62 Female Gender Favors Activation of Gut Immune and Barrier Regulatory Networks
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AGA Abstracts were also used to evaluate their effect on Caco-2 paracellular permeability. RESULTS : IFN- γ mRNA expression was significantly higher in patients with IBS compared to HC (2-ΔΔCt= 2.57±0.6 vs 2-ΔΔCt=0.66±0.1; P<0.05). In addition, we showed increased protein levels of IFN-γ in biopsy homogenates of patients with IBS vs HC (increase of 48% in IBS-D;P<0.05). Similarly, we demonstrated a higher concentration of IFN-γ protein in IBS supernatants. The treatment of Caco-2 cells with IBS supernatants induced a significant decrease in SERT expression compared to HC supernatants. IBS supernatants produced an increase in Caco- 2 cell permeability. The effects of IBS supernatants on Caco-2 cells were mediated, at least in part, by IFN-γ. CONCLUSIONS : We demonstrated an increased expression of IFN-γ in the colonic mucosa of patients with IBS. We also showed increased IFN-γ amount both in biopsies and supernatants of patients with IBS. Epithelial permeability was enhanced by IBS supernatants which induced also a reduction of SERT expression, at least in part via IFN- γ. All together, these data suggest a potential role of IFN-γ in IBS pathophysiology. 62 Female Gender Favors Activation of Gut Immune and Barrier Regulatory Networks Carmen Alonso, Marc Pigrau, María Vicario, Beatriz Lobo, Cristina Frias, Ana María González-Castro, Eloísa Salvo-Romero, Cesar Sevillano, Cristina Martinez, Bruno Kotska Rodiño-Janeiro, Fernando Azpiroz, Javier Santos INTRODUCTION: Irritable bowel syndrome (IBS) is a highly prevalent disorder, linked to intestinal epithelial dysfunction and mucosal microinflammation, with unexplained increased women susceptibility. We have demonstrated that female gender per se determines intestinal barrier dysfunction in response to acute experimental stress. This response could represent, in susceptible individuals, an early stage towards the onset of functional digestive diseases. AIMS&METHODS: We aim to identify gender-dependent molecular biomarkers of intestinal barrier dysfunction in response to acute stress in healthy individuals to understand the mechanistic origin of increased female prevalence in IBS. METHODS: Twelve men (M) and 12 age-matched females (F) were recruited. In each participant, two consecutive jejunal biopsies were obtained by Watson's capsule: one at baseline and another 90 min after 15 min of intermittent cold pain stress (CPS). Throughout the study, autonomic (blood pressure and heart rate), hormonal (plasma cortisol) and psychological responses (Subjective Stress Rating Scale) to CPS were monitored. Mucosal RNA was isolated and submitted to microarray analysis followed by differential gene expression and biological pathways identification. RESULTS: CPS induced a significant autonomic response identified by increased heart rate, blood pressure and plasma cortisol, in association with elevated stress perception in all participants. Interestingly, gene expression studies uncovered differential responses to stress between M and F. Particularly, in the female group, CPS induced circadian rhythm regulation (P<0.00001), along with NK and T cell activation (NFIL3: 1.8; MAL: 1.8 fold change vs basal), and changes in epithelial integrity proteins (KRT13: 1.9 fold change vs basal). In the male group, the stress response was associated with urea cycle and aminoacid metabolism activation (P<0.005), and upregulation of antioxidant genes (SOD1: 1.9 fold change vs basal). CONCLUSION: Acute experimental stress highlights gender-specific molecular responses involving immune activity and regulation of epithelial integrity in healthy gut, responses that may be linked to female predominance in IBS. 63 Duodenal Acid Perfusion in Healthy Volunteers Results in Mast Cell Activation and Increased Permeability Hanne Vanheel, Tim Vanuytsel, María Vicario, Eveline Deloose, Jan F. Tack, Ricard Farré Background: Functional dyspepsia (FD) is characterised by a variety of symptoms localised in the epigastric region. We recently reported (Vanheel et al, Gut 2013) that patients with FD show impaired duodenal integrity, associated with low-grade inflammation. A potential cause underlying impaired duodenal barrier function in FD may be the increased duodenal acid exposure that has been demonstrated in these patients (Lee et al, AJG 2004). Our aim was to evaluate the effect of duodenal acid perfusion on duodenal integrity and immune activation in healthy volunteers. To assess activation of duodenogastric reflex pathways (Vanuytsel et al, NMO 2013), we also measured intragastric pressure (IGP). Methods: Ten healthy volunteers (3 men; age 34.6±4.2 years) participated in the study. An infusion tube was positioned in the second part of the duodenum and a high resolution manometry probe was positioned in the stomach to measure IGP. HCl 0.1 N or 0.9% saline was infused in the duodenum during 30 min at a rate of 5 mL/min in a randomized, double-blind manner. Thirty minutes after infusion, endoscopic duodenal biopsy specimens were obtained to measure transepithelial electrical resistance and paracellular permeability for fluorescein- labeled dextrans (MW 4 kDa) in Ussing chambers. Expression of tight junction proteins in biopsy specimens was evaluated at gene level by real-time RT-PCR (claudin 1-4, occludin, zonula occludens 1-3 and myosin light-chain kinase) and at protein level by western blot (claudin 1-4). Activation of mast cells and eosinophils was assessed by measuring tryptase and eosinophilic major basic protein respectively, both at mRNA and protein level. Differences between groups were analyzed using paired t tests or Wilcoxon signed rank tests when appropriate. Results: Compared with saline infusion, acid perfusion significantly lowered transepithelial electrical resistance (17.8±0.7 V.cm 2 vs. 23.0±1.0 Ω.cm 2 , p=0.006) and increased passage of fluorescein-labeled dextrans (57.4±7.5pmol vs. 31.8±4.6pmol, p=0.01) of duodenal biopsy specimens. No difference in gene expression of tight junction proteins, tryptase and eosinophilic major basic protein was detected. However, compared with saline infusion, protein expression of claudin 3 was lower (0.55 fold; p=0.002) and tryptase expression was higher (1.86 fold; p=0.0008) after acid perfusion. In addition, IGP was significantly lower during acid perfusion compared with saline infusion (p=0.02). Conclu- sion: Duodenal acid perfusion in healthy volunteers disrupts epithelial integrity and activates mucosal mast cells. This response could underlie altered permeability and low-grade inflam- mation observed in FD. Hence, increased duodenal acid exposure in patients with FD is a potential pathophysiological mechanism contributing to dyspeptic symptom generation. S-18 AGA Abstracts 64 RNA Sequencing Shows Transcriptomic Changes in Rectosigmoid Mucosa in Patients With Irritable Bowel Syndrome-Diarrhea Andres Acosta, Paula Carlson, Irene A. Busciglio, Simon J. Gibbons, Gianrico Farrugia, Eric W. Klee, Michael Camilleri Background: Changes in mucosal biology in patients with IBS-diarrhea (IBS-D) include immune activation, barrier dysfunction and increased fluid secretion. The underlying mecha- nisms are unclear. Aim: To compare expression of mRNA in rectosigmoid mucosa from 9 female IBS-D patients [with accelerated colonic transit (CT)] and 9 female healthy controls (with normal CT), and identify other biologically relevant transcriptome changes. Method: We used stored samples from 9 patients with rapid CT (geometric center, GC24: 4.19-4.92) and 9 controls with normal CT (GC24: 1.15-2.63). RNA was sequenced (RNA-Seq) on Illumina HiSeq 2000 using TruSeq SBS Sequencing Kit Version 3. Analysis of each sample [alignment statistics, in-depth quality control metrics, gene and exon expression levels, fusion transcripts and single nucleotide variants (SNVs)] was done using Mayo Clinic's MAPR Seq v1.0, a computational workflow for analysis of RNA-Seq. Gene expression variation was examined by edgeR in the following "targeted" genes associated with IBS in the literature: 5-HTTLPR, TNFSF15, FAAH, CNR1, KLB, FGFR4, GPBAR1, TLR9, C11orf30, ORMDL3, NPSR1, and HLA 2/8. Associations of IBS-D with any other gene mRNA was compared to control expression by edgeR, independent of any a priori hypothesis. Ingenuity and Canonical Pathway Analyses were conducted on mRNA of 21 genes significant after FDR (p=0.034). Results: Of the 12 "targeted" genes tested, patients with IBS-D had increased mRNA expres- sion of TNFSF15 (fold change 1.53, p=0.003). In the edgeR analysis, the figure shows up- and down-regulated mRNA expression of 21 alterations (p values with FDR) potentially relevant to IBS-D: neurotransmitters [P2RY4 (p=0.001), VIP (p=0.02)]; ion channels [GUCA2B (p= 0.017), PDZD3 (p=0.029); cytokines [CCL20 (p=0.019)]; immune function [C4BPA complement cascade (p=0.0187)], TNFSF15 (p=0.0098), and IFIT3 (p=0.016)]; and mucosal repair and cell adhesion [TFF1 gastrointestinal trefoil protein (p= 0.012), RBP2 retinol binding protein (p=0.017), FN1 fibronectin (p=0.009), BIRC5 of inhibitor of apoptosis gene family (p=0.029)]. Ingenuity Pathway Analyses identified 76 categories of biological functions associated with the 21 genes: from non-specific cellular biochemical, energetics, and transport to specific GI function, growth, repair, and immune functions. Canonical Pathway Analysis identified 33 pathways (29 downregulated, 4 upregulated genes); the top 4 downregulated genes involved carbohydrate homeostasis and RBP2. Interferon signaling [IFIT3, MX1 (myxovirus resistance 1, interferon inducible), p<0.03] was the only pathway associated with upregulated genes. Conclusion: Rectosigmoid mucosa analysis by RNA-Seq in IBS-D shows transcriptome changes affecting neurotransmitters, ion channels, cytokines, immune function and cell adhesion that may reflect the pathobiology of IBS. Support: NIH DK92179 65 Fructose Consumption Impairs Serotonergic Signaling to the Submucous Plexus of Mouse Duodenum Katrien Lowette, Jan F. Tack, Pieter Vanden Berghe Since the development of high fructose corn syrup (HFCS) 50 years ago, the amount of fructose consumption in the western world has increased from 20 to 80 gram per day. Not only has fructose consumption been associated with an increased prevalence of the metabolic syndrome, recent studies also suggest a link with mild cognitive impairment. Regarding the fructose-induced consequences in neuronal processes, we aim to investigate the effects of fructose in the enteric nervous system of mice with a focus on serotonin signaling. Male C57/Bl6 mice were put on a 23% fructose drink diet for 4 weeks, controls received regular water. Drink and food consumption was measured daily, and body weight and serum glucose concentration was assessed weekly. Next, duodenal mRNA was extracted from total mucosa and isolated submucous plexus for RT-PCR. In addition, Ca2+-signaling (ΔF/F0) in duodenal submucous plexus neurons, loaded with Fluo-4, was measured in response to high K+ and 5-HT (10-5 M) stimulation. Mice on the fructose diet showed a significantly increased drink and a decreased food consumption compared to control mice. Body weight and serum glucose concentrations did not differ between groups. GLUT5 mRNA expression increased significantly after fructose consumption in duodenal mucosa (4.75±1.58 vs 36.24±6.04, p<0.01) and submucous plexus (1.38±0.51 vs 17.96±6.47, p<0.01). Fructose consumption resulted in decreased mRNA expression in total mucosa tissue of both synaptophysin (0.01±0.002 vs 0.005±0.0004, p<0.01) and synaptobrevin (0.17±0.03 vs 0.07±0.007, p<0.01) two important synaptic vesicle proteins as well as the serotonin receptor 5-HT3a (0.057±0.022 vs 0.006±0.003, p<0.05). Expression of the Ca2+ channels CaV2.1 (0.10±0.05 vs 0.03±0.003, p<0.05) and CaV2.2 (0.026±0.01 vs 0.007±0.0004, p<0.05) was significantly decreased after fructose consumption in total mucosa. In addition, the fructose-induced decrease of CaV2.2 (0.016±0.0064 vs 0.008±0.0004, p<0.05) was also present in the submu- cous plexus. Stimulation with high K+ (19±2 vs 18±2%) and 5-HT (5±0.4 vs 4±0.4%) did not induce significant differences in Ca2+-response amplitudes between both groups of mice. However, the number of high K+ responsive neurons per field of view (0.13 mm2) (13.35±1.33 vs 7.88±0.91, p<0.01) and the percentage of neurons identified by high K+ responding to 5-HT (54.5±8.67 vs 32.98±8.47%, p<0.05) was significantly decreased after fructose consumption. We conclude that excessive fructose consumption results in a down regulation of important components of the serotonergic signaling pathway to the submucous neurons of mouse duodenum, as well as a reduction in the number of neurons that can be depolarized and respond to serotonin.
Transcript of 62 Female Gender Favors Activation of Gut Immune and Barrier Regulatory Networks
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swere also used to evaluate their effect on Caco-2 paracellular permeability. RESULTS : IFN-γ mRNA expression was significantly higher in patients with IBS compared to HC (2-ΔΔCt=2.57±0.6 vs 2-ΔΔCt=0.66±0.1; P<0.05). In addition, we showed increased protein levels ofIFN-γ in biopsy homogenates of patients with IBS vs HC (increase of 48% in IBS-D;P<0.05).Similarly, we demonstrated a higher concentration of IFN-γ protein in IBS supernatants.The treatment of Caco-2 cells with IBS supernatants induced a significant decrease in SERTexpression compared to HC supernatants. IBS supernatants produced an increase in Caco-2 cell permeability. The effects of IBS supernatants on Caco-2 cells were mediated, at leastin part, by IFN-γ. CONCLUSIONS : We demonstrated an increased expression of IFN-γ inthe colonic mucosa of patients with IBS. We also showed increased IFN-γ amount both inbiopsies and supernatants of patients with IBS. Epithelial permeability was enhanced by IBSsupernatants which induced also a reduction of SERT expression, at least in part via IFN-γ. All together, these data suggest a potential role of IFN-γ in IBS pathophysiology.
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Female Gender Favors Activation of Gut Immune and Barrier RegulatoryNetworksCarmen Alonso, Marc Pigrau, María Vicario, Beatriz Lobo, Cristina Frias, Ana MaríaGonzález-Castro, Eloísa Salvo-Romero, Cesar Sevillano, Cristina Martinez, Bruno KotskaRodiño-Janeiro, Fernando Azpiroz, Javier Santos
INTRODUCTION: Irritable bowel syndrome (IBS) is a highly prevalent disorder, linked tointestinal epithelial dysfunction and mucosal microinflammation, with unexplained increasedwomen susceptibility. We have demonstrated that female gender per se determines intestinalbarrier dysfunction in response to acute experimental stress. This response could represent,in susceptible individuals, an early stage towards the onset of functional digestive diseases.AIMS&METHODS: We aim to identify gender-dependent molecular biomarkers of intestinalbarrier dysfunction in response to acute stress in healthy individuals to understand themechanistic origin of increased female prevalence in IBS. METHODS: Twelve men (M) and12 age-matched females (F) were recruited. In each participant, two consecutive jejunalbiopsies were obtained by Watson's capsule: one at baseline and another 90 min after 15min of intermittent cold pain stress (CPS). Throughout the study, autonomic (blood pressureand heart rate), hormonal (plasma cortisol) and psychological responses (Subjective StressRating Scale) to CPS were monitored. Mucosal RNA was isolated and submitted to microarrayanalysis followed by differential gene expression and biological pathways identification.RESULTS: CPS induced a significant autonomic response identified by increased heart rate,blood pressure and plasma cortisol, in association with elevated stress perception in allparticipants. Interestingly, gene expression studies uncovered differential responses to stressbetween M and F. Particularly, in the female group, CPS induced circadian rhythm regulation(P<0.00001), along with NK and T cell activation (NFIL3: 1.8; MAL: 1.8 fold change vsbasal), and changes in epithelial integrity proteins (KRT13: 1.9 fold change vs basal). In themale group, the stress response was associated with urea cycle and aminoacid metabolismactivation (P<0.005), and upregulation of antioxidant genes (SOD1: 1.9 fold change vs basal).CONCLUSION: Acute experimental stress highlights gender-specific molecular responsesinvolving immune activity and regulation of epithelial integrity in healthy gut, responsesthat may be linked to female predominance in IBS.
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Duodenal Acid Perfusion in Healthy Volunteers Results in Mast CellActivation and Increased PermeabilityHanne Vanheel, Tim Vanuytsel, María Vicario, Eveline Deloose, Jan F. Tack, Ricard Farré
Background: Functional dyspepsia (FD) is characterised by a variety of symptoms localisedin the epigastric region. We recently reported (Vanheel et al, Gut 2013) that patients withFD show impaired duodenal integrity, associated with low-grade inflammation. A potentialcause underlying impaired duodenal barrier function in FD may be the increased duodenalacid exposure that has been demonstrated in these patients (Lee et al, AJG 2004). Our aimwas to evaluate the effect of duodenal acid perfusion on duodenal integrity and immuneactivation in healthy volunteers. To assess activation of duodenogastric reflex pathways(Vanuytsel et al, NMO 2013), we also measured intragastric pressure (IGP). Methods: Tenhealthy volunteers (3 men; age 34.6±4.2 years) participated in the study. An infusion tubewas positioned in the second part of the duodenum and a high resolution manometry probewas positioned in the stomach to measure IGP. HCl 0.1 N or 0.9% saline was infused inthe duodenum during 30 min at a rate of 5 mL/min in a randomized, double-blind manner.Thirty minutes after infusion, endoscopic duodenal biopsy specimens were obtained tomeasure transepithelial electrical resistance and paracellular permeability for fluorescein-labeled dextrans (MW 4 kDa) in Ussing chambers. Expression of tight junction proteins inbiopsy specimens was evaluated at gene level by real-time RT-PCR (claudin 1-4, occludin,zonula occludens 1-3 and myosin light-chain kinase) and at protein level by western blot(claudin 1-4). Activation of mast cells and eosinophils was assessed by measuring tryptaseand eosinophilic major basic protein respectively, both at mRNA and protein level. Differencesbetween groups were analyzed using paired t tests or Wilcoxon signed rank tests whenappropriate. Results: Compared with saline infusion, acid perfusion significantly loweredtransepithelial electrical resistance (17.8±0.7 V.cm2 vs. 23.0±1.0 Ω.cm2, p=0.006) andincreased passage of fluorescein-labeled dextrans (57.4±7.5pmol vs. 31.8±4.6pmol, p=0.01)of duodenal biopsy specimens. No difference in gene expression of tight junction proteins,tryptase and eosinophilic major basic protein was detected. However, compared with salineinfusion, protein expression of claudin 3 was lower (0.55 fold; p=0.002) and tryptaseexpression was higher (1.86 fold; p=0.0008) after acid perfusion. In addition, IGP wassignificantly lower during acid perfusion compared with saline infusion (p=0.02). Conclu-sion: Duodenal acid perfusion in healthy volunteers disrupts epithelial integrity and activatesmucosal mast cells. This response could underlie altered permeability and low-grade inflam-mation observed in FD. Hence, increased duodenal acid exposure in patients with FD is apotential pathophysiological mechanism contributing to dyspeptic symptom generation.
S-18AGA Abstracts
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RNA Sequencing Shows Transcriptomic Changes in Rectosigmoid Mucosa inPatients With Irritable Bowel Syndrome-DiarrheaAndres Acosta, Paula Carlson, Irene A. Busciglio, Simon J. Gibbons, Gianrico Farrugia,Eric W. Klee, Michael Camilleri
Background: Changes in mucosal biology in patients with IBS-diarrhea (IBS-D) includeimmune activation, barrier dysfunction and increased fluid secretion. The underlying mecha-nisms are unclear. Aim: To compare expression of mRNA in rectosigmoid mucosa from 9female IBS-D patients [with accelerated colonic transit (CT)] and 9 female healthy controls(with normal CT), and identify other biologically relevant transcriptome changes. Method:We used stored samples from 9 patients with rapid CT (geometric center, GC24: 4.19-4.92)and 9 controls with normal CT (GC24: 1.15-2.63). RNA was sequenced (RNA-Seq) onIllumina HiSeq 2000 using TruSeq SBS Sequencing Kit Version 3. Analysis of each sample[alignment statistics, in-depth quality control metrics, gene and exon expression levels,fusion transcripts and single nucleotide variants (SNVs)] was done using Mayo Clinic's MAPRSeq v1.0, a computational workflow for analysis of RNA-Seq. Gene expression variation wasexamined by edgeR in the following "targeted" genes associated with IBS in the literature:5-HTTLPR, TNFSF15, FAAH, CNR1, KLB, FGFR4, GPBAR1, TLR9, C11orf30, ORMDL3,NPSR1, and HLA 2/8. Associations of IBS-D with any other gene mRNA was compared tocontrol expression by edgeR, independent of any a priori hypothesis. Ingenuity and CanonicalPathway Analyses were conducted on mRNA of 21 genes significant after FDR (p=0.034).Results: Of the 12 "targeted" genes tested, patients with IBS-D had increased mRNA expres-sion of TNFSF15 (fold change 1.53, p=0.003). In the edgeR analysis, the figure shows up-and down-regulated mRNA expression of 21 alterations (p values with FDR) potentiallyrelevant to IBS-D: neurotransmitters [P2RY4 (p=0.001), VIP (p=0.02)]; ion channels[GUCA2B (p= 0.017), PDZD3 (p=0.029); cytokines [CCL20 (p=0.019)]; immune function[C4BPA complement cascade (p=0.0187)], TNFSF15 (p=0.0098), and IFIT3 (p=0.016)];and mucosal repair and cell adhesion [TFF1 gastrointestinal trefoil protein (p= 0.012),RBP2 retinol binding protein (p=0.017), FN1 fibronectin (p=0.009), BIRC5 of inhibitor ofapoptosis gene family (p=0.029)]. Ingenuity Pathway Analyses identified 76 categories ofbiological functions associated with the 21 genes: from non-specific cellular biochemical,energetics, and transport to specific GI function, growth, repair, and immune functions.Canonical Pathway Analysis identified 33 pathways (29 downregulated, 4 upregulated genes);the top 4 downregulated genes involved carbohydrate homeostasis and RBP2. Interferonsignaling [IFIT3, MX1 (myxovirus resistance 1, interferon inducible), p<0.03] was the onlypathway associated with upregulated genes. Conclusion: Rectosigmoid mucosa analysis byRNA-Seq in IBS-D shows transcriptome changes affecting neurotransmitters, ion channels,cytokines, immune function and cell adhesion that may reflect the pathobiology of IBS.Support: NIH DK92179
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Fructose Consumption Impairs Serotonergic Signaling to the SubmucousPlexus of Mouse DuodenumKatrien Lowette, Jan F. Tack, Pieter Vanden Berghe
Since the development of high fructose corn syrup (HFCS) 50 years ago, the amount offructose consumption in the western world has increased from 20 to 80 gram per day. Notonly has fructose consumption been associated with an increased prevalence of the metabolicsyndrome, recent studies also suggest a link with mild cognitive impairment. Regarding thefructose-induced consequences in neuronal processes, we aim to investigate the effects offructose in the enteric nervous system of mice with a focus on serotonin signaling. MaleC57/Bl6 mice were put on a 23% fructose drink diet for 4 weeks, controls received regularwater. Drink and food consumption was measured daily, and body weight and serum glucoseconcentration was assessed weekly. Next, duodenal mRNA was extracted from total mucosaand isolated submucous plexus for RT-PCR. In addition, Ca2+-signaling (ΔF/F0) in duodenalsubmucous plexus neurons, loaded with Fluo-4, was measured in response to high K+ and5-HT (10-5 M) stimulation. Mice on the fructose diet showed a significantly increased drinkand a decreased food consumption compared to control mice. Body weight and serumglucose concentrations did not differ between groups. GLUT5 mRNA expression increasedsignificantly after fructose consumption in duodenal mucosa (4.75±1.58 vs 36.24±6.04,p<0.01) and submucous plexus (1.38±0.51 vs 17.96±6.47, p<0.01). Fructose consumptionresulted in decreased mRNA expression in total mucosa tissue of both synaptophysin(0.01±0.002 vs 0.005±0.0004, p<0.01) and synaptobrevin (0.17±0.03 vs 0.07±0.007,p<0.01) two important synaptic vesicle proteins as well as the serotonin receptor 5-HT3a(0.057±0.022 vs 0.006±0.003, p<0.05). Expression of the Ca2+ channels CaV2.1 (0.10±0.05vs 0.03±0.003, p<0.05) and CaV2.2 (0.026±0.01 vs 0.007±0.0004, p<0.05) was significantlydecreased after fructose consumption in total mucosa. In addition, the fructose-induceddecrease of CaV2.2 (0.016±0.0064 vs 0.008±0.0004, p<0.05) was also present in the submu-cous plexus. Stimulation with high K+ (19±2 vs 18±2%) and 5-HT (5±0.4 vs 4±0.4%) didnot induce significant differences in Ca2+-response amplitudes between both groups ofmice. However, the number of high K+ responsive neurons per field of view (0.13 mm2)(13.35±1.33 vs 7.88±0.91, p<0.01) and the percentage of neurons identified by high K+responding to 5-HT (54.5±8.67 vs 32.98±8.47%, p<0.05) was significantly decreased afterfructose consumption. We conclude that excessive fructose consumption results in a downregulation of important components of the serotonergic signaling pathway to the submucousneurons of mouse duodenum, as well as a reduction in the number of neurons that can bedepolarized and respond to serotonin.
