Volume-sensitive chloride currents in primary cultures of human fetal vas deferens epithelial cells

Abstract

Using the patch-clamp technique, we have identified a large, outwardly rectifying, Cl--selective whole-cell current in primary cultures of human vas deferens epithelial cells. Whole-cell currents were time- and voltage-dependent and displayed inactivation following depolarising pulses >/= 60 mV. Currents were equally permeable to bromide (PBr/PCl = 1.05 +/- 0.04), iodide (PI/PCl = 1. 06 +/- 0.07) and Cl-, but significantly less permeable to gluconate (PGluc /PCl = 0.23 +/- 0.03). Currents spontaneously increased with time after establishing a whole-cell recording, but could be inhibited by exposure to a hypertonic bath solution which reduced inward currents by 68 +/- 4%. Subsequent exposure of the cells to a hypotonic bath solution led to a 418 +/- 110% increase in inward current, indicating that these currents are regulated by osmolarity. 4,4'-Diisothiocyanatostilbene-2,2'-disulphonic acid (100 microM) produced a rapid and reversible voltage-dependent block (60 +/- 5% and 10 +/- 7% inhibition of current, measured at +/- 60 mV, respectively). Dideoxyforskolin (50 microM) also reduced the volume-sensitive Cl- current, but with a much slower time course, by 41 +/- 13% and 32 +/- 16% (measured at +/- 60 mV, respectively). Tamoxifen (10 microM) had no effect on the whole-cell Cl- current. These results suggest that vas deferens epithelial cells possess a volume-sensitive Cl- conductance which has biophysical and pharmacological properties broadly similar to volume-sensitive Cl- currents previously described in a variety of cell types.

Biophysical and pharmacological characterization of hypotonically activated chloride currents in cortical astrocytes

“…Of note is that NPPB and niflumic acid appeared to produce a voltage-independent block of both outward and inward currents, whereas DIDS appeared to produce predominantly a voltage-dependent block of outward currents only. Such a voltage-dependent block by DIDS has been demonstrated previously for swelling-activated chloride currents in other cell types (Braun and Schulman, 1996;Ehring et al, 1994;Winpenny et al, 1996;Mitchell et al, 1997). We compared the percentage inhibition by each test drug in Figure 4D,E.…”

Cell Volume-Activated and Volume-Correlated Anion Channels in Mammalian Cells: Their Biophysical, Molecular, and Pharmacological Properties

“…An antiestrogen, tamoxifen, which is a known inhibitor of P-glycoprotein, was found to voltage-independently inhibit VSOR activity in a number of nonexcitable cells (Zhang et al, 1994;Tominaga et al, 1995b;Meyer and Korbmacher, 1996;Wondergem et al, 2001;Chen et al, 2002;Hélix et al, 2003;Yang et al, 2015) and colonic smooth muscle cells (Dick et al, 1999). In contrast, tamoxifen was ineffective in inhibiting VSOR in neuronal (Leaney et al, 1997;Inoue et al, 2005Zhang et al, 2011) and muscular (Voets et al, 1997) cells as well as in some epithelial cells (Winpenny et al, 1996;Mitchell et al, 1997b) and neutrophils (Ahluwalia, 2008b). In contrast, it is noted that tamoxifen blocks some cationic channels in neuronal cells (Allen et al, 1998;Hardy et al, 1998) and muscular cells (He et al, 2003) as well as voltage-gated Ca 2+ and K + channels in canine colonic myocytes at 10 mM (Dick et al, 1999).…”

Adenosine Stimulates Anion Secretion Across Cultured and Native Adult Human Vas Deferens Epithelia1

“…Human fetal vas deferens epithelial cells have been isolated and grown in culture to evaluate membrane ion permeabilities using whole-cell and isolated membrane patch techniques. Both Cl Ϫ [14] and K ϩ [15] channels are present in the cultured cells, although neither the contributions of these channels to epithelial transport nor control mechanisms has been identified.…”