Effects of luminal thymol on epithelial transport in human and rat colon

2011 ◽  
Vol 300 (6) ◽  
pp. G1132-G1143 ◽  
Author(s):  
Izumi Kaji ◽  
Shin-ichiro Karaki ◽  
Atsukazu Kuwahara
Keyword(s):  
Ion Transport ◽  
Transient Receptor Potential ◽  
Epithelial Transport ◽  
Ussing Chamber ◽  
Rat Colon ◽  
Small Intestinal Mucosa ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Anion Secretion ◽  
Serotonin Secretion

Gut lumen is continually exposed to a great variety of agents, including noxious compounds. Chemical receptors that detect the luminal environment are thought to play an important role as sensors and to modulate gastrointestinal functions. Recently, it has been reported that odorant receptors (ORs) are expressed in the small intestinal mucosa and that odorants stimulate serotonin secretion. However, ion transport in the responses to odorants has rarely been discussed, particularly in relation to the large intestine. In the present study, we examined the effects of the OR ligand thymol on ion transport in human and rat colonic epithelia using an Ussing chamber. In the mucosal-submucosal preparations, the mucosal addition of thymol evoked anion secretion concentration dependently. In addition, dextran (4 kDa) permeability was enhanced by the mucosal treatment with thymol. The response to thymol was not affected by tetrodotoxin (TTX) or piroxicam treatments in human or rat colon. Thymol-evoked electrogenic anion secretion was abolished under Ca2+-free conditions or mucosal treatment with transient receptor potential (TRP) A1 blocker (HC-030031). Pretreatment of thymol did not affect electrical field stimulation-evoked anion secretion but significantly attenuated short-chain fatty acid-evoked secretion in a concentration-dependent manner. OR1G1 and TRPA1 expression was investigated in isolated colonic mucosa by RT-PCR. The present results provide evidence that the OR ligand thymol modulates epithelial permeability and electrogenic anion secretion in human and rat colon. The anion secretion by luminal thymol is most likely mediated by direct activation of TRPA1 channel. We suggest that the sensing and responding to odorants in the colon also plays a role in maintaining intestinal homeostasis.

scholarly journals Activation of TRPA1 by luminal stimuli induces EP4-mediated anion secretion in human and rat colon

2012 ◽  
Vol 302 (7) ◽  
pp. G690-G701 ◽  
Author(s):  
Izumi Kaji ◽  
Yukiko Yasuoka ◽  
Shin-ichiro Karaki ◽  
Atsukazu Kuwahara
Keyword(s):  
Host Defense ◽  
Transient Receptor Potential ◽  
Defense Mechanism ◽  
Ussing Chamber ◽  
Pcr Analysis ◽  
Rat Colon ◽  
Receptor Subtype ◽  
Neural Pathways ◽  
Dependent Manner ◽  
Anion Secretion

In gastrointestinal (GI) physiology, anion and fluid secretion is an important function for host defense and is induced by changes in the luminal environment. The transient receptor potential A1 (TRPA1) channel is considered to be a chemosensor in several sensory tissues. Although the function of TRPA1 has been studied in GI motility, its contribution to the transepithelial ion transport system has rarely been discussed. In the present study, we investigated the secretory effect of the potential TRPA1 agonist allyl isothiocyanate (AITC) in rat and human colon using an Ussing chamber. The mucosal application of AITC (10−6-10−3 M) induced Cl− and HCO3− secretion in a concentration-dependent manner, whereas the serosal application induced a significantly weaker effect. AITC-evoked anion secretion was attenuated by tissue pretreatment with piroxicam and prostaglandin (PG) E2; however, this secretion was not affected by TTX, atropine, or extracellular Ca2+ depletion. These experiments indicate that TRPA1 activation induces anion secretion through PG synthesis, independent of neural pathways in the colon. Further analysis also indicates that AITC-evoked anion secretion is mediated mainly by the EP4 receptor subtype. The magnitude of the secretory response exhibited segmental heterogeneity in rat colon. Real-time PCR analysis showed the segmental difference was corresponding to the differential expression of EP4 receptor and cyclooxygenase-1 and -2. In addition, RT-PCR, in situ hybridization, and immunohistochemical studies showed TRPA1 expression in the colonic epithelia. Therefore, we conclude that the activation of TRPA1 in colonic epithelial cells is likely involved in the host defense mechanism through rapid anion secretion.

scholarly journals Cholinergic-induced anion secretion in murine jejunal enteroids involves synergy between muscarinic and nicotinic pathways

2020 ◽  
Vol 319 (2) ◽  
pp. C321-C330
Author(s):  
Kelli Johnson ◽  
Jianyi Yin ◽  
Julie G. In ◽  
Subhash Kulkarni ◽  
Pankaj Pasricha ◽  
...  
Keyword(s):  
Nicotinic Receptors ◽  
Short Circuit ◽  
Ussing Chamber ◽  
Intestinal Transport ◽  
Short Circuit Current ◽  
Muscarinic Agonist ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Anion Secretion ◽  
Qrt Pcr

Acetylcholine induces robust electrogenic anion secretion in mammalian intestine and it has long been hypothesized that it mediates the epithelial response through the M3 and, to a lesser extent, the M1 muscarinic receptors in the mouse. However, nicotinic receptors have recently been identified in intestinal enterocytes by quantitative real-time (qRT)-PCR/RNAseq, although any direct influence on intestinal transport has not been identified. We tested the hypothesis that cholinergic-induced anion secretion in the intestine is a result of both muscarinic and nicotinic pathways that are intrinsic to the intestinal epithelia. We developed a method to generate mouse jejunal enteroid monolayers which were used to measure active electrogenic anion secretion by the Ussing chamber/voltage-clamp technique. Here, we show that the cholinergic agonist carbachol (CCh) and the muscarinic agonist bethanechol (BCh) stimulate short-lived, concentration-dependent anion secretion in the epithelial cell-only enteroid monolayers. The muscarinic antagonist atropine completely inhibited CCh- and BCh-induced secretion, while the nicotinic antagonist hexamethonium reduced the CCh response by ~45%. While nicotine alone did not alter anion secretion, it increased the BCh-induced increase in short-circuit current in a concentration-dependent manner; this synergy was prevented by pretreatment with hexamethonium. In addition to being sensitive to hexamethonium, monolayers express both classes of cholinergic receptor by qRT-PCR, including 13 of 16 nicotinic receptor subunits. Our findings indicate that an interaction between muscarinic and nicotinic agonists synergistically stimulates anion secretion in mouse jejunal epithelial cells and identify a role for epithelial nicotinic receptors in anion secretion.

Secretory effects of a luminal bitter tastant and expressions of bitter taste receptors, T2Rs, in the human and rat large intestine

2009 ◽  
Vol 296 (5) ◽  
pp. G971-G981 ◽  
Author(s):  
Izumi Kaji ◽  
Shin-ichiro Karaki ◽  
Yasuyuki Fukami ◽  
Masaki Terasaki ◽  
Atsukazu Kuwahara
Keyword(s):  
Large Intestine ◽  
Bitter Taste ◽  
Physiological Function ◽  
Ussing Chamber ◽  
Taste Receptor ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Gi Tract ◽  
Concentration Dependent Manner ◽  
Anion Secretion

Taste transduction molecules, such as Gαgust, and taste receptor families for bitter [taste receptor type 2 (T2R)], sweet, and umami, have previously been identified in taste buds and the gastrointestinal (GI) tract; however, their physiological functions in GI tissues are still unclear. Here, we investigated the physiological function and expression of T2R in human and rat large intestine using various physiological and molecular biological techniques. To study the physiological function of T2R, the effect of a bitter compound, 6- n-propyl-2-thiouracil (6-PTU), on transepithelial ion transport was investigated using the Ussing chamber technique. In mucosal-submucosal preparations, mucosal 6-PTU evoked Cl−and HCO3−secretions in a concentration-dependent manner. In rat middle colon, levels of 6-PTU-evoked anion secretion were higher than in distal colon, but there was no such difference in human large intestine. The response to 6-PTU was greatly reduced by piroxicam, but not by tetrodotoxin. Additionally, prostaglandin E2concentration-dependently potentiated the response to 6-PTU. Transcripts of multiple T2Rs (putative 6-PTU receptors) were detected in both human and rat colonic mucosa by RT-PCR. In conclusion, these results suggest that the T2R ligand, 6-PTU, evokes anion secretion, and such response is regulated by prostaglandins. This luminal bitter sensing mechanism may be important for host defense in the GI tract.

SCFA increase intestinal Na absorption by induction of NHE3 in rat colon and human intestinal C2/bbe cells

2001 ◽  
Vol 280 (4) ◽  
pp. G687-G693 ◽  
Author(s):  
Mark W. Musch ◽  
Cres Bookstein ◽  
Yue Xie ◽  
Joseph H. Sellin ◽  
Eugene B. Chang
Keyword(s):  
Brush Border ◽  
Apical Membrane ◽  
Bacterial Flora ◽  
Short Chain Fatty Acids ◽  
Rat Colon ◽  
Dependent Manner ◽  
Soluble Fiber ◽  
Concentration Dependent Manner

Short-chain fatty acids (SCFA), produced by colonic bacterial flora fermentation of dietary carbohydrates, promote colonic Na absorption through mechanisms not well understood. We hypothesized that SCFA promote increased expression of apical membrane Na/H exchange (NHE), serving as luminal physiological cues for regulating colonic Na absorptive capacity. Studies were performed in human colonic C2/bbe (C2) monolayers and in vivo. In C2 cells exposed to butyrate, acetate, proprionate, or the poorly metabolized SCFA isobutyrate, apical membrane NHE3 activity and protein expression increased in a time- and concentration-dependent manner, whereas no changes were observed for NHE2. In contrast, no significant changes in brush-border hydrolase or villin expression were noted. Analogous to the in vitro findings, rats fed the soluble fiber pectin exhibited a time-dependent increase in colonic NHE3, but not NHE2, protein, mRNA, and brush-border activity. These changes were region-specific, as no changes were observed in the ileum. We conclude that luminal SCFA are important physiological cues for regulating colonic Na absorptive function, allowing the colon to adapt to chronic changes in dietary carbohydrate and Na loads.

scholarly journals Regulation of electrolyte transport across cultured endometrial epithelial cells by prolactin

2008 ◽  
Vol 197 (3) ◽  
pp. 575-582 ◽  
Author(s):  
Chatsri Deachapunya ◽  
Sutthasinee Poonyachoti ◽  
Nateetip Krishnamra
Keyword(s):  
Epithelial Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Disulfonic Acid ◽  
Maximum Effect ◽  
Channel Blockers ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Anion Secretion ◽  
Endometrial Epithelial Cells

The effect of prolactin (PRL) on ion transport across the porcine glandular endometrial epithelial cells was studied in primary cell culture using the short-circuit current technique. Addition of 1 μg/ml PRL either to the apical solution or to the basolateral solution produced a peak followed by a sustained increase in Isc, but with a lesser response when PRL was added apically. Basolateral addition of PRL increased the Isc in a concentration-dependent manner with a maximum effect at 1 μg/ml and an effective concentration value of 120 ng/ml. The PRL-stimulated Isc was significantly reduced by pretreatment with an apical addition of 5-nitro-2-(3-phenylpropylamino) benzoic acid (200 μM), diphenylamine-2-carboxylic acid (1 mM) or 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (200 μM), Cl− channel blockers, but not by amiloride (10 μM), a Na+ channel blocker. In addition, pretreatment with bumetanide (200 μM), a Na+–K+–2Cl− cotransporter inhibitor, in the basolateral solution significantly reduced the PRL-stimulated Isc. Replacement of Cl− or in the bathing solutions also decreased the Isc response to PRL. Pretreatment of the monolayer with AG490 (50 μM), an inhibitor of JAK2 activity significantly inhibited the PRL-induced increase in Isc. Western blot analysis of the porcine endometrial epithelial cells revealed the presence of short isoform of PRL receptor (PRLR-S) that could be regulated by 17β-estradiol. The results of this investigation showed that PRL acutely stimulated anion secretion across the porcine endometrial epithelial cells possibly through PRLR-S present in both apical and basolateral membranes. The PRL response appeared to be mediated by the JAK2-dependent pathway.

Role of somatostatin neurons in intestinal peristalsis: facilitatory interneurons in descending pathways

1987 ◽  
Vol 253 (4) ◽  
pp. G434-G438 ◽  
Author(s):  
J. R. Grider ◽  
A. Arimura ◽  
G. M. Makhlouf
Keyword(s):  
Circular Muscle ◽  
Final Concentration ◽  
Rat Colon ◽  
Dependent Manner ◽  
Descending Pathways ◽  
Concentration Dependent Manner ◽  
Intestinal Peristalsis ◽  
Somatostatin Neurons

The role of somatostatin neurons in the regulation of peristalsis was examined in segments of rat colon that permit separate characterization of the ascending contraction and descending relaxation components of the peristaltic reflex. Release of somatostatin and vasoactive intestinal peptide (VIP) increased significantly only during descending relaxation. Preincubation of the segment with somatostatin antiserum (final concentration 1:40) decreased VIP release and descending relaxation. Addition of somatostatin (1 nM to 1 microM) augmented VIP release and descending relaxation in a concentration-dependent manner. Together the results implied that the increase in somatostatin release was coupled to, and responsible for, the increase in VIP release, which in turn was responsible for descending relaxation. The results are consistent with the topography of myenteric VIP neurons (which project into circular muscle) and somatostatin neurons (which project caudad within the plexus) and the pharmacological properties of the two peptides. Somatostatin antiserum had no effect on basal VIP release or ascending contraction, indicating that somatostatin neurons were not involved in the regulation of ascending contraction. The study suggests that somatostatin neurons of the myenteric plexus act as facilitatory interneurons in descending pathways.

Histamine stimulates ion transport by dog pancreatic duct epithelial cells through H1receptors

1998 ◽  
Vol 275 (1) ◽  
pp. G76-G84 ◽  
Author(s):  
Toan D. Nguyen ◽  
Charles N. Okolo ◽  
Mark W. Moody
Keyword(s):  
Epithelial Cells ◽  
Ion Transport ◽  
Receptor Antagonist ◽  
Pancreatic Duct ◽  
Direct Action ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ussing Chambers

Histamine affects pancreatic secretion, but its direct action on ion transport by pancreatic duct epithelial cells (PDEC) has not been defined. We now characterize the secretory effects of histamine on cultured, well-differentiated, and nontransformed dog PDEC. Histamine stimulated, in a concentration-dependent manner (1–100 μM), a cellular125I−efflux that was inhibited by 500 μM 5-nitro-2-(3-phenylpropylamino)benzoic acid, 2.5 mM diphenylamine-2-carboxylate, and 500 μM DIDS and thus mediated through Ca2+-activated Cl− channels. Histamine-stimulated125I−efflux was 1) inhibited by 100 μM diphenhydramine, an H1receptor antagonist, 2) resistant to 1 mM cimetidine, an H2 receptor antagonist, 3) not reproduced by 1 mM dimaprit, an H2 agonist, and 4) inhibited by 50 μM 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-AM, a Ca2+ chelator, suggesting that it was mediated through H1 receptors acting via increased cytosolic Ca2+. Histamine also stimulated a86Rb+efflux that was sensitive to 100 nM charybdotoxin and thus mediated through Ca2+-activated K+ channels. When PDEC monolayers were studied in Ussing chambers, a short-circuit current of 21.7 ± 3.1 μA/cm2 was stimulated by 100 μM histamine. This effect was inhibited by diphenhydramine but not cimetidine, was not reproduced with dimaprit, and was observed only after serosal addition of histamine, suggesting that it was mediated by basolateral H1 receptors on PDEC. In conclusion, histamine, acting through basolateral H1 receptors, activates both Ca2+-activated Cl− and K+ channels; in this manner, it may regulate PDEC secretion in normal or inflamed pancreas.

TRPM8 activation suppresses cellular viability in human melanoma

2008 ◽  
Vol 295 (2) ◽  
pp. C296-C301 ◽  
Author(s):  
Hisao Yamamura ◽  
Shinya Ugawa ◽  
Takashi Ueda ◽  
Akimichi Morita ◽  
Shoichi Shimada
Keyword(s):  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Melanoma Cells ◽  
Human Melanoma ◽  
Specific Gene ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Trpm8 Channel ◽  
Transient Receptor Potential Melastatin ◽  
Inward Currents

The transient receptor potential melastatin subfamily (TRPM), which is a mammalian homologue of cell death-regulated genes in Caenorhabditis elegans and Drosophila, has potential roles in the process of the cell cycle and regulation of Ca2+ signaling. Among this subfamily, TRPM8 (also known as Trp-p8) is a Ca2+-permeable channel that was originally identified as a prostate-specific gene upregulated in tumors. Here we showed that the TRPM8 channel was expressed in human melanoma G-361 cells, and activation of the channel produced sustainable Ca2+ influx. The application of menthol, an agonist for TRPM8 channel, elevated cytosolic Ca2+ concentration in a concentration-dependent manner with an EC50 value of 286 μM in melanoma cells. Menthol-induced responses were significantly abolished by the removal of external Ca2+. Moreover, inward currents at a holding potential of −60 mV in melanoma cells were markedly potentiated by the addition of 300 μM menthol. The most striking finding was that the viability of melanoma cells was dose-dependently depressed in the presence of menthol. These results reveal that a functional TRPM8 protein is expressed in human melanoma cells to involve the mechanism underlying tumor progression via the Ca2+ handling pathway, providing us with a novel target of drug development for malignant melanoma.

Parathyroid hormone (PTH) rapidly enhances CFTR-mediated HCO3− secretion in intestinal epithelium-like Caco-2 monolayer: a novel ion regulatory action of PTH

2011 ◽  
Vol 301 (1) ◽  
pp. C137-C149 ◽  
Author(s):  
Suparerk Laohapitakworn ◽  
Jirawan Thongbunchoo ◽  
La-iad Nakkrasae ◽  
Nateetip Krishnamra ◽  
Narattaphol Charoenphandhu
Keyword(s):  
Plasma Membrane ◽  
Parathyroid Hormone ◽  
Protein Kinase ◽  
Intestinal Epithelium ◽  
Epithelial Transport ◽  
Ussing Chamber ◽  
Membrane Resistance ◽  
Regulatory Action ◽  
Dependent Manner ◽  
Gf 109203X

Besides being a Ca2+-regulating hormone, parathyroid hormone (PTH) has also been shown to regulate epithelial transport of certain ions, such as Cl−, HCO3−, and Na+, particularly in the kidney. Although the intestinal epithelium also expressed PTH receptors, little was known regarding its mechanism in the regulation of intestinal ion transport. We investigated the ion regulatory role of PTH in intestinal epithelium-like Caco-2 monolayer by Ussing chamber technique and alternating current impedance spectroscopy. It was found that Caco-2 cells rapidly responded to PTH within 1 min by increasing apical HCO3− secretion. CFTR served as the principal route for PTH-stimulated apical HCO3− efflux, which was abolished by various CFTR inhibitors, namely, NPPB, glycine hydrazide-101 (GlyH-101), and CFTRinh-172, as well as by small interfering RNA against CFTR. Concurrently, the plasma membrane resistance was decreased with no changes in the plasma membrane capacitance or paracellular permeability. HCO3− was probably supplied by basolateral uptake via the electrogenic Na+-HCO3− cotransporter and by methazolamide-sensitive carbonic anhydrase, while the resulting intracellular H+ might be extruded by both apical and basolateral Na+/H+ exchangers. Furthermore, the PTH-stimulated HCO3− secretion was markedly reduced by protein kinase A (PKA) inhibitor (PKI 14–22 amide) and phosphoinositide 3-kinase (PI3K) inhibitors (wortmannin and LY-294002), but not by intracellular Ca2+ chelator (BAPTA-AM) or protein kinase C inhibitor (GF-109203X). In conclusion, the present study provided evidence that PTH directly and rapidly stimulated apical HCO3− secretion through CFTR in PKA- and PI3K-dependent manner, which was a novel noncalciotropic, ion regulatory action of PTH in the intestinal epithelium.

scholarly journals Stimulation of mucosal secretion by lubiprostone (SPI-0211) in guinea pig small intestine and colon

2009 ◽  
Vol 296 (4) ◽  
pp. G823-G832 ◽  
Author(s):  
Guijun Fei ◽  
Yu-Zhong Wang ◽  
Sumei Liu ◽  
Hong-Zhen Hu ◽  
Guo-Du Wang ◽  
...  
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Short Circuit ◽  
Enteric Neurons ◽  
Resting Membrane Potential ◽  
Small Intestinal Mucosa ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Mucosal Secretion ◽  
Stimulation Of

Actions of lubiprostone, a selective type-2 chloride channel activator, on mucosal secretion were investigated in guinea pig small intestine and colon. Flat-sheet preparations were mounted in Ussing flux chambers for recording short-circuit current ( Isc) as a marker for electrogenic chloride secretion. Lubiprostone, applied to the small intestinal mucosa in eight concentrations ranging from 1–3000 nM, evoked increases in Isc in a concentration-dependent manner with an EC50 of 42.5 nM. Lubiprostone applied to the mucosa of the colon in eight concentrations ranging from 1–3000 nM evoked increases in Isc in a concentration-dependent manner with an EC50 of 31.7 nM. Blockade of enteric nerves by tetrodotoxin did not influence stimulation of Isc by lubiprostone. Antagonists acting at prostaglandin (PG)E2, EP1–3, or EP4 receptors did not suppress stimulation of Isc by lubiprostone but suppressed or abolished PGE2-evoked responses. Substitution of gluconate for chloride abolished all responses to lubiprostone. The selective CFTR channel blocker, CFTR(inh)-172, did not suppress lubiprostone-evoked Isc. The broadly acting blocker, glibenclamide, suppressed ( P < 0.001) lubiprostone-evoked Isc. Lubiprostone, in the presence of tetrodotoxin, enhanced carbachol-evoked Isc. The cholinergic component, but not the putative vasoactive intestinal peptide component, of neural responses to electrical field stimulation was enhanced by lubiprostone. Application of any of the prostaglandins, E2, F2, or I2, evoked depolarization of the resting membrane potential in enteric neurons. Unlike the prostaglandins, lubiprostone did not alter the electrical behavior of enteric neurons. Exposure to the histamine H2 receptor agonists increased basal Isc followed by persistent cyclical increases in Isc. Lubiprostone increased the peak amplitude of the dimaprit-evoked cycles.

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