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Trefor Morgan Graham Barrett Yanling Zhang Daine Alcorn 《Clinical and experimental pharmacology & physiology》1991,18(2):123-126
1. The role of the macula densa in renin synthesis was studied using mice with one hydronephrotic kidney. 2. Renin synthesis was assessed by measurement of renal renin, renal mRNA for renin and plasma renin. 3. Sodium depletion stimulated mRNA and renal renin to a similar extent in the hydronephrotic and contralateral kidney. 4. Enalapril stimulated mRNA concentration in both kidneys but renal renin did not rise in the hydronephrotic kidney. 5. Propranolol did not alter the response to sodium depletion in either kidney. 6. The macula densa is not crucial for the stimulation of renin synthesis following sodium depletion. However, it may regulate renin production after mRNA synthesis, possibly by controlling the conversion of prorenin to renin. 相似文献
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Changes in mean arterial pressure predict degranulation of renomedullary interstitial cells 总被引:1,自引:0,他引:1
Maric C Harris PJ Alcorn D 《Clinical and experimental pharmacology & physiology》2002,29(12):1055-1059
1. Renomedullary interstitial cells (RMIC) are characterized by numerous intracellular granules thought to contain renal medullary antihypertensive substances. However, the nature of the trigger for RMIC degranulation remains to be elucidated. The present study examines the effects of acute alterations in mean arterial pressure (MAP) and medullary blood flow (MBF) on RMIC granulation. 2. Basal MAP and MBF in anaesthetized Sprague-Dawley rats (n = 4/group) were altered by intravenous infusions of vasoactive agents, including angiotensin II alone or with a nitric oxide (NO) synthase inhibitor (N-omega-nitro-l-arginine) or NO donor (sodium nitroprusside), noradrenaline and by carotid artery clamping. Following these treatments, kidneys were examined by electron microscopy and the absolute volume of granules in the renal medulla was calculated using unbiased stereological methods. 3. Acute increases in MAP, regardless of the treatment causing the increase, were associated with a reduction in the absolute volume of granules in the range of 42-67%. Regression analysis revealed that only increases in MAP, but not MBF, strongly predict RMIC degranulation. 4. Despite previous reports that changes in MBF activate renomedullary antihypertensive activity, we conclude that the change in MAP is an important determinant of the activity of the blood pressure-lowering mechanism of the renal medulla, with the assumption that the medullary lipids mediate the antihypertensive property of the renal medulla. 相似文献
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Malea M. Kneen Damien G. Harkin Lesley L. Walker Daine Alcorn P. J. Harris 《Brain structure & function》1999,200(1):117-121
Renal medullary interstitial cells are a prevalent and characteristic feature of the inner medulla of the kidney, but the
physiological significance of this is unclear. We have developed a method for imaging renal medullary interstitial cells in
situ by loading the cells with fluorescent dyes and monitoring their distribution using confocal microscopy. The pH-sensitive
probe 2’7’-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester was used as a marker of cytoplasmic volume
and therefore of cell morphology. Nile Red was used to demonstrate the presence of renal medullary interstitial cell lipid
droplets. Papillae were excised from 100 g Sprague-Dawley rats and loaded with the appropriate dye. The papillae were then
examined using a Leica TCS 4D confocal microscope and oil immersion lenses. Fluorescence was excited (488 nm) using an argon
laser and emission wavelengths above 515 nm collected using a long pass filter. Images of papillae loaded with 2’7’-bis-(carboxyethyl)-5-(and-6)-carboxyfluorescein
acetoxymethyl ester clearly demonstrate a ladder-like arrangement of renal medullary interstitial cells. More detailed examination
revealed the presence of cytoplasmic extensions that appear to make close contact with adjacent loops of Henle. Three-dimensional
reconstructions of serial sections revealed spiral arrangements in some ladders of renal medullary interstitial cells. Nile
Red-labelled lipid droplets of 0.5–1.0 μm diameter were located throughout the cytoplasm of renal medullary interstitial cells
and especially within the cytoplasmic extensions. These experiments highlight the ability of confocal microscopy to allow
investigation of renal medullary interstitial cells in situ.
Accepted: 3 December 1998 相似文献
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Lisiane Tuon PhD Clarissa M. Comim MSc Daine B. Fraga BSc Giselli Scaini BSc Gislaine T. Rezin MSc Bruna R. Baptista BSc Emilio L. Streck PhD Mariz Vainzof PhD João Quevedo MD PhD 《Muscle & nerve》2010,41(2):257-260
In this study we investigated energy metabolism in the mdx mouse brain.To this end, prefrontal cortex, cerebellum, hippocampus, striatum, and cortex were analyzed. There was a decrease in Complex I but not in Complex II activity in all structures. There was an increase in Complex III activity in striatum and a decrease in Complex IV activity in prefrontal cortex and striatum. Mitochondrial creatine kinase activity was increased in hippocampus, prefrontal cortex, cortex, and striatum. Our results indicate that there is energy metabolism dysfunction in the mdx mouse brain. Muscle Nerve, 2010 相似文献