Alterations in gene expression and microbiome composition upon calcium-sensing receptor deletion in the mouse esophagus.

The calcium-sensing receptor (CaSR), a G protein-coupled receptor, regulates Ca concentration in plasma by regulating parathyroid hormone secretion. In other tissues, it is reported to play roles in cellular differentiation and migration and in secretion and absorption. We reported previously that CaSR can be conditionally deleted in the mouse esophagus.

Ussing Chamber Methods to Study the Esophageal Epithelial Barrier.

The Ussing chamber was developed in 1949 by Hans Ussing and quickly became a powerful tool to study ion and solute transport in epithelia. The chamber has two compartments strictly separating the apical and basolateral sides of the tissue under study. The two sides of the tissue are connected via electrodes to a modified electrometer/pulse generator that allows measurement of electrical parameters, namely, transepithelial voltage, current, and resistance.

Calcium-sensing receptor deletion in the mouse esophagus alters barrier function.

Calcium-sensing receptor (CaSR) is the molecular sensor by which cells respond to small changes in extracellular Ca concentrations. CaSR has been reported to play a role in glandular and fluid secretion in the gastrointestinal tract and to regulate differentiation and proliferation of skin keratinocytes. CaSR is present in the esophageal epithelium, but its role in this tissue has not been defined.

Effects of chronic hypercapnia on ammonium transport in the mouse kidney.

Hypercapnia and subsequent respiratory acidosis are serious complications in many patients with respiratory disorders. The acute response to hypercapnia is buffering of H by hemoglobin and cellular proteins but this effect is limited. The chronic response is renal compensation that increases HCO reabsorption, and stimulates urinary excretion of titratable acids (TA) and NH .

Structural determinants of NH3 and NH4+ transport by mouse Rhbg, a renal Rh glycoprotein.

Renal Rhbg is localized to the basolateral membrane of intercalated cells and is involved in NH/NH transport. The structure of Rhbg is not yet resolved; however, a high-resolution crystal structure of AmtB, a bacterial homolog of Rh, has been determined. We aligned the sequence of Rhbg to that of AmtB and identified important sites of Rhbg that may affect transport.