Effect of sulfidopeptide leukotrienes D4 and E4 on ileal ion transport in vitro in the rat and rabbit

1988 ◽  
Vol 255 (2) ◽  
pp. G175-G183 ◽  
Author(s):  
P. L. Smith ◽  
D. P. Montzka ◽  
G. P. McCafferty ◽  
M. A. Wasserman ◽  
J. D. Fondacaro
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Bathing Solution ◽  
Na Transport ◽  
Rabbit Ileum ◽  
Rat Ileum ◽  
Ussing Chambers ◽  
Meclofenamic Acid ◽  
Acid Metabolites

Effects of leukotrienes D4 and E4 (LTD4 and LTE4) on electrolyte transport were examined, employing stripped segments of rat and rabbit ileum mounted in Ussing chambers. Addition of LTD4 or LTE4 to the serosal but not the mucosal bathing solution elicited a transient increase in short-circuit current (Isc) with maximal responses seen at 10(-5) M and 10(-8) M in rat and rabbit respectively and a sustained decrease in transepithelial conductance (Gt) in the rat only. In the rat, Cl replacement, reduction of bathing solution [Ca2+] to 1 microM or pretreatment with 1 microM indomethacin or meclofenamic acid inhibited the LTD4- or LTE4-induced Isc changes with no effect on the decrease in Gt. LTD4 (10 microM) transiently increased net Cl secretion and produced a sustained decrease in both unidirectional and net Na transport and mucosal-to-serosal Cl flux in rat ileum. The decrease in unidirectional Na fluxes is accounted for predominantly by a change in the potential independent flux of Na. These results suggest that the increase in Isc in both rat and rabbit is mediated by arachidonic acid metabolites, whereas the decrease in Gt and net Na absorption in rat ileum is mediated by a cyclooxygenase-independent pathway.

In vitro studies of sodium transport across the lower intestine of a desert parrot

1980 ◽  
Vol 239 (3) ◽  
pp. R285-R290
Author(s):  
E. Skadhauge ◽  
T. J. Dawson
Keyword(s):  
Short Circuit ◽  
Electrical Potential ◽  
Flux Ratio ◽  
Short Circuit Current ◽  
Electrical Potential Difference ◽  
Na Transport ◽  
Salt Loading ◽  
Ussing Chambers ◽  
Lower Intestine

The lower intestine (coprodeum and colon) of the Australian parrot, the galah, was mounted in Ussing chambers. Short-circuit current (SCC), electrical potential difference (PD), and unidirectional fluxes of Na and Cl were measured in birds that were fed mixed seeds or were NaCl loaded. The net Na transport of both coprodeum and colon was nearly equal to the SCC, and the flux ratio for Cl was unity. In birds which received mixed seeds, average coprodeal Na transport was 7.8 mu eq . cm-2 . h-1, and PD was 19 mV. The Km for Na was 5.7 meq/l. In colon, Na transport was reduced by 67% and PD by 70%. The ratio between unidirectional Na and Cl fluxes in the serosa-mucosa direction was 0.7. Salt loading suppressed coprodeal, but increased colonic Na transport. The coprodeal and colonic SCC and NA transport of birds receiving mixed seeds were inhibited by amiloride on the mucosal side. Colonic SCC of NaCl-loaded birds was only slightly reduced by amiloride (by 17%), but stimulated by amino acids (by 18%).

Bicarbonate secretion by rabbit proximal colon

1986 ◽  
Vol 251 (4) ◽  
pp. G436-G445 ◽  
Author(s):  
S. K. Sullivan ◽  
P. L. Smith
Keyword(s):  
Transport Process ◽  
Short Circuit ◽  
Proximal Colon ◽  
Bathing Solution ◽  
Bicarbonate Secretion ◽  
Rabbit Ileum ◽  
Ussing Chambers ◽  
Ph Stat ◽  
Dependent Mechanism

Stripped segments of proximal colon (1-6 cm distal to the ampulla caecalis coli) were studied in vitro in Ussing chambers under short-circuit conditions using the pH-stat technique. With glucose and HCO3-CO2 present in the serosal bathing solution only, proximal colon alkalinizes the luminal bathing solution at a rate of 2.1 +/- 0.2 mu eq X h-1 X cm-2 (n = 36). With HCO3-CO2 present in the luminal bathing solution alone, proximal colon does not significantly acidify or alkalinize the serosal bathing solution. Addition of glucose (10 mM) to the luminal bathing solution abolished luminal alkalinization. Removal of HCO3 and CO2 from the serosal bathing solution or replacement of O2 with N2 also abolished luminal alkalinization. Acetazolamide (0.1 mM) added to both bathing solutions did not alter the rate of luminal alkalinization. Ion-replacement studies revealed that the alkalinization process was highly dependent on the presence of Na in the bathing solutions and much less dependent on the presence of Cl. Furthermore, ouabain (0.1 mM) significantly reduced luminal alkalinization. As in rabbit ileum, serosal epinephrine (0.1 mM) did not alter luminal alkalinization but increased serosal alkalinization by a Na-dependent mechanism. These results suggest that luminal alkalinization results from a Na-dependent, active transcellular HCO3 transport process and that a Na-dependent HCO3 absorptive process is activated by adrenergic stimuli.

Sodium dependence of luminal alkalinization by rabbit ileal mucosa

1985 ◽  
Vol 249 (3) ◽  
pp. G358-G368 ◽  
Author(s):  
P. L. Smith ◽  
M. A. Cascairo ◽  
S. K. Sullivan
Keyword(s):  
Prostaglandin E1 ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Bathing Solution ◽  
Ileal Mucosa ◽  
Adrenergic Agents ◽  
Ussing Chambers ◽  
Sodium Removal ◽  
Ph Stat

Stripped rabbit ileal mucosa was studied in vitro in Ussing chambers under short-circuit conditions using the pH-stat technique to determine basal rates of luminal alkalinization; the contribution of the shunt pathway to the alkalinization process; the effects of Na, Cl, or HCO3 removal from the bathing solutions on luminal alkalinization; and the effects of epinephrine, ouabain, 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS), acetazolamide, prostaglandin E1 (PGE1), A23187, sugars, or amino acids on the alkalinization process. Results from these studies reveal that, under basal conditions, the rate of luminal alkalinization accounts for 81% of the basal short-circuit current (Isc), although there was no correlation between the rate of alkalinization and Isc. The contribution of the shunt to the alkalinization process accounts for less than 10% of the mucosal-to-serosal HCO3 flux. Removal of Cl from the bathing solutions increased the rate of luminal alkalinization and decreased Isc. Sodium removal from the bathing solutions reduced both Isc and the rate of luminal alkalinization. Addition of DIDS to the luminal or serosal bathing solution reduced luminal alkalinization less than 30%. Acetazolamide, PGE1, and A23187 were all without effect on luminal alkalinization. Addition of 3-O-methyl-D-glucose or L-alanine to the luminal bathing solution did not alter luminal alkalinization but increased Isc, D-Glucose added to the luminal bathing solution reduced luminal alkalinization. This effect appears to result from metabolic acid production since 1) it is not seen with L-alanine or 3-O-methyl-D-glucose; 2) in the absence of HCO3 in the bathing solutions, D-glucose increased luminal acidification; and 3) luminal addition of fructose also reduced the rate of luminal alkalinization. Addition of epinephrine to the serosal bathing solution stimulates a Na-dependent serosal alkalinization process. These results suggest that luminal alkalinization results from Na-dependent, transcellular HCO3 transport and that a Na-dependent, HCO3 absorptive process is stimulated by adrenergic agents.

Colonic potassium and chloride secretion: role of cAMP and calcium

1985 ◽  
Vol 248 (1) ◽  
pp. G103-G109 ◽  
Author(s):  
R. D. McCabe ◽  
P. L. Smith
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Bathing Solution ◽  
Ionophore A23187 ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
Intracellular Ca

Stripped rabbit colonic mucosa was studied in vitro in Ussing chambers to further investigate the role of Ca in regulating K and Cl secretion stimulated by the divalent cation ionophore A23187, prostaglandin E1 (PGE1), or 8-bromo-cAMP (8BrcAMP). To assess the effects of these secretagogues on the paracellular shunt permeability, we measured the Na concentration dependence of the serosal-to-mucosal Na flux in the absence or presence of these stimuli. Results from these studies reveal that changes in net K and Cl secretion produced by secretory stimuli cannot be accounted for by a change in shunt permeability. The possible involvement of Ca in the secretory response of the colon to these stimuli was investigated by measuring the changes in Cl and K transport elicited by A23187, PGE1, or 8BrcAMP in the absence or presence of trifluoperazine (10(-4) M) added to the serosal bathing solution. Trifluoperazine alone did not significantly alter basal Na or Cl fluxes or short-circuit current (Isc) but did decrease transepithelial conductance (Gt) and the serosal-to-mucosal K flux. Pretreatment of the tissues with trifluoperazine significantly reduced or abolished the changes in K fluxes elicited by A23187, 8BrcAMP, or PGE1 without altering the changes in Cl transport, Isc, and Gt. These results suggest that K secretion induced by these secretagogues involves an increase in intracellular Ca concentration and may be mediated by calmodulin.

Vibrio choleraeACE stimulates Ca2+-dependent Cl−/HCO3−secretion in T84 cells in vitro

2000 ◽  
Vol 279 (3) ◽  
pp. C567-C577 ◽  
Author(s):  
Michele Trucksis ◽  
Timothy L. Conn ◽  
Steven S. Wasserman ◽  
Cynthia L. Sears
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Fluid Secretion ◽  
Apical Surface ◽  
Rabbit Ileum ◽  
T84 Cells ◽  
Ussing Chambers ◽  
Intracellular Ca ◽  
Vitro Model

ACE, accessory cholera enterotoxin, the third enterotoxin in Vibrio cholerae, has been reported to increase short-circuit current ( Isc) in rabbit ileum and to cause fluid secretion in ligated rabbit ileal loops. We studied the ACE-induced change in Iscand potential difference (PD) in T84 monolayers mounted in modified Ussing chambers, an in vitro model of a Cl−secretory cell. ACE added to the apical surface alone stimulated a rapid increase in Iscand PD that was concentration dependent and immediately reversed when the toxin was removed. Ion replacement studies established that the current was dependent on Cl−and HCO3−. ACE acted synergistically with the Ca2+-dependent acetylcholine analog, carbachol, to stimulate secretion in T84 monolayers. In contrast, the secretory response to cAMP or cGMP agonists was not enhanced by ACE. The ACE-stimulated secretion was dependent on extracellular and intracellular Ca2+but was not associated with an increase in intracellular cyclic nucleotides. We conclude that the mechanism of secretion by ACE involves Ca2+as a second messenger and that this toxin stimulates a novel Ca2+-dependent synergy.

scholarly journals Ion Transport in Isolated Rabbit Ileum

1964 ◽  
Vol 47 (6) ◽  
pp. 1043-1059 ◽  
Author(s):  
Stanley G. Schultz ◽  
Ralph Zalusky
Keyword(s):  
Short Circuit ◽  
Sugar Transport ◽  
Short Circuit Current ◽  
Metabolic Fate ◽  
Na Transport ◽  
Perfusion Medium ◽  
Rabbit Ileum ◽  
Low Concentrations ◽  
Solution Bathing

The addition of actively transported sugars to the solution bathing the mucosal surface of an in vitro preparation of distal rabbit ileum results in a rapid increase in the transmural potential difference, the short-circuit current, and the rate of active Na transport from mucosa to serosa. These effects are dependent upon the active transport of the sugar per se and are independent of the metabolic fate of the transported sugar. Furthermore, they are inhibited both by low concentrations of phlorizin in the mucosal solution and by low concentrations of ouabain in the serosal solution. The increase in the short-circuit current, ΔIsc, requires the presence of Na in the perfusion medium and its magnitude is a linear function of the Na concentration. On the other hand, ΔIsc is a saturable function of the mucosal sugar concentration which is consistent with Michaelis-Menten kinetics suggesting that the increase in active Na transport is stoichiometrically related to the rate of active sugar transport. An interpretation of these findings in terms of a hypothetical model for intestinal Na and sugar transport is presented.

Concentration-dependent effects of disulfonic stilbenes on colonic chloride transport

1986 ◽  
Vol 250 (1) ◽  
pp. G44-G49 ◽  
Author(s):  
P. L. Smith ◽  
S. K. Sullivan ◽  
R. D. McCabe
Keyword(s):  
Colonic Mucosa ◽  
Chloride Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Bathing Solution ◽  
Ussing Chambers ◽  
Unidirectional Fluxes ◽  
Dose Dependent ◽  
Disulfonic Stilbenes

Stripped rabbit colonic mucosa was studied in vitro in Ussing chambers to determine effects of the disulfonic stilbenes 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonate (SITS) and 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) and the diuretic furosemide on unidirectional and net Cl fluxes. Results from these studies reveal that SITS (1 mM) added to either the serosal or mucosal bathing solution reduced both unidirectional Cl fluxes with no significant change in net Cl flux. The effects of SITS do not appear to be mediated by an effect on the shunt permeability since SITS (1 mM) did not alter either the intercept or slope of the Na concentration dependence of the serosal-to-mucosal Na flux. Furosemide (1 mM) decreased the serosal-to-mucosal Cl flux without altering short-circuit current (Isc) when added to the luminal bathing solution and reduced both unidirectional fluxes and increased Isc when added to the serosal bathing solution. DIDS (0.5 mM) added to the luminal bathing solution did not alter unidirectional Cl fluxes or Isc. However, serosal addition of DIDS produced dose-dependent changes in Cl transport. At 5 microM DIDS reduced the mucosal-to-serosal Cl flux without altering the serosal-to-mucosal flux or Isc. At 50 microM DIDS reduced the mucosal-to-serosal Cl flux and increased Isc, and at 0.5 mM DIDS increased the serosal-to-mucosal Cl flux, reduced the mucosal-to-serosal Cl flux, and increased Isc and transepithelial conductance. The effect of 0.5 mM DIDS on Isc was reduced by Ca removal from the serosal bathing solution and by the loop diuretics furosemide and bumetanide.(ABSTRACT TRUNCATED AT 250 WORDS)

Endogenous norepinephrine release induced by tyramine modulates intestinal ion transport

1981 ◽  
Vol 241 (3) ◽  
pp. G264-G269 ◽  
Author(s):  
E. J. Tapper ◽  
A. S. Bloom ◽  
D. L. Lewand
Keyword(s):  
Ion Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Current Response ◽  
Na Transport ◽  
Rabbit Ileum ◽  
Nacl Transport ◽  
6 Hydroxydopamine ◽  
Intestinal Ion Transport

To study the effects of endogenous norepinephrine on intestinal ion transport, we tested the actions of an indirect sympathomimetic agent, tyramine, on electrolyte fluxes in the short-circuited rabbit ileum in vitro. Tyramine (10(-5) M) alone had no effect on short-circuit current or Na transport but increased Cl absorption. Tyramine decreased the short-circuit current, stimulated both Na and Cl absorption, and increased tissue conductance when its breakdown by endogenous monoamine oxidase enzymes was inhibited by pretreatment with pargyline (10(-4) M). Pargyline alone had no effect on short-circuit current and NaCl transport. The effect of norepinephrine on NaCl transport was inhibited by the alpha-adrenergic receptor antagonist, phentolamine (10(-7) M). This response was also prevented when animals were chemically sympathectomized with 6-hydroxydopamine. Although sympathectomy decreased measurable tissue norepinephrine by 80%, it did not alter basal short-circuit current, Na and Cl absorption, and the short-circuit current response to glucose-stimulated Na transport and to exogenous norepinephrine. Thus, a pool of norepinephrine in intestinal adrenergic neurons released by tyramine affects intestinal ion transport but does not alter basal ion transport. These data suggest close neuropharmacologic similarities between the adrenergic nervous system in the intestine and other organs.

Aldosterone modulates electrogenic Cl secretion in the colon of the hen (Gallus domesticus)

1991 ◽  
Vol 261 (6) ◽  
pp. R1533-R1541 ◽  
Author(s):  
W. Clauss ◽  
V. Dantzer ◽  
E. Skadhauge
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Na Channel ◽  
Na Transport ◽  
Electrogenic Transport ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
Cotransport System ◽  
Hormonal Stimulus

The regulation of Na and Cl transport in hen colon by mineralocorticoids was investigated with isolated epithelia in vitro by histological and electrophysiological techniques. The electrogenic transport of Na and Cl was measured in Ussing chambers by the short-circuit current technique and was identified by the specific inhibitors amiloride and bumetanide or by the secretagogue theophylline. Hens were maintained either on low (LS)- or on high-NaCl diets (HS), and the plasma aldosterone (PA) levels of these groups were measured with radioimmunoassay. A group of HS hens received injections of aldosterone at a 6-h schedule before experiments. A group of LS hens was resalinated, and experiments were carried out at a 24-h interval for up to 3 days after resalination. The LS diet stimulated PA levels ninefold, compared with HS hens. Na transport was modulated by the hormonal stimulus in a way that the apical Na entry switched from an electrogenic Na-amino acid-hexose cotransport system completely to an amiloride-sensitive Na channel. Electrogenic Cl secretion was induced by theophylline and was inhibited by bumetanide. NaCl deprivation, resalination or aldosterone injection modulated electrogenic Cl secretion in parallel between 7 (HS) and 14.4 mu eq.cm-2.h-1 (LS), with pronounced alteration in tissue conductance. These findings reveal a new action of aldosterone that, besides stimulating Na absorption, also directly or indirectly modulates Cl secretion.

Protein kinase C potentiates cAMP-stimulated mouse duodenal mucosal bicarbonate secretion in vitro

2004 ◽  
Vol 286 (5) ◽  
pp. G814-G821 ◽  
Author(s):  
Bi-Guang Tuo ◽  
Jimmy Y. C. Chow ◽  
Kim E. Barrett ◽  
Jon I. Isenberg
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Duodenal Mucosa ◽  
Bicarbonate Secretion ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ussing Chambers ◽  
Duodenal Bicarbonate Secretion

PKC has been shown to regulate epithelial Cl- secretion in a variety of models. However, the role of PKC in duodenal mucosal bicarbonate secretion is less clear. We aimed to investigate the role of PKC in regulation of duodenal mucosal bicarbonate secretion. Bicarbonate secretion by murine duodenal mucosa was examined in vitro in Ussing chambers using a pH-stat technique. PKC isoform expression and activity were assessed by Western blotting and in vitro kinase assays, respectively. PMA (an activator of PKC) alone had no effect on duodenal bicarbonate secretion or short-circuit current ( Isc). When PMA and dibutyryl-cAMP (db-cAMP) were added simultaneously, PMA failed to alter db-cAMP-stimulated duodenal bicarbonate secretion or Isc ( P > 0.05). However, a 1-h preincubation with PMA potentiated db-cAMP-stimulated duodenal bicarbonate secretion and Isc in a concentration-dependent manner (from 10-8 to 10-5M) ( P < 0.05). PMA preincubation had no effects on carbachol- or heat-stable toxin-stimulated bicarbonate secretion. Western blot analysis revealed that PKCα, -γ, -ϵ, -θ, -μ, and -ι/λ were expressed in murine duodenal mucosa. Ro 31–8220 (an inhibitor active against PKCϵ, -α, -β, and -γ), but not Gö 6983 (an inhibitor active against PKCα, -γ, -β, and -δ), reversed the potentiating effect of PMA on db-cAMP-stimulated bicarbonate secretion. PMA also time- and concentration-dependently increased the activity of PKCϵ, an effect that was prevented by Ro 31–8220 but not Gö 6983. These results demonstrate that activation of PKC potentiates cAMP-stimulated duodenal bicarbonate secretion, whereas it does not modify basal secretion. The effect of PKC on cAMP-stimulated bicarbonate secretion is mediated by the PKCϵ isoform.

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