Contractile force is enhanced in Aortas from pendrin null mice due to stimulation of angiotensin II-dependent signaling.

Pendrin is a Cl-/HCO3- exchanger expressed in the apical regions of renal intercalated cells. Following pendrin gene ablation, blood pressure falls, in part, from reduced renal NaCl absorption. We asked if pendrin is expressed in vascular tissue and if the lower blood pressure observed in pendrin null mice is accompanied by reduced vascular reactivity.

Cholinergic regulation of epithelial sodium channels in rat alveolar type 2 epithelial cells.

We and others have shown that epithelial Na(+) channels (ENaC) in alveolar type 2 (AT2) cells are activated by β2 agonists, steroid hormones, elevated oxygen tension, and by dopamine. Although acetylcholine receptors (AChRs) have been previously described in the lung, there are few reports of whether cholinergic agonists alter sodium transport in the alveolar epithelium. Therefore, we investigated how cholinergic receptors regulate ENaC activity in primary cultures of rat AT2 cells using cell-attached patch-clamp recordings to assess ENaC activity.

Protein-protein interaction between cPLA2 and splice variants of alpha-subunit of BK channels.

Altering the splice variant composition of large-conductance Ca(2+)-activated potassium (BK) channels can alter their activity and apparent sensitivity to Ca(2+) and other regulators of activity. We hypothesized that differences in the responsiveness to arachidonic acid of GH3 and GH4 cells was due to a difference in two splice variants, one present in GH3 cells and the other in GH4 cells. The sequences of the two splice variants differ from one another in several ways, but the largest difference is the presence or absence of 27 amino acids in the COOH terminus of the BK alpha-subunit.

Dopamine regulation of amiloride-sensitive sodium channels in lung cells.

Dopamine increases lung fluid clearance. This is partly due to activation of basolateral Na-K-ATPase. However, activation of Na-K-ATPase by itself is unlikely to produce large changes in transepithelial transport.

Regulation of Na+ channels in lung alveolar type II epithelial cells.

Amiloride-sensitive sodium channels in the lung play an important role in lung fluid balance. Particularly in the alveoli, sodium transport is closely regulated to maintain an appropriate fluid layer on the surface of the alveoli. Alveolar type II cells appear to play an important role in this sodium transport.

Steroids and exogenous gamma-ENaC subunit modulate cation channels formed by alpha-ENaC in human B lymphocytes.

Previous studies using whole-cell recording methods suggest that human B lymphocytes express an amiloride-sensitive, sodium-permeable channel. The present studies aim to determine whether this channel has biophysical properties and a molecular structure related to the alpha, beta, and gamma subunits of the epithelial sodium channel (ENaC). Reverse transcriptase polymerase chain reaction and Northern blots showed that human B lymphocytes express messages for both alpha- and beta- but not gamma-ENaC.

Expression of highly selective sodium channels in alveolar type II cells is determined by culture conditions.

Alveolar fluid clearance in the developing and mature lungs is believed to be mediated by some form of epithelial Na channels (ENaC). However, single-channel studies using isolated alveolar type II (ATII) cells have failed to demonstrate consistently the presence of highly selective Na+ channels that would be expected from ENaC expression. We postulated that in vitro culture conditions might be responsible for alterations in the biophysical properties of Na+ conductances observed in cultured ATII cells.