attenuating the development of salt-sensitive hypertension. salt-sensitive hypertension; atrial natriuretic peptide; clearance receptor; atrial natriuretic peptide knockout mice; kidney

Evidences demonstrated the inhibition of hypoxic pulmonary hypertension in rats by the administration of herbal medicinal agent Allium sativum (garlic). The vasodilatory action of garlic, the vasoconstriction in isolated pulmonary arterial rings and the alveolar response to hypoxia were examined. A dose-dependent vasorelaxation in the intact and damaged endothelial lining in pulmonary arterial rings was observed. However, the administration of a nitric oxide synthase inhibitor restricted the vasodilatory action of garlic.

A study was conducted to test the hypothesis that blockade of the endothelin-A (ETA) receptor can prevent chronic hypoxia-induced pulmonary hypertension in the rat by reversing the increase in pulmonary artery pressure. Tests were performed through radioligand binding assay of the ligand, BQ-123, which is selective for the ETA receptor. The results of the study are presented and discussed.

Pulmonary hypertension occurs due to the effect of plasma endothelin-1 (ET-1), induced by hypoxia, on endothelin-A (ETA) receptors. An intravenous infusion of BQ-123, an ETA receptor antagonist, causes an increase in hypertension through an increase in the hypoxic response and the mean pulmonary artery pressure. The ET-1 levels, heart rate and arterial pressure remain unaffected by BQ-123.

Hypoxia reduces atrial natriuretic peptide clearance receptor gene expression in ANP knockout mice. Am J Physiol Lung Cell Mol Physiol 279: L511-L519, 2000.-- We tested the hypotheses that hypoxic exposure is associated with exacerbated pulmonary hypertension and right ventricular (RV) enlargement, reduced atrial natriuretic peptide (ANP) clearance receptor (NPR-C) expression, and enhanced B-type natriuretic peptide (BNP) expression in the absence of ANP. Male wild-type [ANP(+/+)], heterozygous [ANP(+/-)], and homozygous [ANP(-/-)] mice were studied after a 5-wk hypoxic exposure (10% [O.sub.2]). Hypoxia increased RV ANP mRNA and plasma ANP levels only in ANP(+/+) and ANP(+/-) mice. Hypoxia-induced increases in RV pressure were significantly greater in ANP(-/-) than in ANP(+/+) or ANP(+/-) mice (104 [+ or -] 17 vs. 45 [+ or -] 10 and 63 [+ or -] 7%, respectively) as were increases in RV mass (38 [+ or -] 4 vs. 26 [+ or -] 5 and 29 [+ or -] 4%, respectively). NPR-C mRNA levels were greatly reduced in the kidney, lung, and brain by hypoxia in all three genotypes. RV BNP mRNA and lung and kidney cGMP levels were increased in hypoxic mice. These findings indicate that disrupted ANP expression worsens hypoxic pulmonary hypertension and RV enlargement but does not alter hypoxia-induced decreases in NPR-C and suggest that compensatory increases in BNP expression occur in the absence of ANP. pulmonary hypertension

Zhang, Ming, Bao Luo, Shi-Juan Chen, Gary A. Abrams, and Michael B. Fallon. Endothelin-1 stimulation of endothelial nitric oxide synthase in the pathogenesis of hepatopulmonary syndrome. Am. J. Physiol. 277 (Gastrointest. Liver Physiol. 40): G944-G952, 1999.--Biliary cirrhosis in the rat triggers intrapulmonary vasodilatation and gas exchange abnormalities that characterize the hepatopulmonary syndrome. This vasodilatation correlates with increased levels of pulmonary microcirculatory endothelial nitric oxide synthase (eNOS) and hepatic and plasma endothelin-1 (ET-1). Prehepatic portal hypertension induced by portal vein ligation (PVL) does not cause similar changes, suggesting that ET-1 in cirrhosis may modulate pulmonary eNOS and vascular tone. We assessed whether ET-1 altered eNOS expression and nitric oxide production in bovine pulmonary artery endothelial cells (BPAECs) and if a 2-wk low-level intravenous ET-1 infusion in PVL animals modulated pulmonary eNOS levels, microcirculatory tone, and gas exchange. ET-1 caused a 2.5-fold increase in eNOS protein in BPAECs, inhibitable with an endothelin B receptor antagonist, and an increase in eNOS mRNA and nitrite production. ET-1 infusion in PVL animals caused increased pulmonary eNOS levels, intrapulmonary vasodilatation, and gas exchange abnormalities without increasing pulmonary arterial pressure. ET-1 produced during hepatic injury may contribute to the hepatopulmonary syndrome by modulating eNOS and inducing pulmonary microcicrulatory vasodilatation. endothelium; vasorelaxation; pulmonary; cirrhosis; expression

Interleukin-17A (IL-17A) is a pro-inflammatory cytokine secreted by a subset of memory T cells and other innate immune cells. It is associated with rheumatoid arthritis (RA) due to IL-17A expression in RA synovial fluid. The severe bone erosive rat adjuvant-induced arthritis (rAIA) and mouse collagen-induced arthritis (mCIA) models were used to address the therapeutic efficacy of anti-IL-17A treatment with a focused investigation on bone protection. In the rAIA model, treatment with anti-IL-17A completely alleviated arthritis, lowered the level of receptor activator of NFκκB ligand (RANKL), and inhibited structural damage to the bones. In the mCIA model, IL-17A neutralization coincident with arthritis development or in mice with established arthritis diminished joint swelling by inhibiting disease initiation and progression. Intriguingly, even the few joints that became outwardly severely inflamed in the presence of an anti-IL-17A antagonist had diminished joint histopathology scores compared to severely inflamed, control-treated mice. The bone-preserving property correlated with decreased RANKL message in severely inflamed paws of arthritic mice. These data identify IL-17A as a key factor in inflammation-mediated bone destruction and support anti-IL-17A therapy for the treatment of inflammatory bone diseases such as RA. [ABSTRACT FROM AUTHOR]

Objective: This study tested, in ovariectomized rats, whether (1) adventitial activation plays a role in the vascular injury response, and (2) inhibition of adventitial activation and the subsequent wave of cell proliferation moving from adventitia to neointima contributes to the estrogen-induced attenuation of neointima formation in balloon injured carotid arteries. Methods: Ovariectomized Sprague-Dawley rats were treated with either 17β-estradiol or vehicle beginning 72 h prior to balloon injury of the right common carotid artery and were sacrificed at 0, 3, 7, 14 and 28 days after injury. BrdU was administered 18 h and 12 h prior to sacrifice in order to quantitate mitotic activity in adventitia, media and neointima of the damaged vessel at specified times post injury. Results: Adventitial activation, evidenced by positive BrdU staining, was evident on the day of injury, peaked on day 3 and was resolved by day 7, thus preceding neointima formation. Numbers of BrdU labeled cells in adventitia on day 3 were significantly reduced in estrogen treated rats compared to controls. BrdU labeled cells were undetectable in media on the day of injury, appeared at day 3 and disappeared by day 14. Neointima appeared at day 7 and increased in area throughout the period of observation. Neointimal area and numbers of BrdU labeled cells in neointima were significantly reduced in estrogen treated rats compared to controls. These findings suggest that there is a wave of cell proliferation moving in an adventitia-to-lumen direction following endoluminal injury of the rat carotid artery and that estrogen modulates this proliferative response to injury. Conclusion: These results support the hypothesis that adventitial activation contributes to the vascular injury response and that estrogen reduces this contribution. [ABSTRACT FROM PUBLISHER]

Different substituents result in different changes in electron-photon spectra, and to reveal the relationship between substituents and spectra, a theoretical investigation was elaborated via quantum chemical calculations. Density functional theory and single excitation configuration interaction were respectively employed in optimizing geometric and electronic structures of ground and excited states, and the absorption and emission spectra were studied by time-dependent density functional theory methods. The results show that all the different substituents bring on different geometric and electronic structures of ground and excited states, different energies of frontier molecular orbitals as well as different pi-conjugated systems, the spectra change with all the differences, and relationships are brought out in this paper, which gives theoretical reference for identifying different derivatives from electron-photon spectra.