The effect of [Arg8]vasopressin on electrogenic chloride secretion in cultured rat epididymal epithelia

1994 ◽  
Vol 267 (2) ◽  
pp. C607-C616 ◽  
Author(s):  
K. B. Lai ◽  
W. O. Fu ◽  
W. H. Ko ◽  
H. C. Chan ◽  
P. Y. Wong
Keyword(s):  
Regional Differences ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Induced Response ◽  
Efferent Duct ◽  
Ussing Chambers ◽  
Cauda Epididymidis ◽  
Dose Dependent Increase ◽  
Dose Dependent

Primary cultured rat efferent ductal epithelia and cauda epididymal epithelial were mounted in Ussing chambers to study the effect of arginine vasopressin (AVP) on chloride secretion in the male excurrent duct. The regional differences in the signal transduction pathways involved were also investigated. In both the efferent duct and the cauda epididymidis, basolateral addition of AVP resulted in a dose-dependent increase in the short-circuit current (Isc), which was mediated via V1 receptor. Replacement of ambient Cl- with gluconate or pretreatment of a Cl- channel blocker, diphenylamine-2-carboxylate (apical, 1 mM), completely abolished the response, whereas addition of amiloride had no effect on the Isc. Pretreating the epithelia of the efferent duct with indomethacin (apical, 5 microM) or forskolin (basolateral, 1 microM), but not thapsigargin (apical, 1 microM) or trifluoperazine (apical, 20 microM), significantly inhibited the AVP response (P < 0.001). By comparison, pretreating the epithelia of the cauda epididymidis with any of the four agents significantly reduced the AVP-evoked response. These results suggested that the stimulation of chloride secretion by AVP in the efferent duct and the cauda epididymidis is mediated by prostaglandin synthesis and involves adenosine 3',5'-cyclic monophosphate (cAMP) as a second messenger. In the cauda epididymidis, calcium, in addition to cAMP, may play a role in mediating the AVP-induced response.

Effects of the inflammatory mediator prostaglandin D2 on submucosal neurons and secretion in guinea pig colon

1994 ◽  
Vol 266 (1) ◽  
pp. G132-G139 ◽  
Author(s):  
T. Frieling ◽  
C. Rupprecht ◽  
A. B. Kroese ◽  
M. Schemann
Keyword(s):  
Guinea Pig ◽  
Ganglion Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Prostaglandin D2 ◽  
Flux Chamber ◽  
Dose Dependent Increase ◽  
Dose Dependent

Conventional flux chamber and intracellular recording methods were used to investigate the mode of action of prostaglandin D2 (PGD2) on ion transport in muscle-stripped segments of guinea pig colon and on colonic submucosal ganglion cells. Application of PGD2 resulted in a dose-dependent increase in short-circuit current that was reduced by serosal addition of bumetanide, tetrodotoxin, atropine, or piroxicam, but not hexamethonium. Application of PGD2 to submucosal neurons evoked a depolarization of the membrane potential that was associated with an enhanced spike discharge. In AH/type 2 neurons, postspike afterhyperpolarizations were reduced in amplitude and duration. The depolarizing responses to PGD2 were not affected by tetrodotoxin, indicative of a direct effect of PGD2 on the impaled neurons. Whereas fast excitatory postsynaptic potentials (EPSPs) were not affected by PGD2, slow EPSPs were reduced by a presynaptic effect, indicating presynaptic suppression of noncholinergic neurotransmitter release. The study demonstrates that PGD2 acts as a neuromodulator to evoke nerve-mediated chloride secretion, predominantly through activation of cholinergic submucosal neurons. The results further indicate that PGD2 released from lamina propria immune cells during antigenic stimulation may influence mucosal function by altering electrical behavior of submucosal neurons.

Nongenomic effect of testosterone on chloride secretion in cultured rat efferent duct epithelia

2001 ◽  
Vol 280 (5) ◽  
pp. C1160-C1167 ◽  
Author(s):  
G. P. H. Leung ◽  
S. B. Cheng-Chew ◽  
P. Y. D. Wong
Keyword(s):  
Fluid Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Bathing Solution ◽  
Protein Synthesis Inhibitors ◽  
Efferent Duct ◽  
Nongenomic Action ◽  
Dose Dependent

Short-circuit current ( I sc) technique was used to investigate the role of testosterone in the regulation of chloride secretion in cultured rat efferent duct epithelia. Among the steroids tested, only testosterone, and to a lesser extent, 5α-dihydrotestosterone (5α-DHT), reduced the basal and forskolin-induced I sc in cultured rat efferent duct epithelia when added to the apical bathing solution. Indomethacin, a 3α-hydroxysteroid dehydrogenase, did not affect the inhibitory effect of 5α-DHT. The effect of testosterone occurred within 10–20 s upon application and was dose dependent with apparent IC50 value of 1 μM. The effect was abolished by removal of Cl− but not HCO[Formula: see text] from the normal Krebs-Henseleit solution, suggesting that testosterone mainly inhibited Cl− secretion. The efferent duct was found to be most sensitive to testosterone, while the caput and the cauda epididymidis were only mildly sensitive. Cyproterone acetate, a steroidal antiandrogen, or flutamide, a nonsteroidal antiandrogen, did not block the effect of testosterone on the forskolin-induced I sc, nor did protein synthesis inhibitors, cycloheximide, or actinomycin D. However, pertussis toxin, a Gi protein inhibitor, attenuated the inhibition of forskolin-induced I sc by testosterone. Testosterone caused a dose-dependent inhibition of forskolin-induced rise in cAMP in efferent duct cells. It is suggested that the rapid effect of testosterone was mediated through a membrane receptor that is negatively coupled to adenylate cyclase via Gi protein. The role of nongenomic action of testosterone in the regulation of electrolyte and fluid transport in the efferent duct is discussed.

Regional differences in the response to platelet-activating factor in rabbit colon

1992 ◽  
Vol 82 (6) ◽  
pp. 673-680 ◽  
Author(s):  
S. P. L. Travis ◽  
D. P. Jewell
Keyword(s):  
Ion Transport ◽  
Regional Differences ◽  
Chloride Transport ◽  
Short Circuit ◽  
Platelet Activating Factor ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Anion Secretion ◽  
Ussing Chambers

1. Platelet-activating factor is an inflammatory mediator related to eicosanoids which is known to stimulate anion secretion in the distal colon. Since there are regional differences in ion transport within the colon, the influence of platelet-activating factors on ion transport and epithelial permeability has been studied in rabbit caecum and distal colon mounted in Ussing chambers. 2. The effect of platelet-activating factor (1–50 nmol/l) on net electrogenic ion transport was to stimulate a biphasic increase in short-circuit current in the distal colon but not in the caecum. The platelet-activating factor-induced rise in short-circuit current was shown by ion replacement and pharmacological inhibitor studies to be consistent with chloride and bicarbonate secretion in the early phase, but with chloride secretion alone in the later phase. The effect on ion transport was specific and reversible and was enhanced by 0.25% BSA. 3. Colonic permeability, assessed by transmucosal resistance and mannitol flux, was increased by platelet-activating factor in both the distal colon and the caecum. This was consistent with an effect on platelet-activating factor on the paracellular pathway, because resistance decreased even when transcellular chloride transport was inhibited by frusemide or ion replacement. A specific platelet-activating factor antagonist (U66985) inhibited the effects of platelet-activating factor in both the distal colon and the caecum. 4. The results show that platelet-activating factor stimulates anion secretion only in the distal colon, but increases permeability in both the caecum and the distal colon.

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.

Ion transport characteristics of the murine trachea and caecum

1992 ◽  
Vol 82 (6) ◽  
pp. 667-672 ◽  
Author(s):  
S. N. Smith ◽  
E. W. F. W. Alton ◽  
D. M. Geddes
Keyword(s):  
Cystic Fibrosis ◽  
Ion Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Open Circuit ◽  
Potential Difference ◽  
Cystic Fibrosis Gene ◽  
Tissue Type ◽  
Ussing Chambers

1. The basic defect in cystic fibrosis relates to abnormalities of ion transport in affected tissues, such as the respiratory and gastrointestinal tracts. The identification of the cystic fibrosis gene has enabled studies on the production of a cystic fibrosis transgenic mouse to be undertaken. Knowledge of normal ion transport will be necessary for the validation of any such animal model. We have therefore characterized selected responses of the murine trachea and caecum mounted in ‘mini’ Ussing chambers under open-circuit conditions. 2. Basal values for the trachea were: potential difference, 1.1 mV (sem 0.2; n=18); equivalent short-circuit current, 20.4 μA/cm2 (3.6); conductance, 18.2 mS/cm2 (1.7). Corresponding values for the caecum were: potential difference, 0.7 mV (0.1; n=18); equivalent short-circuit current, 11.0 μA/cm2 (1.6); conductance, 14.5 mS/cm2 (1.4). 3. Amiloride (10 μmol/l) produced a significant (P < 0.001) fall in potential difference of 43.0% (5.7) in the trachea, but had no significant effect in the caecum. 4. Subsequently, one of three protocols was used to assess the capacity of either tissue for chloride secretion. Addition of a combination of forskolin (1 μmol/l) and zardaverine (10 μmol/l) produced rises in the potential difference of 873% (509) in the trachea and 399% (202) in the caecum. Both A23187 (10 μmol/l) and phorbol dibutyrate (10 nmol/l) increased tracheal potential difference by 350% (182) and 147% (47), respectively. Neither had a significant effect in the caecum. 5. Subsequent addition of bumetanide caused a fall in the stimulated potential difference of between 39.8% and 71.7%, depending on secretagogue and tissue type. 6. When a homozygous transgenic cystic fibrosis mouse becomes available, these responses should allow such an animal to be distinguished from normal or heterozygous mice.

Expression of the chloride channel ClC-2 in the murine small intestine epithelium

2000 ◽  
Vol 279 (6) ◽  
pp. C1787-C1794 ◽  
Author(s):  
Katalin Gyömörey ◽  
Herman Yeger ◽  
Cameron Ackerley ◽  
Elizabeth Garami ◽  
Christine E. Bear
Keyword(s):  
Small Intestine ◽  
Chloride Channel ◽  
Chloride Transport ◽  
Short Circuit ◽  
Chloride Ion ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Ussing Chambers ◽  
Dependent Change ◽  
Knockout Animals

The chloride channel ClC-2 has been implicated in neonatal airway chloride secretion. To assess its role in secretion by the small intestine, we assessed its subcellular expression in ileal segments obtained from mice and studied the chloride transport properties of this tissue. Chloride secretion across the mucosa of murine ileal segments was assessed in Ussing chambers as negative short-circuit current ( Isc). If ClC-2 contributed to chloride secretion, we predicted on the basis of previous studies that negative Iscwould be stimulated by dilution of the mucosal bath and that this response would depend on chloride ion and would be blocked by the chloride channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid but not by DIDS. In fact, mucosal hypotonicity did stimulate a chloride-dependent change in Iscthat exhibited pharmacological properties consistent with those of ClC-2. This secretory response is unlikely to be mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) channel because it was also observed in CFTR knockout animals. Assessment of the native expression pattern of ClC-2 protein in the murine intestinal epithelium by confocal and electron microscopy showed that ClC-2 exhibits a novel distribution, a distribution pattern somewhat unexpected for a channel involved in chloride secretion. Immunolabeled ClC-2 was detected predominantly at the tight junction complex between adjacent intestinal epithelial cells.

Effect of sorbin on electrolyte transport in rat and human intestine

1999 ◽  
Vol 276 (1) ◽  
pp. G107-G114 ◽  
Author(s):  
Bruno Eto ◽  
Michel Boisset ◽  
Bertrand Griesmar ◽  
Jehan-François Desjeux
Keyword(s):  
Water Absorption ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Electrolyte Transport ◽  
Secretory Diarrhea ◽  
Maximal Effect ◽  
Human Intestine ◽  
Ussing Chambers ◽  
Antisecretory Effect ◽  
Dose Dependent

Stimulating water absorption in the colon represents an important target to reduce stool output in secretory diarrhea. Recently, a 153-amino-acid peptide was isolated from porcine upper small intestine and purified, taking into account the increase of water absorption in guinea pig gallbladder. Accordingly, this peptide was named sorbin. The aim of the present study was to determine if the COOH-terminal heptapeptide of sorbin (C7-sorbin) participates in the regulation of electrolyte transport in the colon. Different regions (from duodenum to colon) of stripped intestinal mucosa from rats or humans were mounted in Ussing chambers to measure the changes in short-circuit current (Δ Isc) and net22Na and36Cl fluxes ([Formula: see text] and[Formula: see text]) after serosal exposure of 10−7to 10−3M C7-sorbin. In fasted rat intestine, C7-sorbin (10−4M) induced an immediate reduction in Iscin the distal ileum and proximal and distal colon but not in the duodenum and jejunum. In the colon, Iscreduction and[Formula: see text] and[Formula: see text] stimulation were dose dependent (EC50= 2 × 10−5M). At 10−3M, maximal effect was observed (Δ Isc= −1.14 ± 0.05, Δ[Formula: see text] = +4.97 ± 1.38, and Δ[Formula: see text] = +9.25 ± 1.44 μeq ⋅ h−1⋅ cm−2). C7-sorbin (10−3M) inhibited the increase in Iscinduced by a series of 10 secretory agents such as secretin, vasoactive intestinal peptide, PGE2, and serotonin. In HT-29-Cl19A cells, C7-sorbin induced an increase in Isc, with a maximal effect at 10−3M (Δ Isc= 0.29 ± 0.10 μeq ⋅ h−1⋅ cm−2). In human intestine, a dose-dependent decrease in Iscwas observed in right and sigmoid colons in basal and stimulated conditions (EC50≅ 10−5M; at 10−4M, Δ Isc= −2.66 ± 0.17 μeq ⋅ h−1⋅ cm−2) but not in the jejunum. The results indicate that C7-sorbin stimulated NaCl neutral absorption and inhibited electrogenic Cl−in rat and human intestinal epithelia. In addition, the antisecretory effect was essentially observed in the distal part of both rat and human intestine and the magnitude of the proabsorptive effect was directly related to the magnitude of the previously induced secretion.

Stroking human jejunal mucosa induces 5-HT release and Cl− secretion via afferent neurons and 5-HT4receptors

1999 ◽  
Vol 277 (3) ◽  
pp. G515-G520 ◽  
Author(s):  
John M. Kellum ◽  
Francisco C. Albuquerque ◽  
Michael C. Stoner ◽  
R. Paul Harris
Keyword(s):  
Receptor Antagonist ◽  
Sensory Neurons ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Jejunal Mucosa ◽  
Afferent Neurons ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
Reflex Pathways

5-Hydroxytryptamine (5-HT) release and neural reflex pathways activated in response to mucosal stroking were investigated in muscle-stripped human jejunum mounted in modified Ussing chambers. The mucosa was stroked with a brush at 1/s for 1–10 s. Mucosal stroking resulted in a significant increase in the concentration of 5-HT in the mucosal bath within 5 min. It also was associated with a reproducible positive change (Δ) in short-circuit current ( I sc), which was abolished by inhibitors of chloride secretion. Capsaicin and hexamethonium significantly inhibited the Δ I sc but not the release of 5-HT. The Δ I sc was inhibited by TTX but not by atropine. It was also inhibited by the 5-HT3,4 receptor antagonist tropisetron (10 μM) and the 5-HT4,3 receptor antagonist SDZ-205-557 (10 μM) but not by preferential antagonists of 5-HT1P, 5-HT2A, or 5-HT3 receptors. These results suggest that mucosal stroking induces release of mucosal 5-HT, which activates a 5-HT4 receptor on enteric sensory neurons, evoking a neuronal reflex that stimulates chloride secretion.

Stimulation of chloride secretion by baicalein in isolated rat distal colon

2002 ◽  
Vol 282 (3) ◽  
pp. G508-G518 ◽  
Author(s):  
W. H. Ko ◽  
V. W. Y. Law ◽  
W. C. Y. Yip ◽  
G. G. L. Yue ◽  
C. W. Lau ◽  
...  
Keyword(s):  
Colonic Mucosa ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Distal Colon ◽  
Chloride Secretion ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Ussing Chambers ◽  
Rat Distal Colon ◽  
Cystic Fibrosis Transmembrane

The effect of baicalein on mucosal ion transport in the rat distal colon was investigated in Ussing chambers. Mucosal addition of baicalein (1–100 μM) elicited a concentration-dependent short-circuit current ( I sc) response. The increase in I sc was mainly due to Cl−secretion. The presence of mucosal indomethacin (10 μM) significantly reduced both the basal and subsequent baicalein-evoked I sc responses. The baicalein-induced I sc were inhibited by mucosal application of diphenylamine-2-carboxylic acid (100 μM) and glibenclamide (500 μM) and basolateral application of chromanol 293B (30 μM), a blocker of KvLQT1 channels and Ba2+ ions (5 mM). Treatment of the colonic mucosa with baicalein elicited a threefold increase in cAMP production. Pretreating the colonic mucosa with carbachol (100 μM, serosal) but not thapsigargin (1 μM, both sides) abolished the baicalein-induced I sc. Addition of baicalein subsequent to forskolin induced a further increase in I sc. These results indicate that the baicalein evoked Cl− secretion across rat colonic mucosa, possibly via a cAMP-dependent pathway. However, the action of baicalein cannot be solely explained by its cAMP-elevating effect. Baicalein may stimulate Cl− secretion via a cAMP-independent pathway or have a direct effect on cystic fibrosis transmembrane conductance regulator.

Effect of atriopeptin II on isolated opercular epithelium of Fundulus heteroclitus

1988 ◽  
Vol 254 (1) ◽  
pp. R27-R32 ◽  
Author(s):  
J. I. Scheide ◽  
J. A. Zadunaisky
Keyword(s):  
Fundulus Heteroclitus ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Chloride Secretion ◽  
Chloride Cells ◽  
Induced Response ◽  
Ion Regulation ◽  
Cyclic Monophosphate ◽  
Stimulation Of

The effect of atriopeptin II (ANF) on the in vitro opercular epithelium was investigated by use of short-circuit current techniques. Serosal addition of ANF stimulates chloride secretion (short-circuit current) 19% above control values with a 7% increase in tissue conductance. Mucosal addition of ANF to the opercular epithelium was without effect. The ANF stimulation of the current was dose dependent with a maximum at 10(-7) M. The addition of ANF had no effect on the current or the conductance of opercular epithelia bathed in Cl--free Ringer. The opercular current could be stimulated above the ANF response by isoproterenol (10(-6) M). Pretreatment of the opercular epithelium with propranolol (10(-5) M) did not inhibit the stimulation of the short-circuit current by ANF but did inhibit the isoproterenol response indicating that the ANF stimulatory activity was independent of the beta-adrenergic receptors. The ANF-stimulated short-circuit current was found in operculi pretreated with tetrodotoxin (10(-6) or 10(-5) M) or diltiazem (10(-4) M) indicating the ANF response was not due to nerve stimulation. Pretreatment of opercular tissue with dibutyryl adenosine 3',5'-cyclic monophosphate, 8-bromoadenosine 3',5'-cyclic monophosphate, or 8-bromoguanosine 3',5'-cyclic monophosphate (10(-4) M) had no effect on the ANF stimulatory response. Opercular epithelia from short-term freshwater-adapted killifish also showed the ANF-induced response. The stimulation of chloride secretion in Fundulus heteroclitus chloride cells by ANF may have a role in teleost ion regulation.

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