A novel role of intestine epithelial GABAergic signaling in regulating intestinal fluid secretion

2012 ◽  
Vol 303 (4) ◽  
pp. G453-G460 ◽  
Author(s):  
Yan Li ◽  
Yun-Yan Xiang ◽  
Wei-Yang Lu ◽  
Chuanyong Liu ◽  
Jingxin Li
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Intestinal Epithelium ◽  
Fluid Secretion ◽  
Signaling Proteins ◽  
Intestinal Epithelial ◽  
Intestinal Fluid ◽  
Patch Clamp Recording ◽  
Gaba Signaling ◽  
Intestinal Fluid Secretion

γ-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system, and it is produced via the enzymatic activity of glutamic acid decarboxylase (GAD). GABA generates fast biological signaling through type A receptors (GABAAR), an anionic channel. Intriguingly, GABA is found in the jejunum epithelium of rats. The present study intended to determine whether a functional GABA signaling system exists in the intestinal epithelium and if so whether the GABA signaling regulates intestinal epithelial functions. RT-PCR, Western blot, and immunohistochemical assays of small intestinal tissues of various species were performed to determine the expression of GABA-signaling proteins in intestinal epithelial cells. Perforated patch-clamp recording was used to measure GABA-induced transmembrane current in the small intestine epithelial cell line IEC-18. The fluid weight-to-intestine length ratio was measured in mice that were treated with GABAAR agonist and antagonist. The effect of GABAAR antagonist on allergic diarrhea was examined using a mouse model. GABA, GAD, and GABAAR subunits were identified in small intestine epithelial cells of mice, rats, pigs, and humans. GABAAR agonist induced an inward current and depolarized IEC-18. Both GABA and the GABAAR agonist muscimol increased intestinal fluid secretion of rats. The increased intestinal secretion was largely decreased by the GABAAR antagonist picrotoxin or gabazine, but not by tetrodotoxin. The expression levels of GABA-signaling proteins were increased in the intestinal epithelium of mice that were sensitized and challenged with ovalbumin (OVA). The OVA-treated mice exhibited diarrhea, which was alleviated by oral administration of gabazine or picrotoxin. An endogenous autocrine GABAergic signaling exists in the mammalian intestinal epithelium, which upregulates intestinal fluid secretion. The intestinal GABAergic signaling becomes intensified in allergic diarrhea, and inhibition of this GABA-signal system alleviates the allergic diarrhea.

scholarly journals Human Intestinal Epithelial Cells Respond toCryptosporidium parvum Infection with Increased Prostaglandin H Synthase 2 Expression and Prostaglandin E2and F2α Production

1998 ◽  
Vol 66 (4) ◽  
pp. 1787-1790 ◽  
Author(s):  
Fabrice Laurent ◽  
Martin F. Kagnoff ◽  
Tor C. Savidge ◽  
Muriel Naciri ◽  
Lars Eckmann
Keyword(s):  
Epithelial Cells ◽  
Animal Species ◽  
Intestinal Epithelial Cells ◽  
Fluid Secretion ◽  
Prostaglandin E ◽  
Intestinal Epithelial ◽  
Prostaglandin H Synthase ◽  
Human Intestinal Epithelial Cells ◽  
Intestinal Fluid Secretion ◽  
Prostaglandin H

ABSTRACT Cryptosporidium parvum is an important cause of diarrhea in humans and several animal species. Prostaglandins play a central role in regulating intestinal fluid secretion in animal models of cryptosporidiosis, but their cellular sources and mechanisms of induction are unclear. Here, we show that C. parvuminfection directly activates prostaglandin H synthase 2 expression and prostaglandin E2 and F2α production in human intestinal epithelial cells.

The protease phenotype and crystalline nature of the granules of intraepithelial mast cells in Trichinella spiralis-infected mice

1995 ◽  
Vol 53 ◽  
pp. 818-819
Author(s):  
D.S. Friend ◽  
N. Ghildyal ◽  
M.F. Gurish ◽  
K.F. Austen ◽  
R.L. Stevens
Keyword(s):  
Small Intestine ◽  
Mast Cells ◽  
Epithelial Cells ◽  
Lamina Propria ◽  
Trichinella Spiralis ◽  
Intestinal Epithelial ◽  
Carboxypeptidase A ◽  
C3h Mice ◽  
Granule Morphology ◽  
Crystalline Nature

Trichinella spiralis induces a profound mastocytosis and eosinophilia in the small intestine of the infected mouse. Mouse mast cells (MC) store in their granules various combinations of at least five chymotryptic chymases [designated mouse MC protease (mMCP) 1 to 5], two tryptic proteases designated mMCP-6 and mMCP-7 and an exopeptidase, carboxypeptidase A (mMC-CPA). Using antipeptide, protease -specific antibodies to these MC granule proteases, immunohistochemistry was done to determine the distribution, number and protease phenotype of the MCs in the small intestine and spleen 10 to >60 days after Trichinella infection of BALB/c and C3H mice. TEM was performed to evaluate the granule morphology of the MCs between intestinal epithelial cells and in the lamina propria (mucosal MCs) and in the submucosa, muscle and serosa of the intestine (submucosal MCs).As noted in the table below, the number of submucosal MCs remained constant throughout the study. In contrast, on day 14, the number of MCs in the mucosa increased ~25 fold. Increased numbers of MCs were observed between epithelial cells in the mucosal crypts, in the lamina propria and to a lesser extent, between epithelial cells of the intestinal villi.

Effect of leptin on intestinal apolipoprotein AIV in response to lipid feeding

2001 ◽  
Vol 281 (3) ◽  
pp. R753-R759 ◽  
Author(s):  
Takashi Doi ◽  
Min Liu ◽  
Randy J. Seeley ◽  
Stephen C. Woods ◽  
Patrick Tso
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Regional Distribution ◽  
Intestinal Epithelial ◽  
Lipid Infusion ◽  
Intraduodenal Infusion ◽  
Crypt Cells

We determined apolipoprotein AIV (apo AIV) content in intestinal epithelial cells using immunohistochemistry when leptin was administered intravenously. Most of the apo AIV immunoreactivity in the untreated intestine was located in the villous cells as opposed to the crypt cells. Regional distribution of apo AIV immunostaining revealed low apo AIV content in the duodenum and high content in the jejunum that gradually decreases caudally toward the ileum. Intraduodenal infusion of lipid (4 h) significantly increased apo AIV immunoreactivity in the jejunum and ileum. Simultaneous intravenous leptin infusion plus duodenal lipid infusion markedly suppressed apo AIV immunoreactivity. Duodenal lipid infusion increased plasma apo AIV significantly (measured by ELISA), whereas simultaneous leptin infusion attenuated the increase. These findings suggest that leptin may regulate circulating apo AIV by suppressing apo AIV synthesis in the small intestine.

Glucose and glutamine provide similar proportions of energy to mucosal cells of rat small intestine

1997 ◽  
Vol 273 (4) ◽  
pp. G968-G978 ◽  
Author(s):  
Sharon E. Fleming ◽  
Kirsten L. Zambell ◽  
Mark D. Fitch
Keyword(s):  
Small Intestine ◽  
Epithelial Cells ◽  
Metabolic Pathways ◽  
Glycolytic Flux ◽  
Net Energy ◽  
Intestinal Epithelial ◽  
Atp Production ◽  
Distal Small Intestine ◽  
Mucosal Cells ◽  
In Cells

The objectives of this study were to establish a reliable method for quantifying glycolytic flux in intestinal epithelial cells, to determine the proportion of energy provided to small intestine epithelial cells by glucose vs. glutamine, and to determine whether there was an energetic advantage to having both substrates present simultaneously. There was substantial retention of 3H in alanine and lactate when [2-3H]glucose was used as tracer for quantifying glycolysis, and the magnitude of the3H retention was influenced by the presence of other substrates and metabolites. Detritiation was at least 99% complete, however, when [3-3H]glucose was used as tracer in this system and the tritium was recovered as3H2O. Glycolytic flux was six- to sevenfold higher in cells of the proximal than distal small intestine but was not significantly different for young adult (4 mo) vs. aged adult (24 mo) rats. Net ATP production from exogenous substrates was higher when both glucose and glutamine were present simultaneously than when either substrate was present alone, and glucose was calculated to provide 50–60% of the net ATP produced from these two substrates. Most of the energy produced from glucose was produced via the anaerobic metabolic pathways (78% for glucose alone, 95% with glucose and glutamine). Net energy production was calculated to be 10% lower in cells from aged animals than in those from young animals, since CO2 production from these major substrates was lower in cells from aged animals.

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