Mucosal histamine inhibits Na absorption and stimulates Cl secretion across equine tracheal epithelium

1991 ◽  
Vol 261 (6) ◽  
pp. L456-L461 ◽  
Author(s):  
G. J. Tessier ◽  
T. R. Traynor ◽  
M. S. Kannan ◽  
S. M. O'Grady
Keyword(s):  
Apical Membrane ◽  
Short Circuit ◽  
Membrane Surface ◽  
Short Circuit Current ◽  
Ringer Solution ◽  
Tracheal Epithelium ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
Subsequent Addition ◽  
Over Time

When the equine tracheal epithelium is mounted in Ussing chambers and bathed in plasma-like Ringer solution, the tissue generates a lumen-negative transepithelial potential (PD) of 22 mV and a short-circuit current (Isc) of 70-200 microA/cm2. Mucosal addition of 10 microM histamine produces a transient increase in the Isc followed by a return to baseline or below. Mucosal addition of 2 microM diphenhydramine inhibits the Isc response to mucosal histamine, whereas 100 microM mucosal cimetidine produces no effect. The average initial increases in Isc over time for mucosal vs. serosal histamine addition are significantly different (17.32 +/- 2.8 and 3.76 +/- 0.69 microA/min, respectively). Pretreatment with mucosal amiloride significantly prolongs the effect of mucosal histamine on Isc over a 20-min period from 4.73 +/- 0.33 to 15.48 +/- 3.16 microA. When Cl is replaced by gluconate, mucosal histamine addition results in a gradual decrease in Isc and significantly reduces the effect of mucosal amiloride on Isc from 80.8% to 54.9%. Mucosal histamine inhibits the net transepithelial Na flux by 42% and stimulates the secretion of Cl by 106%. Subsequent addition of serosal bumetanide decreases net Cl secretion by 70% These results suggest that histamine stimulates bumetanide-sensitive Cl secretion and inhibits amiloride-sensitive Na absorption; these effects are mediated by H1 receptors at the apical membrane surface

Mechanisms of sodium and chloride transport across equine tracheal epithelium

1990 ◽  
Vol 259 (6) ◽  
pp. L459-L467 ◽  
Author(s):  
G. J. Tessier ◽  
T. R. Traynor ◽  
M. S. Kannan ◽  
S. M. O3'Grady
Keyword(s):  
Chloride Transport ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Short Circuit Current ◽  
Ringer Solution ◽  
Tracheal Epithelium ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
Cotransport System ◽  
Ethanesulfonic Acid

Equine tracheal epithelium, stripped of serosal muscle, mounted in Ussing chambers, and bathed in plasmalike Ringer solution generates a serosa-positive transepithelial potential of 10–22 mV and a short-circuit current (Isc) of 70–200 microA/cm2. Mucosal amiloride (10 microM) causes a 40–60% decrease in Isc and inhibits the net transepithelial Na flux by 95%. Substitution of Cl with gluconate resulted in a 30% decrease in basal Isc. Bicarbonate substitution with 20 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid decreased the Isc by 21%. The Cl-dependent Isc was inhibited by serosal addition of 1 mM amiloride. Bicarbonate replacement or serosal amiloride (1 mM) inhibits the net Cl flux by 72 and 69%, respectively. Bicarbonate replacement significantly reduces the effects of serosal amiloride (1 mM) on Isc, indicating its effect is HCO3 dependent. Addition of 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP; 100 microM) causes a 40% increase in Isc. This effect is inhibited by subsequent addition of 10 microM serosal bumetanide. Bumetanide (10 microM) reduces net Cl secretion following stimulation with 8-BrcAMP (100 microM). Serosal addition of BaCl2 (1 mM) causes a reduction in Isc equal to that following Cl replacement in the presence or absence of 100 microM cAMP. These results suggest that 1) Na absorption depends on amiloride-inhibitable Na channels in the apical membrane, 2) Cl influx across the basolateral membrane occurs by both a Na-H/Cl-HCO3 parallel exchange mechanism under basal conditions and by a bumetanide-sensitive Na-(K?)-Cl cotransport system under cAMP-stimulated conditions, and 3) basal and cAMP-stimulated Cl secretion depends on Ba-sensitive K channels in the basolateral membrane.

Sodium and chloride transport across the isolated porcine gallbladder

1989 ◽  
Vol 257 (1) ◽  
pp. C45-C51 ◽  
Author(s):  
S. M. O'Grady ◽  
P. J. Wolters
Keyword(s):  
Apical Membrane ◽  
Chloride Transport ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Short Circuit Current ◽  
Ringer Solution ◽  
Disulfonic Acid ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
Conductive Pathway

Porcine gallbladder, stripped of serosal muscle, mounted in Ussing chambers, and bathed in plasma-like Ringer solution generates a serosal positive transepithelial potential of 4-7 mV and a short-circuit current (Isc) of 50-120 microA/cm2. Substitution of Cl with gluconate or HCO3 with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) results in a 50% decrease in Isc. Treatment with 1 mM amiloride (mucosal side) or 0.1 mM acetazolamide (both sides) causes 25-27% inhibition of the Isc. Mucosal addition of 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid inhibits the Isc by 17%. Serosal addition of 0.1 mM bumetanide inhibits the Isc by 28%. Amiloride (1 mM) inhibits the net transepithelial fluxes of Na and Cl by 55 and 41%, respectively. Substitution of Cl with gluconate inhibits the net Na flux by 50%, whereas substitution of HCO3 with HEPES inhibits 85-90% of the net Na flux and changes Cl absorption to net secretion. Based on these results, it is hypothesized that Na and Cl transport across the apical membrane is mediated by two pathways, Na-H/Cl-HCO3 exchange and Na-HCO3 cotransport. Partial recycling of Cl and HCO3 presumably occurs through a Cl conductive pathway and Cl-HCO3 exchange, respectively, in the apical membrane. This results in net Na absorption, which accounts for most of the Isc observed under basal conditions. The effect of bumetanide on the basolateral membrane and the fact that Cl secretion occurs when HCO3 is absent suggests that Cl secretion involves a basolateral NaCl or Na-K-Cl cotransport system arranged in series with a Cl conductive pathway in the apical membrane.

Brain natriuretic peptide stimulates K and Cl secretion across porcine distal colon epithelium

1991 ◽  
Vol 260 (4) ◽  
pp. C750-C755 ◽  
Author(s):  
T. R. Traynor ◽  
S. M. O'Grady
Keyword(s):  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Ringer Solution ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
The Difference ◽  
Distal Colon Epithelium

Porcine distal colon epithelium was mounted in Ussing chambers and bathed with porcine Ringer solution. The serosal addition of brain natriuretic peptide (BNP; 50 nM) or atriopeptin III (AP-III; 500 nM) produced significant increases (50-75 microA/cm2) in short-circuit current (Isc). These increases in Isc were not inhibited by pretreatment with tetrodotoxin (TTX) or 5,8,11,14-eicosatetraynoic acid (ETYA). Analysis of concentration-response relationships revealed that BNP was 5.8-fold more potent than AP-III in stimulating the Isc. BNP and AP-III significantly increased the serosal-to-mucosal (S----M) Cl flux and reduced net Cl absorption by 38 and 41%, respectively. The BNP-stimulated S----M Cl flux was abolished when HCO3 was removed. In contrast, the vasoactive intestinal peptide (VIP)-stimulated S----M Cl flux was not affected by HCO3 replacement. In addition to their effects on Cl transport, BNP and AP-III increased net Rb secretion by 79 and 58%, respectively. BNP-stimulated Rb secretion was reduced by 76% after HCO3 replacement. These results indicate that natriuretic peptides stimulate K- and HCO3-dependent Cl secretion which is not present under basal conditions or after VIP stimulation. The difference in potency between BNP and AP-III suggests that ANP-B receptors may mediate their effects on ion transport in the porcine colon.

Extracellular ATP stimulates K+ secretion across cultured human airway epithelium

1997 ◽  
Vol 272 (6) ◽  
pp. L1084-L1091 ◽  
Author(s):  
L. L. Clarke ◽  
T. Chinet ◽  
R. C. Boucher
Keyword(s):  
Airway Epithelium ◽  
Apical Membrane ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Ringer Solution ◽  
Extracellular Atp ◽  
Cl Secretion ◽  
Human Airway ◽  
Human Airway Epithelium ◽  
K Secretion

Extracellular ATP applied to the luminal side of human airway epithelium (HAE) activates an apical membrane Cl- conductance and transepithelial Cl- secretion. However, in some HAE preparations, we have found that luminal ATP induces a change in short-circuit current (Isc), consistent with K+ secretion. Using intracellular microelectrodes and radioisotopic flux studies, we investigated whether extracellular ATP regulates transepithelial K+ secretion in primary HAE cultures. In physiological Ringer solution, HAE had a negligible electrochemical driving force for Cl- secretion (DFCl), and luminal ATP induced a change in Isc opposite in polarity to Cl- secretion. Intracellular microelectrode measurements indicated that the "reversed" Isc was associated with activation of a hyperpolarizing (K+) conductance in the apical membrane. Radioisotope studies of HAE pretreated with amiloride to induce a favorable DFCl revealed that luminal ATP stimulates a small 42K secretory flux concurrently with Cl- secretion. In ion-substituted Ringer solution, luminal ATP stimulated both the outward (K+) current and the inward (Cl-) current with approximately equal potency (approximately 10(-6) M). We conclude that luminal ATP activates an apical membrane K+ conductance and transepithelial K+ secretion across HAE.

Ba2+ inhibition of VIP- and A23187-stimulated Cl- secretion by T84 cell monolayers

1986 ◽  
Vol 250 (3) ◽  
pp. C486-C494 ◽  
Author(s):  
K. G. Mandel ◽  
J. A. McRoberts ◽  
G. Beuerlein ◽  
E. S. Foster ◽  
K. Dharmsathaphorn
Keyword(s):  
Vasoactive Intestinal Polypeptide ◽  
Apical Membrane ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Short Circuit Current ◽  
Ussing Chambers ◽  
Cell Monolayers ◽  
Cl Secretion ◽  
Cotransport System ◽  
Permeable Supports

Addition of either 10(-8) M vasoactive intestinal polypeptide (VIP) or 10(-6) M A23187 to T84 cell monolayers, grown on permeable supports and mounted in Ussing chambers, stimulated net Cl- secretion. The effect of 10(-6) M A23187 on Cl- flux was consistently smaller than that observed with 10(-8) M VIP. In both cases the increase in net Cl- secretion accounted for the entire change in the observed short-circuit current (Isc). Since Cl- enters the cells through a basolaterally localized Na+-K+-Cl(-)-cotransport system (J. Clin. Invest. 75: 462, 1985), the fate of K+, which is cotransported with Cl- during VIP, and A23187-mediated Cl- secretion was explored. Unidirectional and net transepithelial 42K+ flux rates were negligible compared with 36Cl- flux rates (less than 4% of Cl- flux), indicating that little K+ was secreted along with Cl-. K+ recycling across the basolateral membrane was suggested from experiments in which 86Rb+ efflux (as a tracer for K+) was measured across the apical and basolateral membranes of 86Rb+ -preloaded monolayers under voltage-clamped conditions. In the absence of secretagogues, 86Rb+ efflux was 10-fold higher across the basolateral membrane than across the apical membrane. 86Rb+ efflux across the basolateral membrane was accelerated two- to threefold by addition of either VIP or A23187. In each case accelerated efflux was inhibited by 5 mM Ba2+. Cl- secretion induced by VIP or A23187 was also inhibited by serosal addition of Ba2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanisms of electrolyte transport in rat ileum

1980 ◽  
Vol 238 (3) ◽  
pp. G208-G212
Author(s):  
Y. H. Tai ◽  
R. A. Decker
Keyword(s):  
Transport Mechanism ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Ringer Solution ◽  
Electrolyte Transport ◽  
Secretory Process ◽  
Free Solution ◽  
Rat Ileum ◽  
Ussing Chambers ◽  
Cl Secretion

The short-circuit current (Isc), potential difference (PD), tissue conductance (Gt), and Na and Cl fluxes in the short-circuit state across rat ileum were studied in Ussing chambers using a variety of bathing solutions. In Ringer solution, Isc exceeded net Na absorption and net Cl secretion occurred. Addition of 10 mM glucose increased Isc, PD, Gt, and net Na absorption, which accounts for 70% of the increase in Isc. Removal of HCO3 from Ringer solution did not alter any parameters but increased net Cl secretion due to a decrease in mucosal-to-serosal Cl flux. Reduction by 50% of the [Cl] in HCO3-free solution decreased the net Cl secretion to the level in Ringer solution and increased net Na absorption. Removal of Cl decreased Isc to the value of the net Na absorption and decreased the Na influx across the mucosal membrane by 39%. Isc and PD were near zero and net Cl absorption was observed in a Na-free solution. These results are consistent with the transport mechanism that consists of 1) an electrogenic Na absorptive process that accounts for the Isc, 2) a neutral NaCl-coupled secretory process, and 3) a system by which HCO3- secretion exchanges for Cl- absorption.

Endothelin stimulates chloride secretion across canine tracheal epithelium

1991 ◽  
Vol 261 (2) ◽  
pp. L188-L194 ◽  
Author(s):  
P. I. Plews ◽  
Z. A. Abdel-Malek ◽  
C. A. Doupnik ◽  
G. D. Leikauf
Keyword(s):  
Epithelial Cells ◽  
Short Circuit ◽  
Second Messengers ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Tracheal Epithelium ◽  
Membrane Phospholipids ◽  
Cl Secretion ◽  
Tracheal Epithelial Cells ◽  
Tracheal Epithelial

The endothelins (ET) are a group of isopeptides produced by a number of cells, including canine tracheal epithelial cells. Because these compounds are endogenous peptides that may activate eicosanoid metabolism, we investigated the effects of ET on Cl secretion in canine tracheal epithelium. Endothelin 1 (ET-1) was found to produce a dose-dependent change in short-circuit current (Isc) that increased slowly and reached a maximal value within 10-15 min. When isopeptides of ET were compared, 300 nM ET-1 and ET-2 produced comparable maximal increases in Isc, whereas ET-3 produced smaller changes in Isc (half-maximal concentrations of 2.2, 7.2, and 10.4 nM, respectively). Ionic substitution of Cl with nontransported anions, iodide and gluconate, reduced ET-1-induced changes in Isc. Furthermore, the response was inhibited by the NaCl cotransport inhibitor, furosemide. In paired tissues, ET-1 significantly increased mucosal net 36Cl flux without significant effect on 22Na flux. The increase in Isc induced by ET was diminished by pretreatment with indomethacin. The second messengers mediating the increase in Isc were investigated in cultured canine tracheal epithelial cells. ET-1 stimulated the release of [3H]arachidonate from membrane phospholipids, increased intracellular Ca2+ (occasionally producing oscillations), and increased adenosine 3',5'-cyclic monophosphate accumulation. The latter was diminished by indomethacin. Thus ET is a potent agonist of Cl secretion (with the isopeptides having the following potency: ET-1 greater than or equal to ET-2 greater than ET-3) and acts, in part, through a cyclooxygenase-dependent mechanism.

Gap junctions in rabbit corneal epithelium: limited permeability and inhibition by cAMP

1991 ◽  
Vol 261 (5) ◽  
pp. C857-C864 ◽  
Author(s):  
J. M. Wolosin
Keyword(s):  
Gap Junctions ◽  
Apical Membrane ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Ringer Solution ◽  
Camp Concentration ◽  
Ussing Chambers ◽  
Side Channels ◽  
Short Circuit Currents ◽  
Camp Elevation

Rabbit corneas were mounted in Ussing chambers, and the apical membrane of the superficial cells (SCs) was permeabilized by exposure to digitonin in a Ca(2+)-free Ringer solution. This treatment resulted in the generation of large (60.7 +/- 13.2 microA/cm2, n = 25) Na(+)-dependent tear (T)-to-stroma (S) short-circuit currents (Isc). The Isc was abolished by ouabain and by 1.4 mM Ca2+ and was inhibited by heptanol, 18 alpha-glycyrrhetinic acid, and dieldrin, effects consistent with the notion that corneal transepithelial fluxes include translocations through gap junctions (GJs) before basolateral membrane transport. T-to-S Isc were also generated when T-side Na+ was replaced by K+, eliciting a T-to-S K+ flux via basolateral K+ channels and when, with either Na+ or K+ on the T side, channels were introduced at the apical membrane with amphotericin B. The Isc in all four conditions exhibited similar sensitivity to GJ inhibitors and were inhibited by adenosine 3',5'-cyclic monophosphate (cAMP) elevation. Fluorophotometry combined with SC permeabilization with digitonin demonstrated that the half-time for the SC to sub-SC movement of 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (mol wt 540) exceeded 3 h. These results indicate that junctional communications along the epithelial stratification axis are highly restricted and modulated by cAMP concentration.

Role of CFTR in chloride secretion across human tracheal epithelium

1995 ◽  
Vol 269 (5) ◽  
pp. L561-L566 ◽  
Author(s):  
B. Q. Shen ◽  
R. J. Mrsny ◽  
W. E. Finkbeiner ◽  
J. H. Widdicombe
Keyword(s):  
Apical Membrane ◽  
Short Circuit ◽  
Primary Cultures ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Culture Conditions ◽  
Tracheal Epithelium ◽  
Disulfonic Acid ◽  
Acetoxymethyl Ester ◽  
Cl Channels

We have tested two hypotheses: 1) the cystic fibrosis transmembrane conductance regulator (CFTR) represents the predominant Cl conductance in the apical membrane of human tracheal epithelium, and 2) CFTR in this tissue is close to maximally activated under baseline conditions. In support of the first hypothesis, we found 1) when the level of differentiation of cultures was varied by varying the culture conditions, there was a significant positive correlation between the levels of CFTR and the magnitude of mediator-induced Cl secretion. 2) Amiloride-insensitive baseline short-circuit current (Isc) and mediator-induced increases in Isc were inhibited by diphenylamine-2-carboxylic acid (DPAC) but not by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), a pharmacology consistent with passage of apical membrane Cl current through CFTR; Ca-activated Cl channels are inhibited by DIDS but not by DPAC. 3) Raising temperature from 22 degrees to 37 degrees C increased 125I efflux, and this increase was inhibited by DPAC and blockers of protein kinase A, but not by DIDS or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester. In support of the second hypothesis, we have earlier shown [M. Yamaya, W.E. Finkbeiner, S.Y. Chun, and J.H. Widdicombe. Am. J. Physiol. 262 (Lung Cell. Mol. Physiol. 6): L713-L724, 1992] that adenosine 3',5'-cyclic monophosphate (cAMP)-elevating agents are essentially without effect on Isc across primary cultures of human tracheal epithelium. Here, we further show that these agents are also usually without effect on 125I efflux; the mean increase in efflux in response to elevating cAMP was approximately 20% that of raising temperature from 22 degrees to 37 degrees C.

Prostaglandin-induced recovery of barrier function in porcine ileum is triggered by chloride secretion

1999 ◽  
Vol 276 (1) ◽  
pp. G28-G36 ◽  
Author(s):  
Anthony T. Blikslager ◽  
Malcolm C. Roberts ◽  
Robert A. Argenzio
Keyword(s):  
Short Circuit ◽  
Second Messengers ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Ringer Solution ◽  
Signal Recovery ◽  
Osmotic Gradient ◽  
Current Increase ◽  
Ussing Chambers

We have previously shown that PGI2 and PGE2 have a synergistic role in restoring electrical transepithelial resistance ( R) in ischemia-injured porcine ileum via the second messengers Ca2+ and cAMP. Because Ca2+ and cAMP stimulate Cl− secretion, we assessed the role of PG-induced Cl−secretion in recovery of R. Mucosa from porcine ileum subjected to ischemia for 45 min was mounted in Ussing chambers and bathed in indomethacin and Ringer solution. Addition of PGs stimulated a twofold increase in R, which was preceded by elevations in short-circuit current (increase of 25 μA/cm2). The PG-induced effect on R was partially inhibited with bumetanide, an inhibitor of Cl− secretion. The remaining elevations in R were similar in magnitude to those induced in ischemic tissues by amiloride, an inhibitor of Na+ absorption. Treatment with 10−4 M 8-bromo-cGMP or 300 mosM mucosal urea resulted in elevations in R similar to those attained with PG treatment. PGs signal recovery of Rvia induction of Cl−secretion and inhibition of Na+absorption, possibly by establishing a transmucosal osmotic gradient.

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