Effect of nitric oxide synthase inhibition on intrarenal oxygenation as evaluated by blood oxygenation level-dependent magnetic resonance imaging.

Objective: To investigate the feasibility of studying renal effects of nitric oxide synthase inhibition (NOSi) in humans by blood oxygenation level-dependent (BOLD) MRI. Nitric oxide (NO) is known to play a key role in the pathophysiology of hypertension and previous reports suggest reduced bioavailability of NO in the kidneys of hypertensive rats and hence show reduced response to NOSi using BOLD MRI. Ability to perform similar studies in humans could potentially lead to detection of early changes before development of symptoms, and to monitor novel interventions targeted toward improved NO bioavailability.

Podocyte injury and glomerulosclerosis in hyperhomocysteinemic rats.

Background/aims: We previously reported that increase in plasma homocysteine (Hcys) levels by a 6-week methionine treatment produced remarkable glomerular injury. However, the mechanism by which hyperhomocysteinemia (hHcys) produces glomerular injury remains unknown. The present study was to observe when glomerular injury happens during hHcys and to explore the possible role of podocyte injury in the progression of glomerulosclerosis associated with hHcys.

Effects of 20-HETE on Na+ transport and Na+ -K+ -ATPase activity in the thick ascending loop of Henle.

Previous studies have indicated that 20-hydroxyeicosatetraenoic acid (20-HETE) inhibits Na+ transport in the medullary thick ascending loop of Henle (mTALH), but the mechanisms involved remain uncertain. The present study compared the effects of 20-HETE with those of ouabain and furosemide on intracellular Na+ concentration ([Na+]i), Na+ -K+ -ATPase activity, and 86Rb+ uptake, an index of Na+ transport, in mTALH isolated from rats. Ouabain (2 mM) increased, whereas furosemide (100 microM) decreased, [Na+]i in the mTALH of rats.

Early changes with diabetes in renal medullary hemodynamics as evaluated by fiberoptic probes and BOLD magnetic resonance imaging.

Objective: We sought to evaluate the influence of streptozotocin (STZ)-induced diabetes on renal outer medullary pO2 and blood flow by invasive microprobes and to demonstrate feasibility that blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) can monitor these changes.

Materials And Methods: A total of 60 Wistar-Furth rats were used. Diabetes was induced by STZ in 48.

Role of renal medullary heme oxygenase in the regulation of pressure natriuresis and arterial blood pressure.

Recent studies have demonstrated that inhibition of renal medullary heme oxygenase (HO) activity and carbon monoxide (CO) significantly decreases renal medullary blood flow and sodium excretion. Given the crucial role of renal medullary blood flow in the control of pressure natriuresis, the present study was designed to determine whether renal medullary HO activity and resulting CO production participate in the regulation of pressure natriuresis and thereby the long-term control of arterial blood pressure. In anesthetized Sprague-Dawley rats, increases in renal perfusion pressure induced significant elevations of CO concentrations in the renal medulla.

Effect of lifelong high- or low-salt intake on blood pressure, left ventricular mass and plasma insulin in Wistar rats.

Background: Salt restriction is recommended for hypertension treatment to reduce blood pressure, but its effect on some risk factors is still a matter of discussion. The aim of this study was to observe the effect of a long period of salt restriction or overload on blood pressure, left ventricular mass (LVM), kidney mass (KM), glucose tolerance, and plasma insulin.

Methods: Male Wistar rats were fed from weaning with a low-salt diet (LSD) or a high-salt diet (HSD) until 72 weeks of age.

Inhibition of the formation of EETs and 20-HETE with 1-aminobenzotriazole attenuates pressure natriuresis.

This study examined the effects of chronic blockade of the renal formation of epoxyeicosatrienoic acids and 20-hydroxyeicosatetraenoic acid with 1-aminobenzotriazole (ABT; 50 mg.kg(-1). day(-1) ip for 5 days) on pressure natriuresis and the inhibitory effects of elevations in renal perfusion pressure (RPP) on Na(+)-K(+)-ATPase activity and the distribution of the sodium/hydrogen exchanger (NHE)-3 in the proximal tubule of rats.

Elevated BSC-1 and ROMK expression in Dahl salt-sensitive rat kidneys.

This study compared the expression of enzymes and transport and channel proteins involved in the regulation of sodium reabsorption in the kidney of Dahl salt-sensitive (DS) and salt-resistant Brown-Norway (BN) and consomic rats (SS.BN13), in which chromosome 13 from the BN rat has been introgressed into the DS genetic background. The expression of the Na+/K+/2Cl- (BSC-1) cotransporter, Na+/H+ exchanger (NHE3), and Na+-K+-ATPase proteins were similar in the renal cortex of DS, BN, and SS.