Volume 140, Issue 5, Pages 1586-1596.e6 (May 2011) Activation of Corticotropin-Releasing Factor Receptor 2 Mediates the Colonic Motor Coping Response to Acute Stress in Rodents  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  Gastroenterology  Volume 140, Issue 5, Pages 1586-1596.e6 (May 2011) DOI: 10.1053/j.gastro.2011.01.039 Copyright © 2011 AGA Institute Terms and Conditions

Figure 1 Peripheral pretreatment (–5 min) with hUcn 2 blunts IP CRF-induced defecation and colonic myenteric Fos IR whereas astressin2-B enhances the response in rats. (A) Defecation response, expressed as fecal pellet output (fpo) to IP CRF in the presence or not of IP hUcn 2. *P < .05 vs controls; #P < .05 vs CRF; n = 8–11/group. (B) Confocal photomicrograph of proximal colon LMMP neurons Fos expression. Colons are from rats in panel A (8/group) that received IP water + saline (top left), water + CRF (top right), hUcn 2 + saline (bottom left), and hUcn 2 + CRF (bottom right). (C) Fos-IR (cell/ganglion) in the proximal, distal, and proximal-distal colon in response to CRF (3 μg/kg, IP) in the presence or not of hUcn 2 (10 μg/kg, IP). *P < .05 vs all others; #P < .05 vs their respective water + saline (sal) or Ucn 2 + sal; n = 8/group. (D and E) Selective blockade of CRF2 receptor by IP astressin2-B exacerbated IP CRF-induced (D) defecation and (E) diarrhea. Bar, mean ± standard error of the mean. n = 8/group. *P < .05 vs water + saline or astressin2-B + saline; #P < .05 vs the corresponding (D and E) water + CRF 10 μg/kg or (E) water + CRF 3 or 10 μg/kg. Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions

Figure 2 Acute partial-restraint stress-induced colonic contractions in rats is prevented by hUcn 2 (10 μg/kg, IP). (A) Representative solid-state manometry trace with pressure sensor catheter probes placed in the colon at 8 and 4 cm past the anus. (B) Graphs showing amplitude, duration, total frequency (>15 mm Hg), and propagated contraction frequency. Bar, mean ± standard error of the mean of n = 5/group. *P < .05 vs water. (C) Time-course of AUC pressure changes. Dotted arrows show IP injection just before the onset of restraint stress. Values are rolling averages (mean ± standard error of the mean) of AUC computed for every 5 minutes. *P < .05 vs contractile responses on all other time points. n = 8/group. Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions

Figure 3 mUcn 2 (10 μg/kg) injected IP reduced distal colonic contraction to acute partial restraint stress in wild-type mice. (A) Representative distal colonic contractile activity traces after saline or mUcn 2 treatment. Time-course of AUC pressure changes (B) over 1 hour and (C) in blocks of 0–20 and 20–60 minute periods. Bar, mean ± standard error of the mean of n = 8–10/group. *P < .05; **P < .01 vs saline. (D and E) Plots show distal colonic contractions pattern of WTL mice during the first 20 minutes of PRS after injection with (D) saline or (E) mUcn 2. Plots show the frequency of contractions as a function of amplitude or duration of contractions. (F) Distal colonic contraction profile (frequency, amplitude, and duration of contractions), including GMCs over a 1-hour period. Bar, mean ± standard error of the mean of n = 6 mice/group. *P < .05 vs saline; **P < .01 vs saline. Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions

Figure 4 mUcn 2 (10 μg/kg, IP) reduces distal colonic contractions to acute partial restraint stress in CRF-OE mice. (A and B) Representative distal colonic contractile activity traces of CRF-OE mice injected with (A) saline or (B) mUcn 2. (C and D) Time-course of the AUC of intracolonic pressure changes (C) over 1 hour and (D) in blocks of 0–20, 0–60 minutes. Bar, mean ± standard error of the mean of n = 6–7/group. *P < .05, **P < .01 vs saline. Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions

Figure 5 Distal colonic contractions to acute partial restraint are enhanced in CRF2–/– mice compared with wild-type. (A and B) Representative trace in (A) WTL mouse and (B) CRF2–/– mouse. Time-course of AUC of intracolonic pressure changes (C) over 1 hour and (D) in blocks of 0–20 and 0–60-minute periods. Bar, mean ± standard error of the mean of n = 7/group. *P < .05 vs WTL 0–20 minute time period; #P < .05 vs WTL 0–60 minute time period. Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions

Figure 6 CRF1 and CRF2 are coexpressed in rat colonic myenteric neurons. (A and B) Confocal microscope images showing double labeling of (A) CRF2 with CRF1 and (B) CRF2 with nNOS in rat distal colon whole-mount LMMP preparation. (C) Double labeling of nuclear marker, 4′,6-diamidino-2-phenylindole (dapi) and anti-Hu IR in rat colon myenteric ganglion primary culture neurons (top panel) and double labeling of CRF2 with CRF1 (middle panel). Lower panels in A, B, and C show negative control, stained with normal goat immunoglobulin G. (D) Western blot analysis of CRF1 (bands at 39, 50, 60, and 75 kilodaltons, arrows) and CRF2 (at 42 and 55 kilodaltons, arrows) in proximal colon (pc) and distal colon (dc) PC-LMMPn. (E) Reverse-transcription PCR analysis for expression of CRF1, CRF2a, and CRF2b splice variants in the rat proximal colon PC-LMMPn. Hypothalamus (Hyp) was used as positive control for CRF1 and esophagus (Eso) for CRF2a and CRF2b to generate predicted PCR products (arrows). Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions

Figure 7 Activation of CRF2 suppresses phosphorylation of pERK in PC-LMMPn and cAMP production in HEK-293 cells. (A and B) Western blot analysis of pERK1/2 in response to CRF, Ucn 1, or Ucn 2 (A) and blockade of the CRF-induced pERK by Ucn 2 or by a selective CRF1 antagonist, NBI-3965, and enhancement of the response by selective CRF2 antagonist astressin2-B (B). Bar, mean ± standard error of the mean, n = 3/group. *P < .05 vs no treatment and the respective 10-nmol/L dose in panel A, †P < .05 vs all other groups in panel A, #P < .05 vs no treatment and the respective CRF or Ucn 1–alone dose in panel A. (C) Dose-dependent increases in intracellular cAMP production in CRF1α, CRF2β, and CRF1α+CRF2β–transfected HEK-293 cells stimulated with CRF for 30 minutes. Note the 10-fold decrease in potency of CRF in CRF1 and CRF2 coexpressing cells vs in CRF1-only expressing cells. Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions

Supplementary Figure 1 Confocal microscope images showing double labeling of (A) CRF2 with CRF1 and (B) CRF2 with nNOS in rat proximal colon whole-mount LMMP preparation. Gastroenterology 2011 140, 1586-1596.e6DOI: (10.1053/j.gastro.2011.01.039) Copyright © 2011 AGA Institute Terms and Conditions