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ABSTRACT: To assess corticotropin-releasing factor receptor 2 (CRF2) expression in the colon of healthy subjects and patients with ulcerative colitis (UC).
We examined CRF2 gene and protein expression in the distal/sigmoid colonic mucosal biopsies from healthy subjects and patients with UC (active or disease in remission), human immunodeficiency virus (HIV) and functional bowel disease (FBD) by reverse transcription-polymerase chain reaction and immunofluorescence.
Gene expression of CRF2 was demonstrated in the normal human colonic biopsies, but not in the human colorectal adenocarcinoma cell line Caco2. Receptor protein localization showed immunoreactive CRF2 receptors in the lamina propria and in the epithelial cells of the distal/sigmoid biopsy samples. Interestingly, CRF2 immunoreactivity was no longer observed in epithelial cells of patients with mild-moderately active UC and disease in remission, while receptor protein expression did not change in the lamina propria. No differences in CRF2 expression profile were observed in distal/sigmoid intestinal biopsies from HIV infection and FBD patients, showing no signs of inflammation.
The down-regulation of the CRF2 receptor in the distal/sigmoid biopsies of UC patients is indicative of change in CRF2 signalling associated with the process of inflammation.
World Journal of Gastroenterology 03/2013; 19(9):1416-23. · 2.47 Impact Factor
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ABSTRACT: Brain corticotropin-releasing factor (CRF) acting on CRF receptor type 1 (CRF(1)) is a main signaling pathway in the stress response. CRF is also produced in a variety of peripheral sites and acts locally as a proinflammatory mediator. We investigated CRF(1) mRNA expression in the human gastrointestinal tract, and localized CRF(1) immunoreactive cells in the colonic mucosa of healthy subjects and patients with ulcerative colitis (UC). In 4 male healthy subjects (24-29 years), CRF(1) transcript was detected by RT-PCR throughout the gastrointestinal tract with the highest levels in the ileum and rectum and the lowest level in the colon. Immunohistochemistry on whole thickness sigmoid colon sections showed that CRF(1) was localized in the lamina propria and epithelial cells and enteric neurons. In sigmoid colonic biopsies, immunohistochemically double-labeled cells with CRF(1) and CD163, a marker for macrophages, represent 79% of total CRF(1) immunoreactive (IR) cells in healthy subjects. In 10 UC patients, the total number of CRF(1) IR cells and CRF(1)/CD163 double-labeled macrophages was increased by 4.2 and 4.0 folds respectively compared to healthy subjects. These findings indicate that CRF(1) is distributed throughout the GI tract of healthy human subjects. The increase of CRF(1) IR cells prominently in macrophages of the sigmoid colonic mucosa of UC patients provides anatomical support for a role of CRF(1) signaling in modulating the immune-inflammatory process of UC.
Peptides 08/2012; 38(1):62-69. · 2.43 Impact Factor
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ABSTRACT: We previously showed that medullary thyrotropin-releasing hormone (TRH) or the stable TRH agonist, RX-77368 administered intracisternally induces vagal-dependent activation of gastric myenteric neurons and prevents post surgery-induced delayed gastric emptying in rats. We investigated whether abdominal surgery alters intracisternal (ic) RX-77368 (50 ng)-induced gastric myenteric neuron activation. Under 10 min enflurane anesthesia, rats underwent an ic injection of saline or RX-77368 followed by a laparotomy and a 1-min cecal palpation, or no surgery and were euthanized 90 min later. Longitudinal muscle/myenteric plexus whole-mount preparations of gastric corpus and antrum were processed for immunohistochemical detection of Fos alone or double labeled with protein gene-product 9.5 (PGP 9.5) and vesicular acetylcholine transporter (VAChT). In the non surgery groups, ic RX-77368 induced a 17 fold increase in Fos-expression in both gastric antrum and corpus myenteric neurons compared to saline injected rats. PGP 9.5 ascertained the neuronal identity of myenteric cells expressing Fos. In the abdominal surgery groups, ic RX-77368 induced a significant increase in Fos-expression in both the corpus and antrum myenteric ganglia compared with ic saline injected rats which has no Fos in the gastric myenteric ganglia. However, the response was reduced by 73-78% compared with that induced by ic RX 77368 without surgery. Abundant VAChT positive nerve fibers were present around Fos positive neurons. These results indicate a bidirectional interaction between central vagal stimulation of gastric myenteric neurons and abdominal surgery. The modulation of gastric vagus-myenteric neuron activity could play an important role in the recovery phase of postoperative gastric ileus.
Peptides 03/2011; 32(5):1078-82. · 2.43 Impact Factor
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ABSTRACT: Acute in vivo measurements are often the initial, most practicable approach used to investigate the effects of novel compounds or genetic manipulations on the regulation of gastric motility. Such acute methods typically involve either surgical implantation of devices or require intragastric perfusion of solutions, which can substantially alter gastric activity and may require extended periods of time to allow stabilization or recovery of the preparation. We validated a simple, non-invasive novel method to measure acutely gastric contractility, using a solid-state catheter pressure transducer inserted orally into the gastric corpus, in fasted, anesthetized rats or mice. The area under the curve of the phasic component (pAUC) of intragastric pressure (IGP) was obtained from continuous manometric recordings of basal activity and in responses to central or peripheral activation of cholinergic pathways, or to abdominal surgery. In rats, intravenous ghrelin or intracisternal injection of the thyrotropin-releasing hormone agonist, RX-77368, significantly increased pAUC while coeliotomy and cacal palpation induced a rapid onset inhibition of phasic activity lasting for the 1-h recording period. In mice, RX-77368 injected into the lateral brain ventricle induced high-amplitude contractions, and carbachol injected intraperitoneally increased pAUC significantly, while coeliotomy and cecal palpation inhibited baseline contractile activity. In wild-type mice, cold exposure (15 min) increased gastric phasic activity and tone, while there was no gastric response in corticotropin releasing factor (CRF)-overexpressing mice, a model of chronic stress. Thus, the novel solid-state manometric approach provides a simple, reliable means for acute pharmacological studies of gastric motility effects in rodents. Using this method we established in mice that the gastric motility response to central vagal activation is impaired under chronic expression of CRF.
Peptides 01/2011; 32(4):737-46. · 2.43 Impact Factor
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ABSTRACT: Corticotropin-releasing factor (CRF) signaling pathways are involved in the stress response, and there is growing evidence supporting hair growth inhibition of murine hair follicle in vivo upon stress exposure. We investigated whether the blockade of CRF receptors influences the development of hair loss in CRF over-expressing (OE)-mice that display phenotypes of Cushing's syndrome and chronic stress, including alopecia. The non-selective CRF receptors antagonist, astressin-B (5 µg/mouse) injected peripherally once a day for 5 days in 4-9 months old CRF-OE alopecic mice induced pigmentation and hair re-growth that was largely retained for over 4 months. In young CRF-OE mice, astressin-B prevented the development of alopecia that occurred in saline-treated mice. Histological examination indicated that alopecic CRF-OE mice had hair follicle atrophy and that astressin-B revived the hair follicle from the telogen to anagen phase. However, astressin-B did not show any effect on the elevated plasma corticosterone levels and the increased weights of adrenal glands and visceral fat in CRF-OE mice. The selective CRF₂ receptor antagonist, astressin₂-B had moderate effect on pigmentation, but not on hair re-growth. The commercial drug for alopecia, minoxidil only showed partial effect on hair re-growth. These data support the existence of a key molecular switching mechanism triggered by blocking peripheral CRF receptors with an antagonist to reset hair growth in a mouse model of alopecia associated with chronic stress.
PLoS ONE 01/2011; 6(2):e16377. · 4.09 Impact Factor
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Guillaume Gourcerol,
S Vincent Wu,
Pu-Qing Yuan,
Hung Pham,
Marcel Miampamba,
Muriel Larauche,
Paul Sanders,
Tomofumi Amano,
Agata Mulak,
Eunok Im,
Charalabos Pothoulakis,
Jean Rivier,
Yvette Taché, Mulugeta Million
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ABSTRACT: Corticotropin-releasing factor receptor-1 (CRF(1)) mediates the stress-induced colonic motor activity. Less is known about the role of CRF(2) in the colonic response to stress.
We studied colonic contractile activity in rats and CRF(2)-/-, CRF-overexpressing, and wild-type mice using still manometry; we analyzed defecation induced by acute partial-restraint stress (PRS), and/or intraperitoneal injection of CRF ligands. In rats, we monitored activation of the colonic longitudinal muscle myenteric plexus (LMMP) neurons and localization of CRF(1) and CRF(2) using immunohistochemical and immunoblot analyses. We measured phosphorylation of extracellular signal-regulated kinase 1/2 by CRF ligands in primary cultures of LMMP neurons (PC-LMMPn) and cyclic adenosine monophosphate (cAMP) production in human embryonic kidney-293 cells transfected with CRF(1) and/or CRF(2).
In rats, a selective agonist of CRF(2) (urocortin 2) reduced CRF-induced defecation (>50%), colonic contractile activity, and Fos expression in the colonic LMMP. A selective antagonist of CRF(2) (astressin(2)-B) increased these responses. Urocortin 2 reduced PRS-induced colonic contractile activity in wild-type and CRF-overexpressing mice, whereas disruption of CRF(2) increased PRS-induced colonic contractile activity and CRF-induced defecation. CRF(2) colocalized with CRF(1) and neuronal nitric oxide synthase in the rat colon, LMMP, and PC-LMMPn. CRF-induced phosphorylation of extracellular signal-regulated kinase in PC-LMMPn; this was inhibited or increased by a selective antagonist of CRF(1) (NBI35965) or astressin(2)-B, respectively. The half maximal effective concentration, EC(50), for the CRF-induced cAMP response was 8.6 nmol/L in human embryonic kidney-293 cells that express only CRF(1); this response was suppressed 10-fold in cells that express CRF(1) and CRF(2).
In colon tissues of rodents, CRF(2) activation inhibits CRF(1) signaling in myenteric neurons and the stress-induced colonic motor responses. Disruption of CRF(2) function impairs colonic coping responses to stress.
Gastroenterology 01/2011; 140(5):1586-96.e6. · 11.68 Impact Factor
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ABSTRACT: Visceral pain modulation by chronic stress in mice has been little studied. Electromyography (EMG) recording of abdominal muscle contractions, as a proxy to the visceromotor response (VMR), requires electrode implantation and post-surgical single housing (SH) which could affect the VMR to stress. To test this hypothesis, male mice had electrode implantation surgery (S) plus SH, or no surgery and were group housed (NS-GH) or single housed (NS-SH) and exposed to either water avoidance stress (WAS, 1 h/day) or left undisturbed in their home cages for 10 days. The VMR to phasic ascending colorectal distension (CRD) was assessed before (basal) and 24 h after 10 days of WAS or no stress using a surgery-free method of intraluminal colonic pressure (ICP) recording (solid-state manometry). WAS heightened significantly the VMR to CRD at 30, 45, and 60 mmHg in S-SH vs. NS-GH, but not compared to NS-SH conscious mice. Compared to basal CRD, WAS increased VMR at 60 mmHg in the S-SH group and decreased it at 30-60 mmHg in NS-GH mice, while having no effect in NS-SH mice. The average defecation during the hour of repeated WAS over 10 days was 1.9 and 2.4 fold greater in S-SH vs. NS-GH and NS-SH mice, respectively. These data indicate that the combination of S-SH required for VMR monitoring with EMG is an important component of repeated WAS-induced post-stress visceral hypersensitivity and defecation in mice.
Stress (Amsterdam, Netherlands) 07/2010; 13(4):343-54. · 3.21 Impact Factor
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ABSTRACT: Chronic stress and persistently high glucocorticoid levels can induce brain atrophy. Corticotropin-releasing factor (CRF)-overexpressing (OE) mice are a genetic model of chronic stress with elevated brain CRF and plasma corticosterone levels and Cushing's syndrome. The brain structural alterations in the CRF-OE mice, however, are not well known. We found that adult male and female CRF-OE mice had significantly lower whole brain and cerebellum weights than their wild type (WT) littermates (347.7+/-3.6mg vs. 460.1+/-4.3mg and 36.3+/-0.8mg vs. 50.0+/-1.3mg, respectively) without sex-related difference. The epididymal/parametrial fat mass was significantly higher in CRF-OE mice. The brain weight was inversely correlated to epididymal/parametrial fat weight, but not to body weight. Computerized image analysis system in Nissl-stained brain sections of female mice showed that the anterior cingulate and sensorimotor cortexes of CRF-OE mice were significantly thinner, and the volumes of the hippocampus, hypothalamic paraventricular nucleus and amygdala were significantly reduced compared to WT, while the locus coeruleus showed a non-significant increase. Motor functions determined by beam crossing and gait analysis showed that CRF-OE mice took longer time and more steps to traverse a beam with more errors, and displayed reduced stride length compared to their WT littermates. These data show that CRF-OE mice display brain size reduction associated with alterations of motor coordination and an increase in visceral fat mass providing a novel animal model to study mechanisms involved in brain atrophy under conditions of sustained elevation of brain CRF and circulating glucocorticoid levels.
Neuroscience Letters 03/2010; 473(1):11-5. · 2.11 Impact Factor
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ABSTRACT: Peptide YY (PYY) antisecretory effect on intestinal epithelia is well established, whereas less is known about its actions to influence colonic motility in conscious animals. We characterized changes in basal function and stimulated colonic motor function induced by PYY-related peptides in conscious mice. PYY(3-36), PYY, and neuropeptide Y (NPY) (8 nmol/kg) injected intraperitoneally inhibited fecal pellet output (FPO) per hour during novel environment stress by 90%, 63%, and 57%, respectively, whereas the Y(1)-preferring agonists, [Pro(34)]PYY and [Leu(31),Pro(34)]NPY, had no effect. Corticotrophin-releasing factor 2 receptor antagonist did not alter PYY(3-36) inhibitory action. PYY and PYY(3-36) significantly reduced restraint-stimulated defecation, and PYY(3-36) inhibited high-amplitude distal colonic contractions in restrained conscious mice for 1 h, by intraluminal pressure with the use of a microtransducer. PYY suppression of intraperitoneal 5-hydroxytryptophan induced FPO and diarrhea was blocked by the Y(2) antagonist, BIIE0246, injected intraperitoneally and mimicked by PYY(3-36), but not [Leu(31),Pro(34)]NPY. PYY(3-36) also inhibited bethanechol-stimulated FPO and diarrhea. PYY(3-36) inhibited basal FPO during nocturnal feeding period and light phase in fasted/refed mice for 2-3 h, whereas the reduction of food intake lasted for only 1 h. PYY(3-36) delayed gastric emptying after fasting-refeeding by 48% and distal colonic transit time by 104%, whereas [Leu(31),Pro(34)]NPY had no effect. In the proximal and distal colon, higher Y(2) mRNA expression was detected in the mucosa than in muscle layers, and Y(2) immunoreactivity was located in nerve terminals around myenteric neurons. These data established that PYY/PYY(3-36) potently inhibits basal and stress/serotonin/cholinergic-stimulated propulsive colonic motor function in conscious mice, likely via Y(2) receptors.
AJP Gastrointestinal and Liver Physiology 11/2009; 298(1):G45-56. · 3.43 Impact Factor
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ABSTRACT: Corticotropin-releasing factor (CRF) 1 receptor (CRF(1)) activation in the brain is a core pathway orchestrating the stress response. Anatomical data also support the existence of CRF signaling components within the colon. We investigated the colonic response to intraperitoneal (ip) injection of cortagine, a newly developed selective CRF(1) peptide agonist. Colonic motor function and visceral motor response (VMR) were monitored by using a modified miniaturized pressure transducer catheter in adult conscious male Sprague-Dawley rats and C57Bl/6 mice. Colonic permeability was monitored by the Evans blue method and myenteric neurons activation by Fos immunohistochemistry. Compared with vehicle, cortagine (10 microg/kg ip) significantly decreased the distal colonic transit time by 45% without affecting gastric transit, increased distal and transverse colonic contractility by 35.6 and 66.2%, respectively, and induced a 7.1-fold increase in defecation and watery diarrhea in 50% of rats during the first hour postinjection whereas intracerebroventricular (icv) cortagine (3 microg/rat) had lesser effects. Intraperitoneal (ip) cortagine also increased colonic permeability, activated proximal and distal colonic myenteric neurons, and induced visceral hypersensitivity to a second set of phasic colorectal distention (CRD). The CRF antagonist astressin (10 mug/kg ip) abolished ip cortagine-induced hyperalgesia whereas injected icv it had no effect. In mice, cortagine (30 microg/kg ip) stimulated defecation by 7.8-fold, induced 60% incidence of diarrhea, and increased VMR to CRD. Stresslike colonic alterations induced by ip cortagine in rats and mice through restricted activation of peripheral CRF(1) receptors support a role for peripheral CRF(1) signaling as the local arm of the colonic response to stress.
AJP Gastrointestinal and Liver Physiology 05/2009; 297(1):G215-27. · 3.43 Impact Factor
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ABSTRACT: There is a glaring lack of knowledge on mouse colonic motility in vivo, primarily due to unavailability of adequate recording methods. Using a noninvasive miniature catheter pressure transducer inserted into the distal colon, we assessed changes in colonic motility in conscious mice induced by various acute or chronic stressors and determined the neurotransmitters mediating these changes. Mice exposed to restraint stress (RS) for 60 min displayed distal colonic phasic contractions including high-amplitude giant migrating contractions (GMCs), which had peak amplitudes >25 mmHg and occurred at a rate of 15-25 h(-1) of which over 50% were aborally propagative. Responses during the first 20-min of RS were characterized by high-frequency and high-amplitude contractions that were correlated with defecation. RS-induced GMCs and fecal pellet output were blocked by atropine (0.5 mg/kg ip) or the corticotrophin releasing factor (CRF) receptor antagonist astressin-B (100 microg/kg ip). RS activated colonic myenteric neurons as shown by Fos immunoreactivity. In mice previously exposed to repeated RS (60 min/day, 14 days), or in transgenic mice that overexpress CRF, the duration of stimulation of phasic colonic contractions was significantly shorter (10 vs. 20 min). In contrast to RS, abdominal surgery abolished colonic contractions including GMCs. These findings provide the first evidence for the presence of frequent cholinergic-dependent GMCs in the distal colon of conscious mice and their modulation by acute and chronic stressors. Noninvasive colonic manometry opens new venues to investigate colonic motor function in genetically modified mice relevant to diseases that involve colonic motility alterations.
AJP Gastrointestinal and Liver Physiology 03/2009; 296(5):G992-G1002. · 3.43 Impact Factor
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ABSTRACT: Corticotropin-releasing factor (CRF) overexpressing (OE) mice are a genetic model that exhibits features of chronic stress. We investigated whether the adaptive feeding response to a hypocaloric challenge induced by food deprivation is impaired under conditions of chronic CRF overproduction. Food intake response to a 16-h overnight fast and ip injection of gut hormones regulating food intake were compared in CRF-OE and wild type (WT) littermate mice along with brain Fos expression, circulating ghrelin levels, and gastric emptying of a nonnutrient meal. CRF-OE mice injected ip with saline showed a 47 and 44% reduction of 30-min and 4-h cumulative food intake response to an overnight fast, respectively, compared with WT. However, the 30-min food intake decrease induced by ip cholecystokinin (3 microg/kg) and increase by ghrelin (300 microg/kg) were similar in CRF-OE and WT mice. Overnight fasting increased the plasma total ghrelin to similar levels in CRF-OE and WT mice, although CRF-OE mice had a 2-fold reduction of nonfasting ghrelin levels. The number of Fos-immunoreactive cells induced by fasting in the arcuate nucleus was reduced by 5.9-fold in CRF-OE compared with WT mice whereas no significant changes were observed in other hypothalamic nuclei. In contrast, fasted CRF-OE mice displayed a 5.6-fold increase in Fos-immunoreactive cell number in the dorsal motor nucleus of the vagus nerve and a 34% increase in 20-min gastric emptying. These findings indicate that sustained overproduction of hypothalamic CRF in mice interferes with fasting-induced activation of arcuate nucleus neurons and the related hyperphagic response.
Endocrinology 10/2008; 150(1):153-60. · 4.46 Impact Factor
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ABSTRACT: Visceral hypersensitivity has been implicated as an important pathophysiological mechanism in functional gastrointestinal disorders. In this study, we investigated whether the sustained visceral hyperalgesia induced by repeated psychological stress in rats involves the activation of CRF(1) signaling system using two different antagonists. Male Wistar rats were exposed to 10 consecutive days of water avoidance stress (WAS) or sham stress for 1 h/day, and the visceromotor response to phasic colorectal distension (CRD) was assessed before and after the stress period. Animals were injected subcutaneously with the brain penetrant CRF(1) antagonist, CP-154,526, acutely (30 min before the final CRD) or chronically (via osmotic minipump implanted subcutaneously, during stress) or with the peripherally restricted, nonselective CRF(1) and CRF(2) antagonist, astressin, chronically (15 min before each stress session). Repeated WAS induced visceral hypersensitivity to CRD at 40 and 60 mmHg. CP-154,526 injected acutely significantly reduced stress-induced visceral hyperalgesia at 40 mmHg but not at 60 mmHg. Chronic subcutaneous delivery of astressin reduced the stress-induced visceral hyperalgesia to baseline at all distension pressures. Interestingly, chronically administered CP-154,526 eliminated hyperalgesia and produced responses below baseline at 40 mmHg and 60 mmHg, indicating a hypoalgesic effect of the compound. These data support a major role for CRF(1) in both the development and maintenance of visceral hyperalgesia induced by repeated stress and indicate a possible role of peripheral CRF receptors in such mechanisms.
AJP Gastrointestinal and Liver Physiology 05/2008; 294(4):G1033-40. · 3.43 Impact Factor
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01/2008: pages 90 - 101; , ISBN: 9780470760307
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ABSTRACT: Obestatin has been initially characterized as a new peptide derived from the ghrelin precursor, which suppresses food intake and inhibits the orexigenic and prokinetic actions of ghrelin when injected peripherally or centrally in lean mice. However, reproducing these data remains controversial. Reasons for the disparity may be the use of different doses, routes, and animal models. We aimed to investigate the effects of peripheral and intracisternal (IC) injection of obestatin on feeding, gastric motility, and blood glucose in rats as well as in diet-induced obese (DIO) mice.
Food intake and gastric emptying of a semi-liquid caloric meal were measured after intraperitoneal (IP) injection of obestatin in rats and DIO mice. Gastric phasic motility and blood glucose were monitored in urethane-anesthetized rats after IC or intravenous (IV) injection of obestatin.
Obestatin injected intraperitoneally at doses ranging from 0.1 to 3 mg/kg influenced neither acute food intake nor gastric emptying in rats. Obestatin injected intravenously at 0.3 or 3 mg/kg and IC at 7.5 or 30 microg/rat modified neither fasted gastric phasic motility nor blood glucose levels, while ghrelin (30 microg/kg, IV) increased and vagotomy suppressed gastric motility, and an oligosomatostatin analog (3 microg/rat, IC) decreased blood glucose. Obestatin, injected intraperitoneally (0.3 mg/kg) in DIO mice, did not alter feeding response to a fast, while urocortin 1 (10 microg/kg, IP) induced a 73.3% inhibition at 2 hours.
Our data demonstrate that peripheral administration of obestatin did not modify food intake in rats or obese mice or gastric motor function in rats.
Obesity 12/2007; 15(11):2643-52. · 4.28 Impact Factor
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ABSTRACT: Stress stimulates colonic motor function and plays a role in functional bowel disorders, prevalently in women. We examined, in conscious female rats, the influence of water avoidance stress for 60 min on colonic myenteric neuron activity using immunohistochemical detection of Fos as a marker of neuronal activity. In control rats, Fos immunoreactive nuclei were rare in proximal and distal colon and no defecation was observed. Water avoidance stimulated fecal pellet output, which was associated with Fos expression in myenteric ganglia of proximal and distal colon including in a population of peripheral choline acetyltransferase-immunoreactive neurons. Atropine blocked fecal pellet output but not Fos expression in myenteric ganglia. These results indicate that psychological stress stimulates the activity of colonic cholinergic myenteric neurons.
Neuroreport 05/2007; 18(7):679-82. · 1.66 Impact Factor
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Jean Rivier,
Jozsef Gulyas,
Koichi Kunitake,
Michael DiGruccio,
Jeffrey P Cantle,
Marilyn H Perrin,
Cindy Donaldson,
Joan Vaughan, Mulugeta Million,
Guillaume Gourcerol,
David W Adelson,
Catherine Rivier,
Yvette Taché,
Wylie Vale
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ABSTRACT: The potencies and selectivity of peptide CRF antagonists is increased through structural constraints, suggesting that the resulting ligands assume distinct conformations when interacting with CRF1 and CRF2 receptors. To develop selective CRF receptor agonists, we have scanned the sequence -Gln-Ala-His-Ser-Asn-Arg- (residues 30-35 of [DPhe12,Nle21,38]Ac-hCRF4-41) with an i-(i+3) bridge consisting of the Glui-Xaa-Xbb-Lysi+3 scaffold, where residues i=30, 31, and 32. When i=31, stressin1-A, a potent CRF1 receptor-selective agonist was generated. In vitro, stressin1-A was equipotent to h/rCRF to release ACTH. Astressin1-A showed a low nanomolar affinity for CRF1 receptor (Ki=1.7 nM) and greater than 100-fold selectivity versus CRF2 receptor (Ki=222 nM). Stressin1-A released slightly less ACTH than oCRF in adult adrenal-intact male rats, with increased duration of action. Stressin1-A, injected intraperitoneally in rats, induced fecal pellet output (a CRF1 receptor-mediated response) and did not influence gastric emptying and blood pressure (CRF2 receptor-mediated responses).
Journal of Medicinal Chemistry 05/2007; 50(7):1668-74. · 5.25 Impact Factor
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Jean Rivier,
Jozsef Gulyas,
Koichi Kunitake,
Michael Digruccio,
Jeffrey P Cantle,
Marilyn H Perrin,
Cindy Donaldson,
Joan Vaughan, Mulugeta Million,
Guillaume Gourcerol,
David W Adelson,
Catherine Rivier,
Yvette Taché,
Wylie Vale
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ABSTRACT: The potencies and selectivity of peptide CRF antagonists is increased through structural constraints, suggesting that the resulting ligands assume distinct conformations when interacting with CRF 1 and CRF 2 receptors. To develop selective CRF receptor agonists, we have scanned the sequence -Gln-Ala-His-Ser-Asn-Arg-(residues 30-35 of [DPhe 12 ,Nle 21,38 ]Ac-hCRF 4-41) with an i-(i+3) bridge consisting of the Glu i -Xaa-Xbb-Lys i+3 scaffold, where residues i) 30, 31, and 32. When i) 31, stressin 1 -A, a potent CRF 1 receptor-selective agonist was generated. In vitro, stressin 1 -A was equipotent to h/rCRF to release ACTH. Astressin 1 -A showed a low nanomolar affinity for CRF 1 receptor (K i) 1.7 nM) and greater than 100-fold selectivity versus CRF 2 receptor (K i) 222 nM). Stressin 1 -A released slightly less ACTH than oCRF in adult adrenal-intact male rats, with increased duration of action. Stressin 1 -A, injected intraperitoneally in rats, induced fecal pellet output (a CRF 1 receptor-mediated response) and did not influence gastric emptying and blood pressure (CRF 2 receptor-mediated responses).
Journal of Medicinal Chemistry 01/2007; · 4.80 Impact Factor
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ABSTRACT: We characterized the influence of the selective corticotropin-releasing factor 2 (CRF(2)) receptor agonist human urocortin 2 (Ucn 2), injected intracisternally, on gastric emptying and its mechanism of action compared with intracisternal CRF or urocortin (Ucn 1) in conscious rats. The methylcellulose phenol red solution was gavaged 20 min after peptide injection, and gastric emptying was measured 20 min later. The intracisternal injection of Ucn 2 (0.1 and 1 microg) and Ucn 1 (1 microg) decreased gastric emptying to 37.8 +/- 6.9%, 23.1 +/- 8.6%, and 21.6 +/- 5.9%, respectively, compared with 58.4 +/- 3.8% after intracisternal vehicle. At lower doses, Ucn 2 (0.03 microg) and Ucn 1 (0.1 microg) had no effect. The CRF(2) antagonist astressin(2)-B (3 microg ic) antagonized intracisternal Ucn 2 (0.1 microg) and CRF (0.3 microg)-induced inhibition of gastric emptying. Vagotomy enhanced intracisternal Ucn 2 (0.1 or 1 microg)-induced inhibition of gastric emptying compared with sham-operated group, whereas it blocked intracisternal CRF (1 microg) inhibitory action (45.5 +/- 8.4% vs. 9.7 +/- 9.7%). Sympathetic blockade by bretylium prevented intracisternal and intracerebroventricular Ucn 2-induced delayed gastric emptying, whereas it did not influence intravenous Ucn 2-, intracisternal CRF-, and intracisternal Ucn 1-induced inhibition of gastric emptying. Prazosin abolished the intracisternal Ucn 2 inhibitory effect, whereas yohimbine and propranolol did not. None of the pretreatments modified basal gastric emptying. These data indicate that intracisternal Ucn 2 induced a central CRF(2)-mediated inhibition of gastric emptying involving sympathetic alpha(1)-adrenergic mechanisms independent from the vagus contrasting with the vagal-dependent inhibitory actions of CRF and Ucn 1.
AJP Gastrointestinal and Liver Physiology 04/2006; 290(3):G511-8. · 3.43 Impact Factor
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Ines Schwetz,
James A McRoberts,
Santosh V Coutinho,
Sylvie Bradesi,
Greg Gale,
Michael Fanselow, Mulugeta Million,
Gordon Ohning,
Yvette Taché,
Paul M Plotsky,
Emeran A Mayer
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ABSTRACT: In rodents, maternal pup interactions play an important role in programming the stress responsiveness of the adult organism. The aims of this study were 1) to determine the effect of different neonatal rearing conditions on acute and delayed stress-induced visceral sensitivity as well as on other measures of stress sensitivity of the adult animal; and 2) to determine the role of corticotropin-releasing factor receptor (CRF-R) subtype 1 (CRF(1)R) in mediating visceral hypersensitivity. Three groups of male Long-Evans rat pups were used: separation from their dam for 180 min daily from postnatal days 2-14 (MS180), daily separation (handling) for 15 min (H), or no handling. The visceromotor responses (VMR) to colorectal distension, stress-induced colonic motility, and anxiety-like behavior were assessed in the adult rats. The VMR was assessed at baseline, immediately after a 1-h water avoidance (WA) stress, and 24 h poststress. Astressin B, a nonselective CRF-R antagonist, or CP-154,526, a selective CRF(1)R antagonist, was administered before the stressor and/or before the 24-h measurement. MS rats developed acute and delayed stress-induced visceral hyperalgesia. In contrast, H rats showed hypoalgesia immediately after WA and no change in VMR on day 2. MS rats with visceral hyperalgesia also exhibited enhanced stress-induced colonic motility and increased anxiety-like behavior. In MS rats, both CRF-R antagonists abolished acute and delayed increases in VMR. Rearing conditions have a significant effect on adult stress responsiveness including immediate and delayed visceral pain responses to an acute stressor. Both acute and delayed stress-induced visceral hypersensitivity in MS rats are mediated by the CRF/CRF(1)R system.
AJP Gastrointestinal and Liver Physiology 11/2005; 289(4):G704-12. · 3.43 Impact Factor
