Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society
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Neurogastroenterol. Motil. · Jan 2016
Excessive coupling of the salience network with intrinsic neurocognitive brain networks during rectal distension in adolescents with irritable bowel syndrome: a preliminary report.
The neural network mechanisms underlying visceral hypersensitivity in irritable bowel syndrome (IBS) are incompletely understood. It has been proposed that an intrinsic salience network plays an important role in chronic pain and IBS symptoms. Using neuroimaging, we examined brain responses to rectal distension in adolescent IBS patients, focusing on determining the alteration of salience network integrity in IBS and its functional implications in current theoretical frameworks. We hypothesized that (i) brain responses to visceral stimulation in adolescents are similar to those in adults, and (ii) IBS is associated with an altered salience network interaction with other neurocognitive networks, particularly the default mode network (DMN) and executive control network (ECN), as predicted by the theoretical models. ⋯ Our study provided consistent evidence supporting the theoretical predictions of altered salience network functioning as a neuropathological mechanism of IBS symptoms.
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Neurogastroenterol. Motil. · Jan 2016
Altered brain responses in subjects with irritable bowel syndrome during cued and uncued pain expectation.
A majority of the subjects with irritable bowel syndrome (IBS) show increased behavioral and brain responses to expected and delivered aversive visceral stimuli during controlled rectal balloon distension, and during palpation of the sigmoid colon. We aimed to determine if altered brain responses to cued and uncued pain expectation are also seen in the context of a noxious somatic pain stimulus applied to the same dermatome as the sigmoid colon. ⋯ The observed greater engagement of cognitive and emotional brain networks in IBS subjects during contextual threat may reflect the propensity of IBS subjects to overestimate the likelihood and severity of future abdominal pain.
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Neurogastroenterol. Motil. · Dec 2015
Abnormal regional homogeneity in patients with irritable bowel syndrome: A resting-state functional MRI study.
Task-related brain imaging research has implicated abnormal central processing of visceral sensation in irritable bowel syndrome (IBS). However, how brain function of IBS patients is altered during resting-state remains to be determined. We investigated spontaneous brain activity of patients with IBS using regional homogeneity (ReHo) analysis in resting-state functional magnetic resonance imaging (rs-fMRI). ⋯ IBS patients have abnormal local synchronization of spontaneous brain activity in regions involved in visceral afferent processing, emotional arousal, and cognitive modulation. Combining rs-fMRI and ReHo analysis seems to be a valuable approach to investigate the neural basis of IBS.
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Neurogastroenterol. Motil. · Oct 2015
The GPR55 antagonist CID16020046 protects against intestinal inflammation.
G protein-coupled receptor 55 (GPR55) is a lysophospholipid receptor responsive to certain cannabinoids. The role of GPR55 in inflammatory processes of the gut is largely unknown. Using the recently characterized GPR55 inhibitor CID16020046, we determined the role of GPR55 in experimental intestinal inflammation and explored possible mechanisms of action. ⋯ Pharmacological blockade of GPR55 reduces experimental intestinal inflammation by reducing leukocyte migration and activation, in particular that of macrophages. Therefore, CID16020046 represents a possible drug for the treatment of bowel inflammation.