Calcimimetic R568 inhibits tetrodotoxin-sensitive colonic electrolyte secretion and reduces c-fos expression in myenteric neurons

Serotonin [5-hydroxytryptamine (5-HT)] acts as a modulator of colonic motility and secretion. We characterized the action of the 5-HT precursor 5-hydroxytryptophan (5-HTP) on colonic myenteric neurons and propulsive motor activity in conscious mice. Fos immunoreactivity (IR), used as a marker of neuronal activation, was monitored in longitudinal muscle/myenteric plexus whole mount preparations of the distal colon 90 min after an intraperitoneal injection of 5-HTP. Double staining of Fos IR with peripheral choline acetyltransferase (pChAT) IR or NADPH-diaphorase activity was performed. The injection of 5-HTP (0.5, 1, 5, or 10 mg/kg ip) increased fecal pellet output and fluid content in a dose-related manner, with a peak response observed within the first 15 min postinjection. 5-HTP (0.5–10 mg/kg) dose dependently increased Fos expression in myenteric neurons, with a maximal response of 9.9 ± 1.0 cells/ganglion [ P < 0.05 vs. vehicle-treated mice (2.3 ± 0.6 cells/ganglion)]. There was a positive correlation between Fos expression and fecal output. Of Fos-positive ganglionic cells, 40 ± 4% were also pChAT positive and 21 ± 5% were NADPH-diaphorase positive in response to 5-HTP, respectively. 5-HTP-induced defecation and Fos expression were completely prevented by pretreatment with the selective 5-HT4 antagonist RS-39604. These results show that 5-HTP injected peripherally increases Fos expression in different populations of cholinergic and nitrergic myenteric neurons in the distal colon and stimulates propulsive colonic motor function through 5-HT4 receptors in conscious mice. These findings suggest an important role of activation of colonic myenteric neurons in the 5-HT4 receptor-mediated colonic propulsive motor response.

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Peripheral corticotropin-releasing factor (CRF) stimulates fos expression in the rat colonic myenteric neurons andfecal pellet output through CRF receptor subtype 1

Gastroenterology ◽

10.1016/s0016-5085(00)84692-2 ◽

2000 ◽

Vol 118 (4) ◽

pp. A638 ◽

Cited By ~ 1

Author(s):

Marcel Miampamba ◽

Celine Maillot ◽

Mulugeta Million ◽

Yvette Tache

Keyword(s):

Corticotropin Releasing Factor ◽

Receptor Subtype ◽

Myenteric Neurons ◽

Fos Expression

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VIP is involved in peripheral CRF-induced stimulation of propulsive colonic motor function and diarrhea in male rats

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00308.2017 ◽

2018 ◽

Vol 314 (5) ◽

pp. G610-G622 ◽

Cited By ~ 2

Author(s):

Seiichi Yakabi ◽

Lixin Wang ◽

Hiroshi Karasawa ◽

Pu-Qing Yuan ◽

Kazuhiko Koike ◽

...

Keyword(s):

Vasoactive Intestinal Peptide ◽

Motor Function ◽

Terminal Ileum ◽

Proximal Colon ◽

Corticotropin Releasing Factor ◽

Submucosal Plexus ◽

Myenteric Neurons ◽

Colonic Motor ◽

Fos Expression ◽

Stimulation Of

We investigated whether vasoactive intestinal peptide (VIP) and/or prostaglandins contribute to peripheral corticotropin-releasing factor (CRF)-induced CRF1 receptor-mediated stimulation of colonic motor function and diarrhea in rats. The VIP antagonist, [4Cl-D-Phe6, Leu17]VIP injected intraperitoneally completely prevented CRF (10 µg/kg ip)-induced fecal output and diarrhea occurring within the first hour after injection, whereas pretreatment with the prostaglandins synthesis inhibitor, indomethacin, had no effect. In submucosal plexus neurons, CRF induced significant c-Fos expression most prominently in the terminal ileum compared with duodenum and jejunum, whereas no c-Fos was observed in the proximal colon. c-Fos expression in ileal submucosa was colocalized in 93.4% of VIP-positive neurons and 31.1% of non-VIP-labeled neurons. CRF1 receptor immunoreactivity was found on the VIP neurons. In myenteric neurons, CRF induced only a few c-Fos-positive neurons in the ileum and a robust expression in the proximal colon (17.5 ± 2.4 vs. 0.4 ± 0.3 cells/ganglion in vehicle). The VIP antagonist prevented intraperitoneal CRF-induced c-Fos induction in the ileal submucosal plexus and proximal colon myenteric plexus. At 60 min after injection, CRF decreased VIP levels in the terminal ileum compared with saline (0.8 ± 0.3 vs. 2.5 ± 0.7 ng/g), whereas VIP mRNA level detected by qPCR was not changed. These data indicate that intraperitoneal CRF activates intestinal submucosal VIP neurons most prominently in the ileum and myenteric neurons in the colon. It also implicates VIP signaling as part of underlying mechanisms driving the acute colonic secretomotor response to a peripheral injection of CRF, whereas prostaglandins do not play a role. NEW & NOTEWORTHY Corticotropin-releasing factor (CRF) in the gut plays a physiological role in the stimulation of lower gut secretomotor function induced by stress. We showed that vasoactive intestinal peptide (VIP)-immunoreactive neurons in the ileal submucosal plexus expressed CRF1 receptor and were prominently activated by CRF, unlike colonic submucosal neurons. VIP antagonist abrogated CRF-induced ileal submucosal and colonic myenteric activation along with functional responses (defecation and diarrhea). These data point to VIP signaling in ileum and colon as downstream effectors of CRF.

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CCK-A receptor activation induces Fos expression in myenteric neurons of rat small intestine

Regulatory Peptides ◽

10.1016/s0167-0115(99)00124-x ◽

2000 ◽

Vol 88 (1-3) ◽

pp. 75-81 ◽

Cited By ~ 42

Author(s):

Ayman I Sayegh ◽

Robert C Ritter

Keyword(s):

Small Intestine ◽

Receptor Activation ◽

Rat Small Intestine ◽

Myenteric Neurons ◽

Fos Expression

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Intracisternal TRH analog induces Fos expression in gastric myenteric neurons and glia in conscious rats

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.2001.280.5.g979 ◽

2001 ◽

Vol 280 (5) ◽

pp. G979-G991 ◽

Cited By ~ 28

Author(s):

Marcel Miampamba ◽

Hong Yang ◽

Keith A. Sharkey ◽

Yvette Taché

Keyword(s):

Protein Gene ◽

Longitudinal Muscle ◽

Neuronal Marker ◽

Myenteric Neurons ◽

Conscious Rats ◽

Protein Gene Product ◽

Intracisternal Injection ◽

S 100 ◽

Acidic Proteins ◽

Fos Expression

Activation of gastric myenteric cells by intracisternal injection of the stable thyrotropin-releasing hormone (TRH) analog RX-77368, at a dose inducing near maximal vagal cholinergic stimulation of gastric functions, was investigated in conscious rats. Fos immunoreactivity was assessed in gastric longitudinal muscle-myenteric plexus whole mount preparations 90 min after intracisternal injection. Fos-immunoreactive cells were rare in controls (∼1 cell/ganglion), whereas intracisternal RX-77368 (50 ng) increased the number to 24.8 ± 1.8 and 26.8 ± 2.2 cells/ganglion in the corpus and antrum, respectively. Hexamethonium (20 mg/kg sc) prevented Fos expression by 90%, whereas atropine (2 mg/kg sc) had no effect. The neuronal marker protein gene product 9.5 and the glial markers S-100 and glial fibrillary acidic proteins showed that RX-77368 induced Fos in both myenteric neurons and glia. Vesicular ACh transporter and calretinin were detected around the activated myenteric neurons. These results indicated that central vagal efferent stimulation by intracisternal RX-77368 activates gastric myenteric neurons as well as glial cells mainly through nicotinic ACh receptors in conscious rats.

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Acute cold exposure induces vagally mediated Fos expression in gastric myenteric neurons in conscious rats

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.2001.281.2.g560 ◽

2001 ◽

Vol 281 (2) ◽

pp. G560-G568 ◽

Cited By ~ 8

Author(s):

Pu-Qing Yuan ◽

Yvette Taché ◽

Marcel Miampamba ◽

Hong Yang

Keyword(s):

Cold Exposure ◽

Room Temperature ◽

Double Labeling ◽

Myenteric Neurons ◽

Conscious Rats ◽

Acute Cold Exposure ◽

Cervical Vagotomy ◽

Fos Expression ◽

Fasted Rats ◽

Myenteric Ganglia

Acute cold exposure-induced activation of gastric myenteric neurons in conscious rats was examined on longitudinal muscle-myenteric plexus whole mount preparations. Few Fos-immunoreactive (IR) cells (<1/ganglion) were observed in 24-h fasted rats semirestrained at room temperature. Cold exposure (4°C) for 1–3 h induced a time-related increase of Fos-IR cells in corpus and antral myenteric ganglia with a maximal plateau response (17 ± 3 and 18 ± 3 cells/ganglion, respectively) occurring at 2 h. Gastric vagotomy partly prevented, whereas bilateral cervical vagotomy completely abolished, Fos expression in the myenteric cells induced by cold exposure (2 h). Hexamethonium (20 mg/kg) also prevented 3-h cold exposure-induced myenteric Fos expression by 76–80%, whereas atropine or bretylium had no effect. Double labeling revealed that cold (3 h)-induced Fos-IR myenteric cells were mainly neurons, including a substantial number of choline acetyltransferase-containing neurons and most NADPH-diaphorase-positive neurons. These results indicate that acute cold exposure activates cholinergic as well as nitrergic neurons in the gastric myenteric ganglia through vagal nicotinic pathways in conscious rats.

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