Involvement of K+ channel modulation in the proabsorptive effect of nitric oxide in the rat jejunum in vivo

Schirgi‐Degen, Andrea; Beubler, Eckhard

doi:10.1016/s0014-2999(96)00683-8

Cited by 22 publications

(17 citation statements)

References 24 publications

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“…Since L-NAME alone (in the absence of ANG II) did not alter jejunal fluid absorption and AT 2 receptor blockade did not prevent the increase in absorption with L-ARG, we conclude that ANG II increases absorption by AT 2 receptor-mediated nitric oxide production. Our results are consistent with the recent reports of Schirgi-Degen and Beubler (19,20) that nitric oxide enhances fluid absorption in the rat intestine. In contradistinction to these findings regarding the intravenous…”

Section: Discussionsupporting

confidence: 94%

Compartmentalization of extracellular cGMP determines absorptive or secretory responses in the rat jejunum

Jin

Siragy²,

Guerrant³

et al. 1999

J. Clin. Invest.

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Angiotensin II (ANG II) regulates sodium and water transport across epithelial cells in the kidney and gastrointestinal tract (1-5). In the jejunum, low concentrations of ANG II stimulate sodium and water absorption while high concentrations inhibit absorption and/or stimulate secretion (3). We have recently demonstrated that ANG II stimulates absorption in the jejunum by an action at the AT 2 receptor involving the generation of guanosine cyclic 3′,5′-monophosphate (cGMP) (3,6,7).In this study, we hypothesized that ANG II increases jejunal sodium and water absorption by increasing the synthesis of nitric oxide (NO) and stimulating soluble guanylyl cyclase. However, since cGMP is thought to mediate secretory, not absorptive, responses in the gastrointestinal tract when particulate guanylyl cyclase (GC-C) is stimulated by the heat-stable enterotoxin of Escherichia coli (STa) or guanylin or uroguanylin (8, 9), we hypothesized that the sodium and water transport response, absorptive or secretory, is associated with a compartmentalized cGMP response via either soluble or particulate guanylyl cyclase. If so, STa would stimulate secretion by stimulating particulate guanylyl cyclase on the apical cell membrane of transporting epithelial cells. In contradistinction, nitric oxide would stimulate absorption via soluble guanylyl cyclase from the serosal side, and cGMP would be released predominantly across the basolateral membrane of epithelial cells into the interstitial space. We introduced both in situ loop and microdialysis techniques to test these hypotheses. MethodsAnimal preparation. Male Wistar rats weighing 200 ± 15 g were obtained from Harlan Bioproducts Inc. (Indianapolis, Indiana, USA). Rats were housed in a room with 12-h light-dark cycles and maintained on standard rat chow containing 0.28% NaCl or low-sodium chow containing 0.08% NaCl (BioServe Biotechnologies, Frenchtown, New Jersey, USA). Rats were fasted overnight before the study.Operative procedure. Rats (n = 8 in each group) were anesthetized with pentobarbital sodium 70 mg/kg intraperitoneally (Veterinary Laboratories, Inc., Lenexa, Kansas). The trachea and left jugular vein were cannulated. A venous cannula (PE 50) was connected to a Harvard 975 infusion pump (Harvard Apparatus Co., South Natick, Massachusetts, USA) through which lactated Ringer's solution (vehicle) and drugs were infused. A ventral midline celiotomy also was performed and the jejunum was prepared in two different ways as described below.Single-pass perfusion. These studies were performed according to previous publications (10, 11). An inlet cannula was placed just below the duodenal-jejunal flexure and the outlet cannula was 15 cm distal to the inlet cannula. The lumen just proximal and distal to the cannulated segment was tied off. To measure water transport, lactated Ringer's solution containing [ 14 C]inulin (15,000 dpm/ml; 2.2 µCi/mg specific activity; New England Nuclear, Boston, Massachusetts, USA) and phenol red (50 mg/liter, Sigma Chemical Company; St. Louis, Missouri, We ex...

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Section: Discussionsupporting

confidence: 94%

Compartmentalization of extracellular cGMP determines absorptive or secretory responses in the rat jejunum

Jin

Siragy²,

Guerrant³

et al. 1999

J. Clin. Invest.

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“…Interestingly, in rat small intestine in vivo also a proabsorptive role of NO has been observed. 21,22) The reasons for this discrepancy between the in vivo and the in vitro measurements are completely unknown.…”

Section: Nitric Monoxidementioning

confidence: 99%

Regulation of Colonic Ion Transport by Gasotransmitters

Pouokam

Steidle

Diener

2011

Biological & Pharmaceutical Bulletin

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“…In our experiments L-NAME and also E. coli STa-induced secretion was totally blocked by cromakalim, a K + channel opener. Glibenclamide, a K + channel blocker, induced net fluid secretion and reversed the proabsorptive effect of L-arginine [16].…”

mentioning

confidence: 99%

“…Considering two earlier studies [14,15], we [16] raised the hypothesis that the proabsorptive effect of NO may involve the opening of basolaterally located potassium channels in enterocytes: NO has been demonstrated to activate K + channels in vascular smooth muscle without requiring cGMP. On the other hand, K + channel activators have been observed to decrease Isc in ileal mucosa, indicating a regulatory role of K + channels in electrolyte absorption.…”

mentioning

confidence: 99%