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M A Gray

Publications and source records attributed to M A Gray.

At least 19 recordsLinked to original sources
PubMed2006

Extracellular zinc stimulates a calcium-activated chloride conductance through mobilisation of intracellular calcium in renal inner medullary collecting duct cells.

We have used the perforated patch clamp and fura-2 fluorescence techniques to study the effect of extracellular Zn(2+) on whole-cell Ca(2+)-activated Cl(-) currents (I (CLCA)) in mouse inner medullary collecting duct cells (mIMCD-3). I (CLCA) was spontaneously active in 74% of cells under basal conditions and displayed time and voltage-independent kinetics and an outwardly rectifying current/voltage relationship (I/V). Addition of zinc chloride (10-400 microM) to the bathing solution resulted in a dose-dependent increase in I (CLCA) with little change in Cl(-) selectivity or biophysical characteristics, whereas gadolinium chloride (30 microM) and lanthanum chloride (100 microM) had no significant effect on the whole-cell current. Using fura-2-loaded mIMCD-3 cells, extracellular Zn(2+) (400 microM) stimulated an increase in intracellular Ca(2+) to an elevated plateau. The Zn(2+)-stimulated [Ca(2+)](i) increase was inhibited by thapsigargin (200 nM), the IP(3) receptor antagonist 2-aminoethoxydiphenyl borate (10 microM) and removal of bath Ca(2+). Pre-exposure to Zn(2+) (400 microM) markedly attenuated the ATP (100 microM)-stimulated [Ca(2+)](i) increase. These data are consistent with the hypothesis that extracellular Zn(2+) stimulates an increase in [Ca(2+)](i) by a release of calcium from thapsigargin/IP(3) sensitive stores. A possible physiological role for a divalent metal ion receptor, distinct from the extracellular Ca(2+)-sensing receptor, in IMCD cells is discussed.

Animals↗
PubMed2005

Using stable isotope analysis with telemetry or mark-recapture data to identify fish movement and foraging.

Information about animal movements has often been inferred from stable isotope analysis (SIA), but is dependent on animals assimilating site-specific isotopic signatures via diet. This potential weakness in ecological interpretation can be overcome by using other investigative tools that provide precise information about individual movement patterns. In this paper, we demonstrate the value of combining SIA with telemetry or mark-recapture data from trapping, electrofishing and remote detection of individuals to study the movement and feeding ecology of fishes in different habitats. In a fjord lake system in Newfoundland, Canada, juvenile Atlantic salmon delayed downstream migration (smolts) or actively moved into a large lake (parr) where they foraged for periods reflecting different life history strategies. In the Miramichi River (New Brunswick, Canada), SIA provided evidence of distinct foraging habitats (tributary versus large river). By tracking fish implanted with passive integrated transponder (PIT) tags, we distinguished between movements related to foraging versus seeking cool water refugia during high temperature events. Finally, site fidelity and limited mobility of slimy sculpin, a small benthic fish, was established where delta13C in muscle tissue showed a progressive enrichment downstream and where a median displacement of <10 m was estimated for sculpin tagged with PIT tags. Technological improvements have permitted non-destructive tissue sampling of wild fishes for SIA, and the tagging and remote detection of animals smaller than was previously possible. These advancements and the combination of investigative tools promise new insights into animal ecology.

Animals↗
PubMed2003

Kinetics and regulation of a Ca2+-activated Cl- conductance in mouse renal inner medullary collecting duct cells.

Using the whole cell patch-clamp technique, a Ca2+-activated Cl- conductance (CaCC) was transiently activated by extracellular ATP (100 microM) in primary cultures of mouse inner medullary collecting duct (IMCD) cells and in the mouse IMCD-K2 cell line. ATP also transiently increased intracellular Ca2+ concentration ([Ca2+]i) from 100 nM to peak values of approximately 750 nM in mIMCD-K2 cells, with a time course similar to the ATP-induced activation and decay of the CaCC. Removal of extracellular Ca2+ had no major effect on the peak Cl- conductance or the increase in [Ca2+]i induced by ATP, suggesting that Ca2+ released from intracellular stores directly activates the CaCC. In mIMCD-K2 cells, a rectifying time- and voltage-dependent current was observed when [Ca2+]i was fixed via the patch pipette to between 100 and 500 nM. Maximal activation occurred at approximately 1 microM [Ca2+]i, with currents losing any kinetics and displaying a linear current-voltage relationship. From Ca2+-dose-response curves, an EC50 value of approximately 650 nM at -80 mV was obtained, suggesting that under physiological conditions the CaCC would be near fully activated by mucosal nucleotides. Noise analysis of whole cell currents in mIMCD-K2 cells suggests a single-channel conductance of 6-8 pS and a density of approximately 5,000 channels/cell. In conclusion, the CaCC in mouse IMCD cells is a low-conductance, nucleotide-sensitive Cl- channel, whose activity is tightly coupled to changes in [Ca2+]i over the normal physiological range.

Animals↗
PubMed2002

Steady-state visually evoked potential topography during processing of emotional valence in healthy subjects.

The International Affective Picture System (IAPS) is increasingly used in brain imaging studies to examine emotional processes. This task allows valence and arousal content to be systematically investigated; however, previous studies have generally failed to select images that vary in one dimension as well as hold constant the variability on the other dimension. In addition, no studies have investigated the temporal structure associated with the conscious, ongoing processing of emotional stimuli following systematic selection of IAPS images. The aim of the present study was therefore to use steady-state probe topography (SSPT) to examine the steady-state visually evoked potentials (SSVEPs) associated with the processing of pleasant and unpleasant images low in arousal content. Seventy-five IAPS images, categorized as unpleasant, neutral, or pleasant, were presented to 16 healthy subjects while brain activity was recorded from 64 scalp sites. Analysis subtracted the activity associated with the presentation of neutral images from the activity associated with the presentation of pleasant as well as unpleasant images. Results demonstrate that both pleasant and unpleasant valence is associated with transient, widespread, and bilateral frontal SSVEP latency reductions. Unpleasant images were also associated with a transient bilateral anterior frontal amplitude decrease. Latency reductions are interpreted as increases in neural information processing speed, while amplitude reductions are interpreted in the current paper as analogous to an event-related desynchronisation commonly associated with the alpha bandwidth. These key findings support previous literature in terms of there being substantial overlap in frontal neural circuitry when the brain processes pleasant and unpleasant valence relative to neutral valence.

Adult↗
PubMed2001

The voltage-dependent Cl(-) channel ClC-5 and plasma membrane Cl(-) conductances of mouse renal collecting duct cells (mIMCD-3).

1. We have tested the hypothesis that the voltage-dependent Cl(-) channel, ClC-5 functions as a plasma membrane Cl(-) conductance in renal inner medullary collecting duct cells. 2. Full-length mouse kidney ClC-5 (mClC-5) was cloned and transiently expressed in CHO-K1 cells. Fast whole-cell patch-clamp recordings confirmed that mClC-5 expression produces a voltage-dependent, strongly outwardly rectifying Cl(-) conductance that was unaffected by external DIDS. 3. Slow whole-cell recordings, using nystatin-perforated patches from transfected CHO-K1 cells, also produced voltage-dependent Cl(-) currents consistent with ClC-5 expression. However, under this recording configuration an endogenous DIDS-sensitive Ca(2+)-activated Cl(-) conductance was also evident, which appeared to be activated by green fluorescent protein (GFP) transfection. 4. A mClC-5-GFP fusion protein was transiently expressed in CHO-K1 cells; confocal laser scanning microscopy (CLSM) showed localization at the plasma membrane, consistent with patch-clamp experiments. 5. Endogenous expression of mClC-5 was demonstrated in mouse renal collecting duct cells (mIMCD-3) by RT-PCR and by immunocytochemistry. 6. Using slow whole-cell current recordings, mIMCD-3 cells displayed three biophysically distinct Cl(-)-selective currents, which were all inhibited by DIDS. However, no cells exhibited whole-cell currents that had mClC-5 characteristics. 7. Transient transfection of mIMCD-3 cells with antisense mClC-5 had no effect on the endogenous Cl(-) conductances. Transient transfection with sense mClC-5 failed to induce the Cl(-) conductance seen in CHO-K1 cells but stimulated levels of the endogenous Ca(2+)-activated Cl(-) conductance 24 h post-transfection. 8. Confocal laser scanning microscopy of mIMCD-3 cells transfected with mClC-5-GFP showed that the protein was absent from the plasma membrane and was instead localized to acidic endosomal compartments. 9. These data discount a major role for ClC-5 as a plasma membrane Cl(-) conductance in mIMCD-3 cells but suggest a role in endosomal function.

Algorithms↗
PubMed2001

Regulation of an outwardly rectifying chloride conductance in renal epithelial cells by external and internal calcium.

We have used perforated patch clamp and Fura-2 microfluorescence measurements to study Ca(2+)-activated Cl- currents in cultured mouse renal inner medullary collecting duct cells (mIMCD-3). The conductance was spontaneously active under resting conditions and whole cell currents were time and voltage-independent with an outwardly rectifying current-voltage relationship. The channel blockers DIDS, niflumic acid, glybenclamide and NPPB reversibly decreased the basal currents, whereas the sulfhydryl agent, DTT produced an irreversible inhibition. Increasing or decreasing extracellular calcium produced parallel changes in the size of the basal currents. Variations in external Ca2+ were associated with corresponding changes in free cytosolic Ca2+ concentration. Increasing cytosolic Ca2+ by extracellular ATP or ionomycin, further enhanced Cl- conductance, with whole cell currents displaying identical biophysical properties to the basal currents. However, the agonist-stimulated currents were now increased by DTT exposure, but still inhibited by the other channel blockers. Using RT-PCR, three distinct mRNA transcripts belonging to the CLCA family of Ca(2+)-activated Cl- channel proteins were identified, two of which represent novel sequences. Whether different channels underlie the basal and agonist-stimulated currents in mIMCD-3 cells is unclear. Our findings establish a novel link between alterations in external and internal Ca2+ and the activity of Ca(2+)-activated Cl- transport in these cells.

Adenosine Triphosphate↗
PubMed2001

Correction of delF508-CFTR activity with benzo(c)quinolizinium compounds through facilitation of its processing in cystic fibrosis airway cells.

A number of genetic diseases, including cystic fibrosis, have been identified as disorders of protein trafficking associated with retention of mutant protein within the endoplasmic reticulum. In the presence of the benzo(c)quinolizinium drugs, MPB-07 and its congener MPB-91, we show the activation of cystic fibrosis transmembrane conductance regulator (CFTR) delF508 channels in IB3-1 human cells, which express endogenous levels of delF508-CFTR. These drugs were without effect on the Ca(2+)-activated Cl- transport, whereas the swelling-activated Cl- transport was found altered in MPB-treated cells. Immunoprecipitation and in vitro phosphorylation shows a 20% increase of the band C form of delF508 after MPB treatment. We then investigated the effect of these drugs on the extent of mislocalisation of delF508-CFTR in native airway cells from cystic fibrosis patients. We first showed that delF508 CFTR was characteristically restricted to an endoplasmic reticulum location in approximately 80% of untreated cells from CF patients homozygous for the delF508-CFTR mutation. By contrast, 60-70% of cells from non-CF patients showed wild-type CFTR in an apical location. MPB-07 treatment caused dramatic relocation of delF508-CFTR to the apical region such that the majority of delF508/delF508 CF cells showed a similar CFTR location to that of wild-type. MPB-07 had no apparent effect on the distribution of wild-type CFTR, the apical membrane protein CD59 or the ER membrane Ca(2+),Mg-ATPase. We also showed a similar pharmacological effect in nasal cells freshly isolated from a delF508/G551D CF patient. The results demonstrate selective redirection of a mutant membrane protein using cell-permeant small molecules of the benzo(c)quinolizinium family and provide a major advance towards development of a targetted drug treatment for cystic fibrosis and other disorders of protein trafficking.

Calcium↗
PubMed2001

150 mM HCO3(-)--how does the pancreas do it? Clues from computer modelling of the duct cell.

Cystic fibrosis (CF) takes its name from the pathological changes that occur in the pancreas. Cystic fibrosis transmembrane conductance regulator (CFTR) is highly expressed in the pancreatic ductal epithelium and plays a key role in ductal HCO(3)(-) secretion. In humans, the pancreatic duct secretes near isotonic NaHCO(3). Experimental data suggests that HCO(3)(-) secretion occurs via apical Cl(-)/HCO(3)(-) exchangers working in parallel with Cl(-) channels (CFTR and calcium activated chloride channels, CaCC). Programming the currently available experimental data into our computer model (based on network thermodynamics) shows that while the anion exchanger/Cl(-) channel mechanism will produce a relatively large volume of a HCO(3)(-)-rich fluid, it can only raise the luminal HCO(3)(-) concentration up to about 70 mM. To achieve secretion of about 150 mM NaHCO(3) it is necessary to modulate the properties of the apical membrane transporters as the secreted fluid flows down the ductal system. On the basis of our computer simulations, we propose that HCO(3)(-) secretion occurs mainly via the exchanger in duct segments near the acini (luminal HCO(3)(-) concentration up to about 70 mM), but mainly via channels further down the ductal tree (raising luminal HCO(3)(-) to about 150 mM). We speculate that the switch between these two secretory mechanisms is controlled by a series of luminal signals (e.g. pH, HCO(3)(-) concentration) acting on the apical membrane transporters in the duct cell.

Animals↗
PubMed2001

Functional interactions of HCO3- with cystic fibrosis transmembrane conductance regulator.

Disruption of normal cystic fibrosis transmembrane conductance regulator- (CFTR)-mediated Cl(-) transport is associated with cystic fibrosis (CF). CFTR is also required for HCO(3)(-) transport in many tissues such as the lungs, gastro-intestinal tract, and pancreas, although the exact role CFTR plays is uncertain. Given the importance of CFTR in HCO(3)(-) transport by so many CF-affected organ systems, it is perhaps surprising that relatively little is known about the interactions of HCO(3)(-) ions with CFTR. We have used patch clamp recordings from native pancreatic duct cells to study HCO(3)(-) permeation and interaction with CFTR. Ion selectivity studies shows that CFTR is between 3-5 times more selective for Cl(-) over HCO(3)(-). In addition, extracellular HCO(3)(-) has a novel inhibitory effect on cAMP-stimulated CFTR currents carried by Cl(-). The block by HCO(3)(-) was rapid, relatively independent of voltage and occurred over the physiological range of HCO(3)(-) concentrations. These data show that luminal HCO(3)(-) acts as a potent regulator of CFTR, and suggests that inhibition involves an external anion-binding site on the channel. This work has implications not only for elucidating mechanisms of HCO(3)(-) transport in epithelia, but also for approaches used to treat CF.

Animals↗
PubMed2000

The swelling-activated anion conductance in the mouse renal inner medullary collecting duct cell line mIMCD-K2.

Swelling-activated Cl(-) currents (I(Cl,swell)) have been characterized in a mouse renal inner medullary collecting duct cell line (mIMCD-K2). Currents activated by exposing the cells to hypotonicity exhibited characteristic outward rectification and time- and voltage-dependent inactivation at positive potentials and showed an anion selectivity of I(-) > Br(-) > Cl(-) > Asp(-). NPPB (100 microm) inhibited the current in a voltage independent manner, as did exposure to 10 microm tamoxifen and 500 microm niflumic acid (NFA). In contrast, DIDS (100 microm) blocked the current with a characteristic voltage dependency. These characteristics of I(Cl, swell) in mIMCD-K2 cells are essentially identical to those of heterologously expressed cardiac CLC-3. A defining feature of CLC-3 is that activation of PKC by PDBu inhibits the conductance. In mIMCD-K2 cells preincubation with PDBu (100 nm) prevented the activation of I(Cl,swell) by hypotonicity. However, PDBu inhibition of I(Cl,swell) was reversed after PDBu withdrawal, but this was refractory to subsequent PDBu inhibition. Activation of either the cystic fibrosis transmembrane conductance regulator (CFTR) or Ca(2+) activated Cl(-) conductance (CaCC), which are coexpressed in mIMCD-K2 cells prior to PDBu treatment, abolished the PDBu inhibition of I(Cl,swell). Control of I(Cl,swell) by PKC therefore depends on the physiological status of the cell. In intact mIMCD-K2 layers in Ussing chambers, forskolin stimulation of an inward short-circuit current (due to transepithelial Cl(-) secretion via apical CFTR) was inhibited by cell swelling upon hypotonic exposure at the basolateral surface. Activation of I(Cl,swell) is therefore capable of regulating transepithelial Cl(-) secretion and suggests that I(Cl,swell) is located at the basolateral membrane. PDBu exposure prior to or during hypotonic challenge was ineffective in reversing the swelling-activated inhibition of Cl(-) secretion, but tamoxifen (100 microm) abolished the hypotonic inhibition of forskolin-stimulated short-circuit current (I(sc)). RT-PCR analysis confirmed expression of mRNA for members of the CLC family, including both CLC-2 and 3, in the mIMCD-K2 cell line.

Animals↗
PubMed2000

HCO3- transport in a mathematical model of the pancreatic ductal epithelium.

We have used computer modeling to investigate how pancreatic duct cells can secrete a fluid containing near isotonic (approximately 140 mM) NaHCO3. Experimental data suggest that NaHCO3 secretion occurs in three steps: (i) accumulation of HCO3- across the basolateral membrane of the duct cell by Na(HCO3)n cotransporters, Na+/H+ exchangers and proton pumps; (ii) secretion of HCO3- across the luminal membrane on Cl-/HCO3- antiporters operating in parallel with Cl- channels; and (iii) diffusion of Na+ through the paracellular pathway. Programming the currently available experimental data into our computer model shows that this mechanism for HCO3- secretion is deficient in one important respect. While it can produce a relatively large volume of a HCO3(-)-rich fluid, it can only raise the luminal HCO3- concentration up to about 70 mM. To achieve secretion of 140 mM NaHCO3 by the model it is necessary to: (i) reduce the conductive Cl- permeability and increase the conductive HCO3- permeability of the luminal membrane of the duct cell, and (ii) reduce the activity of the luminal Cl-/HCO3- antiporters. Under these conditions most of the HCO3- is secreted via a conductive pathway. Based on our data, we propose that HCO3- secretion occurs mainly by the antiporter in duct segments near the acini (luminal HCO3- concentration up to approximately 70 mM), but mainly via channels further down the ductal tree (raising luminal HCO3- to approximately 140 mM).

Animals↗
PubMed2000

Regulation of a hyperpolarization-activated chloride current in murine respiratory ciliated cells.

1. The properties of a hyperpolarization-activated Cl- current (Ihyp-act) in murine ciliated respiratory cells have been studied using whole cell patch clamping. 2. The current-voltage relationship was inwardly rectifying which was due to voltage-dependent gating of the channel. 3. Inward current was markedly sensitive to the extracellular Cl- concentration, an effect that was not related to changes in transmembrane Cl- gradient. Decreasing extracellular Cl- concentration to 6 mM caused a 70 % reduction in inward current with the dose-response relationship exhibiting a Hill coefficient of approximately 2.0 and an IC50 of 29 mM. 4. External anion replacement gave a selectivity sequence of Br- >= I- > Cl- > gluconate = aspartate. The more permeant halides significantly increased current density while the less permeant anions decreased current density, indicating that an extracellular anion is important for channel activity. 5. The conductance was unaffected by exposure to anisotonic pipette solutions or to increases in intracellular cAMP; however, current density was reduced dose dependently by increases in intracellular calcium concentration from 0.1 to 0.5 microM. These results indicate that Ihyp-act is unlikely to be involved in either volume regulation or cAMP/Ca2+-stimulated fluid secretion. 6. Decreasing extracellular pH to 5.0 irreversibly inhibited Ihyp-act. However, the current was fully active over the pH range 5.4-9.0 making it unlikely that it is modulated by extracellular pH under physiological conditions. 7. We speculate that Ihyp-act may have a role in basal Cl- absorption, acting as a Cl- sensor to maintain optimal volume and composition of airway surface liquid.

Adenosine Triphosphate↗
PubMed2000

Ca2+ and cAMP-activated Cl- conductances mediate Cl- secretion in a mouse renal inner medullary collecting duct cell line.

1. The nature of Cl- conductance(s) participating in transepithelial anion secretion by renal inner medullary collecting duct (IMCD, mIMCD-K2 cell line) was investigated. 2. Extracellular ATP (100 microM) stimulated a transient increase in both whole-cell Cl- conductance and intracellular free Ca2+. In contrast, ionomycin (10-100 nM) caused a sustained increase in whole-cell Cl- conductance. Pre-loading cells with the Ca2+ buffer BAPTA abolished the ATP-dependent responses and delayed the onset of the increase observed with ionomycin. 3. The Ca2+-activated whole-cell Cl- current stimulated by ATP (peak) and ionomycin (maximal) displayed (i) a linear steady-state current-voltage relationship and (ii) time and voltage dependence with slow activation at +80 mV and slow inactivation at -80 mV. In BAPTA-loaded cells, ionomycin-elicited whole-cell currents exhibited pronounced outward rectification with time-dependent activation/inactivation. 4. Ca2+-activated and forskolin-activated Cl- conductances co-exist since ATP activation of whole-cell current occurred during a maximal stimulation by forskolin in single cell recordings. 5. In IMCD epithelial layers, ATP and ionomycin stimulated an inward short circuit current (Isc) dependent upon basal medium Na+ and Cl-/HCO3- but independent of the presence of apical bathing medium Na+ and Cl-/HCO3-. This was identical to forskolin stimulation and consistent with transepithelial anion secretion. 6. PCR amplification of reverse-transcribed mRNA using gene-specific primers demonstrated expression of both cystic fibrosis transmembrane conductance regulator (CFTR) mRNA and Ca2+-activated Cl- channel (mCLCA1) mRNA in mIMCD-K2 cells. 7. Ca2+ and forskolin-activated Cl- conductances participate in anion secretion by IMCD.

Adenosine Triphosphate↗
PubMed2000

Cystic fibrosis transmembrane conductance regulator currents in guinea pig pancreatic duct cells: inhibition by bicarbonate ions.

BACKGROUND & AIMS: Cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels play an important role in HCO(3)(-) secretion by pancreatic duct cells (PDCs). Our aims were to characterize the CFTR conductance of guinea pig PDCs and to establish whether CFTR is regulated by HCO(3)(-). METHODS: PDCs were isolated from small intralobular and interlobular ducts, and their Cl(- )conductance was studied using the whole-cell patch clamp technique. RESULTS: Activation of a typical CFTR conductance by adenosine 3',5'-cyclic monophosphate (cAMP) was observed in 114 of 204 cells (56%). A larger (10-fold), time- and voltage-dependent Cl(-) conductance was activated in 39 of 204 cells (19%). Secretin had a similar effect. Coexpression of both conductances in the same cell was observed, and both conductances had similar anion selectivity and pharmacology. Extracellular HCO(3)(-) caused a dose-dependent inhibition of both currents (K(i), approximately 7 mmol/L), which was independent of intracellular and extracellular pH, and the PCO(2) and CO(3)(2-) content of the bathing solutions. CONCLUSIONS: Two kinetically distinct Cl(-) conductances are activated by cAMP in guinea pig PDCs. Because these conductances are coexpressed and exhibit similar characteristics (anion selectivity, pharmacology, and HCO(3)(-) inhibition), we conclude that CFTR underlies them both. The inhibition of CFTR by HCO(3)(-) has implications for the current model of pancreatic ductal HCO(3)(-) secretion.

Animals↗
PubMed2000

Bradykinin regulation of salt transport across mouse inner medullary collecting duct epithelium involves activation of a Ca(2+)-dependent Cl(-) conductance.

The mechanism by which bradykinin regulates renal epithelial salt transport has been investigated using a mouse inner medullary renal collecting duct cell-line mIMCD-K2. Using fura-2 loaded mIMCD-K2 cells bradykinin (100 nM) has been shown to induce a transient increase in intracellular Ca(2+) via activation of bradykinin B2 receptors localized to both the apical and basolateral epithelial cell surfaces. In mIMCD-K2 epithelial cell-layers clamped in Ussing chambers, 100 nM bradykinin via apical and basolateral bradykinin B2 receptors stimulated a transient increase in inward short-circuit current (I:(sc)) of similar duration to the increase in intracellular Ca(2+). Replacements of the bathing solution Na(+) by the impermeant cation, N-methyl-D-glucamine and of Cl(-) and HCO(3)(-) by the impermeant anion gluconate at either the apical (no reduction) or basal bathing solutions (abolition of the response) are consistent with the bradykinin-stimulated increase in inward I:(sc) resulting from basal to apical Cl(-) (anion) secretion. Using the slow whole cell configuration of the patch-clamp technique, bradykinin was shown to activate a transient Cl(-) selective whole cell current which showed time-dependent activation at positive membrane potentials and time-dependent inactivation at negative membrane potentials. These currents were distinct from those activated by forskolin (CFTR), but identical to those activated by exogenous ATP and are therefore consistent with bradykinin activation of a Ca(2+)-dependent Cl(-) conductance. The molecular identity of the Ca(2+)-dependent Cl(-) conductance has been investigated by an RT - PCR approach. Expression of an mRNA transcript with 96% identity to mCLCA1/2 was confirmed, however an additional but distinct mRNA transcript with only 81% of the identity to mCLCA1/2 was identified.

Animals↗