3 results on '"Romero, Cesar A."'
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2. Role of the distal nephron on salt homeostasis and blood pressure regulation
- Author
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Lim, Heeju and Romero, Cesar A.
- Subjects
Sal ,Ciencias Médicas ,ENaC ,Salt ,Hypertension ,Hipertensión ,Pendrin ,Túbulo conector ,Connecting tubule ,Distal nephron ,Nefrón distal ,Pendrina - Abstract
The distal nephron is constituted by the distal convoluted tubule, connecting tubule, and collecting duct. It is also known as “aldosterone sensitive distal nephron” (ASDN) because it is the anatomical substrate for the classical aldosterone effect of reabsorbing sodium and excreting potassium. This region is thought to perform the “fine-tuning” of ions and water homeostasis to balance intake levels. Consequently, this segment has significant impacts on sodium reabsorption and blood pressure regulation, illustrated by some genetic alteration effects such as Liddle syndrome, pseudohypoaldosteronism, and Pendred syndrome. In this mini-review, we explore the ASDN structure and the main channels that participate in sodium and chloride reabsorption. The epithelial sodium channel (ENaC) and the interchanger chloride-bicarbonate transporter (pendrin) are reviewed in detail as the main drivers of salt reabsorption in this segment. We also provide an introduction to crosstalk communication between the connecting tubule and the afferent arteriole as a feedback mechanism to integrate tubular sodium handling in this segment, in addition to its role in renal hemodynamics autoregulation., El nefrón distal está constituido por el túbulo contorneado distal, túbulo conector, y el conducto colector. También es conocido como el “nefrón distal sensible a aldosterona” (NDSA) ya que es el sustrato anatómico del efecto clásico de la aldosterona de reabsorción de sodio y excreción de potasio. Se piensa que esta región lleva a cabo el “ajuste fino” de la homeostasis de los iones y agua para balancear los niveles de ingesta. En consecuencia, este segmento tiene impactos significativos en la reabsorción de sodio y regulación de la presión sanguínea, ilustrado por algunos efectos de alteración genética tales como el síndrome de Liddle, seudohipoaldosteronismo y síndrome de Pendred. En esta minirevisión, exploramos la estructura del NDSA y los principales canales que participan en la reabsorción de sodio y cloruro. El canal de sodio epitelial (ENaC) y el intercambiador cloruro-bicarbonato (pendrina) son revisados en detalle como los principales responsables de la reabsorción de sal en este segmento. También se provee una introducción de la comunicación cruzada entre el túbulo conector y la arteriola aferente como un mecanismo de retroalimentación para integrar el manejo del sodio tubular en este segmento, además de su rol en la autorregulación hemodinámica renal., Sociedad Argentina de Fisiología
- Published
- 2021
3. THE RENAL PHYSIOLOGY OF PENDRIN-POSITIVE INTERCALATED CELLS.
- Author
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Wall, Susan M., Verlander, Jill W., and Romero, Cesar A.
- Abstract
Intercalated cells (ICs) are found in the connecting tubule and the collecting duct. Of the three IC subtypes identified, type B intercalated cells are one of the best characterized and known to mediate Cl
- absorption and HCO3 secretion, largely through the anion exchanger pendrin. This exchanger is thought to act in tandem with the Na+ dependent Cl- /HCO3 exchanger, NDCBE, to mediate net NaCl absorption. Pendrin is stimulated by angiotensin II and aldosterone administration via the angiotensin type 1a and the mineralocorticoid receptors, respectively. It is also stimulated in models of metabolic alkalosis, such as with NaHCO3 administration. In some rodent models, pendrin-mediated HCO- 3 secretion modulates acid-base balance. However, of probably more physiological or clinical significance is the role of these pendrin-positive ICs in blood pressure regulation, which occurs, at least in part, through pendrin-mediated renal Cl- absorption, as well as their effect on the epithelial Na+ channel, ENaC. Aldosterone stimulates ENaC directly through principal cell mineralocorticoid hormone receptor (ligand) binding and also indirectly through its effect on pendrin expression and function. In so doing, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. In addition to its role in Na+ and Cl- balance, pendrin affects the balance of other ions, such as K+ and I- . This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contribution of pendrin-positive ICs in the kidney to distal nephron function and blood pressure. [ABSTRACT FROM AUTHOR]- Published
- 2020
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