Adrenoceptor-mediated secretion across the rat colonic epithelium

Schultheiß, Gerhard; Diener, Martin

doi:10.1016/s0014-2999(00)00487-8

Cited by 23 publications

(37 citation statements)

References 10 publications

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“…This NKCC1-mediated secretory activity has been linked to both ␤-and ␣ 2 -adrenergic receptors, respectively, through increases in intracellular [cAMP], with a resultant fall in intracellular chloride, and through increases in intracellular [Ca 2ϩ ], with the activation of basolateral K ϩ recycling channels (26).…”

Section: Figmentioning

confidence: 99%

Activation of the Na-K-Cl Cotransporter NKCC1 Detected with a Phospho-specific Antibody

Flemmer¹,

Gíménez

Dowd

et al. 2002

Journal of Biological Chemistry

170

158

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The Na-K-Cl cotransporter NKCC1 is activated by phosphorylation of a regulatory domain in its N terminus. In the accompanying paper (Darman, R. B., and Forbush, B. (2002) J. Biol. Chem. 277, 37542-37550), we identify three phosphothreonines important in this process. Using a phospho-specific antibody (anti-phospho-NKCC1 antibody R5) raised against a diphosphopeptide containing Thr 212 and Thr 217 of human NKCC, we were readily able to monitor the cotransporter activation state. In 32 P phosphorylation experiments with rectal gland tubules, we show that the R5 antibody signal is proportional to the amount of 32 P incorporated into NKCC1; and in experiments with NKCC1-transfected HEK-293 cells, we demonstrate that R5-detected phosphorylation directly mirrors functional activation. Immunofluorescence analysis of shark rectal gland shows activation-dependent R5 antibody staining along the basolateral membrane. In perfused rat parotid glands, isoproterenol induced staining of both acinar and ductal cells along the basolateral membrane. Isoproterenol also induced basolateral staining of the epithelial cells in rat trachea, whereas basal cells in the subepithelial tissue displayed heavy, non-polarized staining of the cell membrane. In rat colon, agonist stimulation induced staining along the basolateral membrane of crypt cells. These data provide direct evidence of NKCC1 regulation in these tissues, and they further link phosphorylation of NKCC1 with its activation in transfected cells and native tissue. The high conservation of the regulatory threonine residues among NKCC1, NKCC2, and NCC family members, together with the fact that tissues from divergent vertebrate species exhibit similar R5-binding profiles, lends further support to the role of this regulatory locus in vivo. NKCC1, the secretory or housekeeping isoform of the Na-K-Cl cotransporter, is expressed in most cell types, aiding in the regulation of cell volume. In polarized cells of secretory epithelia, NKCC1 is heavily expressed along the basolateral membrane, activated in response to secretagogues, and paramount for the transepithelial secretion of Cl Ϫ and water (2). NKCC1-mediated Cl Ϫ secretion has been well documented in rat parotid gland (3, 4), shark rectal gland (5), rat colon (6), and dog trachea (7). At least in shark rectal gland, the evidence is consistent with an indirect activation of NKCC1 upon agonist stimulation: secretagogues cause a drop in intracellular [Cl Ϫ ] and volume via protein kinase A-mediated phosphorylation of apical chloride channels; in turn, low intracellular [Cl Ϫ ] and low cell volume provide activation stimuli for the currently unidentified NKCC1 kinase(s) (2, 8).Our laboratory (9) and others (10) have linked the phosphorylation of the intracellular N-terminal domain with NKCC1 activation. In the accompanying paper, Darman and Forbush (1) describe the phosphorylation of three residues in this regulatory domain, of which Thr 184 and Thr 189 are necessary for maximal sNKCC1 1 activation. Thr 189 in particular is demonstra...

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Section: Figmentioning

confidence: 99%

Activation of the Na-K-Cl Cotransporter NKCC1 Detected with a Phospho-specific Antibody

Flemmer¹,

Gíménez

Dowd

et al. 2002

Journal of Biological Chemistry

170

158

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“…Several investigators have reported the expression of hadrenergic receptors in normal colon tissue (16,17) but their modulatory action on cancer growth and their relationship to smoking-related colorectal cancer are elusive. In the present study, the modulatory roles of NNK in HT-29 colon cancer cell proliferation were clarified.…”

Section: Introductionmentioning

confidence: 99%

4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone from Cigarette Smoke Stimulates Colon Cancer Growth via β-Adrenoceptors

et al. 2005

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Cigarette smoking is a risk factor for colorectal cancer. It is suggested that 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific nitrosamine, mediates the carcinogenic action of cigarette smoking by promoting cancer growth. In the present study, the proliferative response of a cultured colon cancer cell line HT-29 to NNK was determined. It was found that NNK dose-dependently stimulated HT-29 cell proliferation. In this regard, the stimulatory action of NNK was abolished by atenolol and ICI 118,551, a B 1 -and B 2 -selective antagonist, respectively. In addition, cell growth was stimulated by the nonselective adrenergic agonist, noradrenaline, and more effectively by the B-selective agonist, isoproterenol. The second message cyclic AMP level for B-adrenoceptor activation was elevated by isoproterenol and NNK treatment. These agents also up-regulated cyclooxygenase-2 expression, cytosolic phospholipase A 2 expression, and prostaglandin E 2 release. B 2 -adrenoceptor blockade with ICI 118,551, in contrast, significantly decreased cyclooxygenase-2 expression, cytosolic phospholipase A 2 expression and prostaglandin E 2 release induced by NNK and isoproterenol. To conclude, it is proposed that NNK stimulates HT-29 cell proliferation through B-adrenoceptors, preferentially B 2 receptors. Activation of the B-adrenoceptors, and the consequent cyclic AMP elevation coupled with the downstream arachidonic acid pathway, is perhaps an important mechanistic cascade in the promotion of colon cancer growth. These findings partly elucidate the carcinogenic actions of cigarette smoke and shed new light on the novel modulatory role of B-adrenoceptors in the development of colon cancer. (Cancer Res 2005; 65(12): 5272-7)

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“…Norepinephrine produced segment-specific effects on ion transport via different kind of receptors. 9) However, most studies were undertaken to investigate the differences between the proximal and distal colon 3,10) or between the colon and rectum.…”

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Segmental Heterogeneity of Epithelial Ion Transport Induced by Stimulants in Rat Distal Colon

Yang

Xue

Guo

et al. 2006

Biological & Pharmaceutical Bulletin

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Mammalian colon plays an important role in electrolytes and water balance, and exhibits significant segmental heterogeneity along its longitudinal axis.1) The mucosa of the colonic inner surface is a typical electrolyte-transporting epithelium, which is able to move large quantities of ion and water from the mucosal side to the blood side and vice versa.2) It has been reported that the net absorption of water, sodium and chloride, 3) as well as amiloride-sensitive shortcircuit current (I SC ) 4) was dominant in distal colon than that in proximal colon, and the same activators could induce various responses in the different segments of colon. 1,6) Nobles et al. reported that the distal segments of the rat colon were more sensitive to carbachol (CCh), a Ca 2ϩ pathway activator, as well as forskolin, a cAMP pathway activator 5) which provide the evidences for the segmental specificity with regard to the intracellular signaling pathway responsible for the activation of secretion. Using PCR technique, Greig et al. found that the expression of ENaC (epithelial Na ϩ channel) was different between the rat proximal colon and distal colon. 7)Recently, the segmental heterogeneity of endogenous prostaglandin was also reported to contribute to the differences in human colon secretory responses. 1)Ion transport in gastrointestinal tract is under the control of neurotransmitters and hormones.8) The distribution of various kinds of receptors is also different in both segments of distal and proximal colon. Norepinephrine produced segment-specific effects on ion transport via different kind of receptors. 9) However, most studies were undertaken to investigate the differences between the proximal and distal colon 3,10) or between the colon and rectum.11) During our study, we found that even within the rat distal colon, the responses difference to stimulants also existed in the different segments. But there are a limited number of studies performed to compare the distinction. In the present study, the segmental heterogeneity of epithelial responses to different stimulants and its possible mechanism were investigated in rat distal colon. MATERIALS AND METHODS SolutionsThe Ussing chamber experiments were carried out in Krebs-Henseleit solution (K-HS) contained (in mM): NaCl, 117; KCl, 4.7; MgCl 2 , 1.2; KH 2 PO 4 , 1.2; NaHCO 3 , 24.8; CaCl 2 , 2.5; glucose, 11.1. The solution was bubbled with 95% O 2 -5% CO 2 to maintain the pH of the solution at 7.4; temperature at 37°C. Tissue Preparation Animal protocols followed guidelines established by the NIH and were approved by Animal Care and Use Committee, Capital University of Medical Sciences. Adult male Sprague-Dawley rats (Laboratory Animal Services Center, Capital University of Medical Sciences) ranging in weight from 200 to 300 g had free access to standard rodent laboratory food and water until the day of the experiments. The animals were killed by cervical dislocation. The distal colon was removed and defined as the ca. 7 cmlong segment proximal to the lymph node (typically situat...

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Adrenoceptor-mediated secretion across the rat colonic epithelium

Cited by 23 publications

References 10 publications

Activation of the Na-K-Cl Cotransporter NKCC1 Detected with a Phospho-specific Antibody

Activation of the Na-K-Cl Cotransporter NKCC1 Detected with a Phospho-specific Antibody

4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone from Cigarette Smoke Stimulates Colon Cancer Growth via β-Adrenoceptors

Segmental Heterogeneity of Epithelial Ion Transport Induced by Stimulants in Rat Distal Colon

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