22, 23 and 30 High-threshold splanchnic nociceptors were investigated in intact colonic preparations and in those where the mucosa had been removed. Mice received an enema of either saline or linaclotide (1000 nM). Five minutes Epigenetics inhibitor later, under anesthesia, a 4-cm CRD balloon catheter was inserted transanally into healthy or CVH mice.26 After regaining consciousness, CRD was performed (80 mmHg for 10 seconds, then deflated for 5 seconds and repeated 5 times). After sacrifice via anesthetic overdose, mice underwent fixation by transcardial

perfusion and the thoracolumbar (T10−L1) spinal cord was removed and cryoprotected. Frozen sections were cut and incubated with monoclonal rabbit anti−phosphorylated MAP kinase ERK 1/2 (pERK) with AlexaFluorR488 used for visualization. Quantitative polymerase chain reaction was performed using mouse-specific Gucy2c and glyceraldehyde-3-phosphate dehydrogenase Taqman probes on complementary DNAs synthesized from total RNAs extracted from a panel of mouse tissues. For in situ hybridization, sections were hybridized overnight at 55°C with either 35S-labeled complementary RNA anti-sense or sense probes

to Gucy2c. Cells were grown in monolayers and stimulated for 1 hour with linaclotide (1000 nM) in the presence or absence of the cGMP transporter inhibitor probenecid (0.5 mM or 2 mM). Samples from the basolateral chambers were collected and cGMP concentrations determined by liquid chromatography

mass spectrometry. Electrical field stimulation was applied to colonic tissues in the presence and absence of linaclotide Tyrosine Kinase Inhibitor Library concentration or membrane permeable 8-bromo-cGMP. Contraction amplitude was compared between each condition. The current results are from a post-hoc efficacy analysis of a phase III, double-blind, parallel-group, placebo-controlled trial that randomized 805 IBS-C patients to placebo or 290 μg oral linaclotide once daily for a 26-week treatment period. The current efficacy Clomifene analysis are based on a responder end point for abdominal pain, specified as part of a co-primary end point recommended in the May 2012 US Food and Drug Administration final guidance for industry on the clinical evaluation of products for IBS,28 defined as a ≥30% improvement from baseline in average daily worst abdominal pain score.28 We present, for the first time, an evaluation of this abdominal pain responder end point for each week of the 26-week treatment period, comparing treatment and control groups. We hypothesized that linaclotide reduces abdominal pain in IBS-C patients17 via an inhibitory action on colonic nociceptors. In order to test this hypothesis in mice, we performed in vitro single-unit afferent recordings. First, we investigated if linaclotide affected the mechanosensitivity of colonic nociceptors from healthy mice.