Luis Gabriel Navar

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In recent years, the focus of interest on the role of the renin-angiotensin system (RAS) in the pathophysiology of hypertension and organ injury has changed to a major emphasis on the role of the local RAS in specific tissues. In the kidney, all of the RAS components are present and intrarenal angiotensin II (Ang II) is formed by independent multiple(More)
There has been an explosive growth of interest in the multiple interacting paracrine systems that influence renal microvascular function. This review first discusses the membrane activation mechanisms for renal vascular control. Evidence is provided that there are differential activating mechanisms regulating pre- and postglomerular arteriolar vascular(More)
Epoxygenase metabolites of arachidonic acid are produced by the kidney and have been implicated in the control of renal blood flow. This study examined the preglomerular actions of various epoxyeicosatrienoic acids (EET). By use of the in vitro blood-perfused juxtamedullary nephron preparation, interlobular and afferent arteriolar diameter responses to(More)
We reported previously that urinary angiotensinogen (UAGT) levels provide a specific index of the intrarenal renin-angiotensin system (RAS) status in angiotensin II-dependent hypertensive rats. To study this system in humans, we recently developed a human angiotensinogen ELISA. To test the hypothesis that UAGT is increased in hypertensive patients, we(More)
Intrarenal angiotensin II (Ang II) is regulated by several complex processes involving formation from both systemically delivered and intrarenally formed substrate, as well as receptor-mediated internalization. There is substantial compartmentalization of intrarenal Ang II, with levels in the renal interstitial fluid and in proximal tubule fluid being much(More)
The present study was undertaken to evaluate the renal responses to intra-arterial infusion (12.5 for 30 min of adrenomedullin (ADM) in denervated kidneys of anesthetized dogs (n = 8). Total renal blood flow (RBF) was measured with an electromagnetic flow probe, and two single-fiber laser-Doppler needle flow probes were used to measure(More)
Chronic elevations in circulating angiotensin II (AngII) levels produce sustained hypertension and increased intrarenal AngII contents through multiple mechanisms, which may include sustained or increased local production of AngII. This study was designed to test the hypothesis that chronic AngII infusion increases renal angiotensinogen mRNA and protein(More)
Chronic infusion of angiotensin (Ang) II leads to the development of hypertension and enhances intrarenal Ang II content to levels greater than can be explained from the circulating concentrations of the peptide. We previously reported that renal angiotensinogen (Ao) mRNA is enhanced in Ang II-dependent hypertension and may contribute to augmented(More)
The phenomenon of renal autoregulation is often thought to relate only to the manner in which the kidney responds to changes in arterial pressure. This review presents a more comprehensive description of the process based on the intrinsic renal vascular responses to changes in arterial pressure, venous pressure, ureteral pressure, and plasma colloid osmotic(More)
Collecting duct (CD) renin is stimulated by angiotensin (Ang) II, providing a pathway for Ang I generation and further conversion to Ang II. Ang II stimulates the epithelial sodium channel via the Ang II type 1 receptor and increases mineralocorticoid receptor activity attributed to increased aldosterone release. Our objective was to determine whether CD(More)