233 PROBING CENTRAL NORADRENERGIC ACTIVITY IN IRRITABLE BOWEL SYNDROME PATIENTS WITH YOHIMBINE AND CLONIDINE: A PILOT STUDY. Issue 1 (1st January 2007)

• Record Type: Journal Article
• Authors: Huang, E.; Naliboff, B. D.; Tillisch, K.; Mayer, E. A.
• Is Part Of: Journal of investigative medicine. Volume 55:Issue 1(2007)
• Page Start: S114
• Page End: S114
• Publication Date: 2007-01-01
• Subjects: Clinical medicine -- Periodicals; Medicine -- Research -- Periodicals; Medicine; Research -- United States; Clinical medicine; Medicine -- Research; Periodicals; 616.075
• Languages: English
• ISSNs: 1081-5589

Abstract

Abstract : Background: Irritable bowel syndrome (IBS) is conceptualized as a syndrome of enhanced central stress circuit responsiveness, likely associated with altered adrenergic and autonomic responses. Aims: (1) To determine if baseline autonomic nervous system (ANS) differences exist in IBS versus control subjects; (2) to determine group differences in ANS response to yohimbine (YOH) and clonidine (CLO); and (3) to determine group differences in the effects of YOH and CLO on affective states. Methods: IBS and control subjects were enrolled. ANS and affective measures were taken before and after drug ingestion. ANS was measured by HRV (high frequency, HF, indicating cardiovagal and low/high frequency ratio, LF/HF, indicating sympathetic) and systolic BP. Affective ratings were made with the Stress Symptom Rating Questionnaire. Results: Mean baseline HF was lower in IBS versus controls (34.29 nu vs 62.88 nu, p = .013). Mean baseline LF/HF was higher in IBS versus controls (2.59 vs 0.91, p = .057). No significant HRV changes were seen in response to CLO or YOH in either group. YOH significantly increased BP ( p = .01) and CLO significantly reduced BP ( p = .02) in pooled subjects; no group difference in BP was seen. No group differences in affective ratings were seen. In combined groups, YOH increased anxiety ( p = .05) and CLO led to increased fatigue ( p = 0.01) with decreased arousal ( p = .02). Conclusion: These findings confirm that there is greater baseline sympathetic and lower parasympathetic activity in IBS patients compared with controls. A larger sample of patients is likely needed to elucidate group differences in drug responses.