Left Ventricular Systolic Dysfunction in NBCe1-B/C-Knockout Mice.

Congenital proximal renal tubular acidosis (pRTA) is a rare systemic disease caused by mutations in the gene that encodes the electrogenic sodium bicarbonate cotransporter, NBCe1. The major NBCe1 protein variants are designated NBCe1-A, NBCe1-B, and NBCe1-C. NBCe1-A expression is kidney-specific, NBCe1-B is broadly expressed and is the only NBCe1 variant expressed in the heart, and NBCe1-C is a splice variant of NBCe1-B that is expressed in the brain.

NBCe1-B/C-knockout mice exhibit an impaired respiratory response and an enhanced renal response to metabolic acidosis.

The sodium-bicarbonate cotransporter (NBCe1) has three primary variants: NBCe1-A, -B and -C. NBCe1-A is expressed in renal proximal tubules in the cortical labyrinth, where it is essential for reclaiming filtered bicarbonate, such that NBCe1-A knockout mice are congenitally acidemic. NBCe1-B and -C variants are expressed in chemosensitive regions of the brainstem, while NBCe1-B is also expressed in renal proximal tubules located in the outer medulla.

Revisiting the Role of Ser982 Phosphorylation in Stoichiometry Shift of the Electrogenic Na/HCO Cotransporter NBCe1.

In most cell types and heterologous expression systems, the electrogenic sodium-bicarbonate cotransporter NBCe1 operates with a 1Na-2HCO stoichiometry that, given typical transmembrane electrochemical gradients, promotes Na+ and HCO influx. However, NBCe1 in the kidney mediates HCO efflux (HCO reabsorption), a direction that has been predicted to be favored only if NBCe1 operates with a 1:3 stoichiometry. The phosphorylation state of Ser982 in the cytosolic carboxy-terminal domain of NBCe1 has been reported to be a key determinant of the transporter stoichiometry, with non-phosphorylated Ser982 favoring a 1:3 stoichiometry.

Intestinal Transit Time and Cortisol-Mediated Stress in Zebrafish.

Intestinal motility, the spontaneous and rhythmic smooth muscle contraction, is a complex process that is regulated by overlapping and redundant regulatory mechanisms. Primary regulators intrinsic to the gastrointestinal tract include interstitial cells of Cajal, enteric neurons, and smooth muscle cells. Extrinsic primary regulators include the autonomic nervous system, immune system, and the endocrine system.

Cyanide-Nitroprusside Colorimetric Assay: A Rapid Colorimetric Screen for Urinary Cystine.

Background: Cystinuria is an autosomal recessive disorder resulting in poor proximal tubule reabsorption of cystine in the nephron, increasing the risk of cystine stone formation. A fast, inexpensive assay to screen for urinary cystine is needed because cystine stones are difficult to noninvasively differentiate from more common calcium-containing ones. Tandem mass spectrometry (MS/MS) is sensitive and specific but is labor-intensive and costly.