Increased β-Adrenergic Sensitivity Correlates with Visceral Hypersensitivity in Patients with Constipation-Predominant Irritable Bowel Syndrome

Abstract

Autonomic imbalance has been proposed to be a pathophysiological factor for irritable bowel syndrome (IBS). The aim of this study was to assess beta-adrenergic abnormalities in IBS and to evaluate their relationship to visceral hypersensitivity and other symptoms of IBS patients. Sixteen IBS patients and 16 control subjects were recruited into this study. Participants were asked to complete a questionnaire regarding bowel symptoms, and in order to study beta-adrenergic sensitivity, isoproterenol stimulation tests were performed and visceral hypersensitivity was evaluated by barostat test. Results showed that beta-adrenergic activity and rectal sensitivity were more pronounced in IBS patients than in normal control patients (P < 0.01). Although both IBS subgroups also exhibited more pronounced beta-adrenergic sensitivity than did the controls (P < 0.05), a significant correlation between beta-adrenergic activity and maximally tolerable pressures on the barostat test was found only in IBS-C patients (P = 0.03, R = 0.855). In addition, patients with "hard or lumpy" stools exhibited a higher degree of beta-adrenergic activity (P = 0.00). We conclude that increased beta-adrenergic activity significantly correlated with visceral hypersensitivity in constipation-predominant IBS and symptoms of hard or lumpy stools in IBS patients.

Psychological Co-morbidity in Functional Gastrointestinal Disorders: Epidemiology, Mechanisms and Management

“…Hyperactivity of the neuroendocrine and visceral perceptual response to physiological (eg, meal) or psychological stimuli may account for the stress-induced flare of bowel symptoms in IBS patients,17,18 and administration of CRF alleviates visceral hyperalgesia and negative affective response to bowel stimulation in IBS patients 19. Increased beta-adrenergic activity is significantly correlated with visceral hypersensitivity and symptoms of hard or lumpy stools in constipation-predominant IBS 20. It has also been reported that anxiety induces gastric sensorimotor dysfunction and postprandial symptoms in patients with functional dyspepsia 21…”

Characterization of autonomic dysfunction in patients with irritable bowel syndrome using fingertip blood flow

“…Numerous studies have been undertaken to assess autonomic imbalance as a factor underlying the pathogenesis of IBS, considering that experimental stress increases sympathetic activity and also alters gastrointestinal motor responses 6–8 …”

Changes in salivary physiological stress markers induced by muscle stretching in patients with irritable bowel syndrome

“…Autonomic imbalance has been proposed as a pathophysiological factor of IBS. Adrenergic neural activity and rectal sensitivity are more pronounced in IBS patients than in normal controls [ 12 ]. The stress response system includes the sympathetic/adrenomedullary (S/A) system and the hypothalamic-pituitary-adrenal (HPA) axis.…”