Hirota, Simon, Nancy Trimble, Evi Pertens, and Luke J. Janssen. Intracellular Cl fluxes play a novel role in Ca handling in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 290: L1146–L1153, 2006. First published January 20, 2006; doi:10.1152/ajplung.00393.2005.—Intracellular Ca is actively sequestered into the sarcoplasmic reticulum (SR), whereas the release of Ca from the SR can be tr...

Whether intracellular Ca(2+) cycling dynamics regulate cardiac pacemaker cell function on a beat-to-beat basis remains unknown. Here we show that under physiological conditions, application of low concentrations of caffeine (2-4 mM) to isolated single rabbit sinoatrial node cells acutely reduces their spontaneous action potential cycle length (CL) and increases Ca(2+) transient amplitude for se...

Ca(2+)-activated Cl channels (Cl(Ca)Cs) are an important class of anion channels that are opened by increases in cytosolic [Ca(2+)]. Here, we examine the mechanisms of anion permeation through Cl(Ca)Cs from Xenopus oocytes in excised inside-out and outside-out patches. Cl(Ca)Cs exhibited moderate selectivity for Cl over Na: P(Na)/P(Cl) = 0.1. The apparent affinity of Cl(Ca)Cs for Cl was low: K(...

This study concerns effects on water-borne lead from combinations of chlorine (CL) or chloramines (CA) with fluosilicic acid (FSA) or sodium fluoride (NaF). CL is known to corrode brass, releasing lead from plumbing devices. It is known that CA and CL in different ratios with ammonia (NH) mobilize copper from brass, which we have found also enhances elution of lead from leaded brass alloys. Pha...

Pulmonary artery smooth muscle cells (PASMCs) are more depolarized and display higher Ca(2+) levels in pulmonary hypertension (PH). Whether the functional properties and expression of Ca(2+)-activated Cl- channels (Cl(Ca)), an important excitatory mechanism in PASMCs, are altered in PH is unknown. The potential role of Cl(Ca) channels in PH was investigated using the monocrotaline (MCT)-induced...

Two families of proteins, the bestrophins (Best) and the recently cloned TMEM16 proteins (anoctamin, Ano), recapitulate properties of Ca(2+)-activated Cl(-) currents. Best1 is strongly expressed in the retinal pigment epithelium and could have a function as a Ca(2+)-activated Cl(-) channel as well as a regulator of Ca(2+) signaling. It is also present at much lower levels in other cell types in...

The activation of Ca(2+)-dependent Cl(-) channels during norepinephrine-induced contraction of vascular smooth muscle was suggested to depolarize cell membrane and to increase Ca(2+) entry. Hypertension and ageing are associated with altered Ca(2+) handling including possible activation of Ca(2+)-dependent Cl(-) channels. Our study was aimed to determine Ca(2+)-dependent Cl(-) channels contribu...

Xenopus oocytes express several different Ca-activated Cl currents that have different waveforms and biophysical properties. We compared the stimulation of Ca-activated Cl currents measured by two-microelectrode voltage clamp with the Ca transients measured in the same cell by confocal microscopy and Ca-sensitive fluorophores. The purpose was to determine how the amplitude and/or spatio-tempora...

Vertebrate photoreceptors are highly polarized sensory cells in which several different ionic currents have been characterized. In the present study we used whole cell voltage-clamp and optical imaging techniques, the former combined with microsurgical manipulations, and simultaneous recording of membrane current and intracellular calcium signals to investigate the spatial distribution of ion c...

Molecular identification of the Ca(2+)-dependent chloride channel TMEM16A (ANO1) provided a fundamental step in understanding Ca(2+)-dependent Cl(-) secretion in epithelia. TMEM16A is an intrinsic constituent of Ca(2+)-dependent Cl(-) channels in cultured epithelia and may control salivary output, but its physiological role in native epithelial tissues remains largely obscure. Here, we demonstr...