Viscerosensory-cardiovascular reflexes : altered baroreflex sensitivity in irritable bowel syndrome

• Published in: American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2005-10, Vol.58 (4), p.R970-R976
• Main Authors: VAN DER VEEK, Patrick P. J, SWENNE, Cees A, VAN DE VOOREN, Hedde, SCHONEVELD, Annelies L, MAESTRI, Roberto, MASCLEE, Ad A. M
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Blood pressure; Bowel disease; Fundamental and applied biological sciences. Psychology; Heart; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Peripheral nervous system. Autonomic nervous system. Neuromuscular transmission. Ganglionic transmission. Electric organ; Reflexes; Vertebrates: nervous system and sense organs
• ISSN: 0363-6119; 1522-1490

Animal studies have demonstrated that visceral afferent stimulation alters autonomic cardiovascular reflexes. This mechanism might play an important role in the pathophysiology of conditions associated with visceral hypersensitivity, such as irritable bowel syndrome (IBS). As such, studies in humans are lacking, we measured viscerosensory-cardiovascular reflex interactions in IBS patients and healthy controls. Systolic blood pressure (SBP), heart rate (HR), and arterial baroreflex sensitivity (BRS) were studied in 87 IBS patients and 36 healthy controls under baseline conditions and during mild (15 mmHg) and intense (35 mmHg) visceral stimulation by rectal balloon distension. BRS was computed from continuous ECG and arterial blood pressure signals (Finapres-method) during 5-min periods of 15-min metronome respiration. Baseline SBP and HR were not different between patients and controls. In both groups, SBP increased similarly during rectal stimulation, whereas HR decreased during mild and increased intense stimulation. BRS was significantly higher in patients compared with controls at baseline (7.9 plus or minus 5.4 vs. 5.7 plus or minus 3.7 ms/mmHg, P = 0.03) and increased significantly in both groups during mild stimulation. This increase persisted in controls during intense stimulation, but BRS returned to baseline in patients. BRS was not significantly different between groups during rectal distension. This study demonstrates the presence of a viscerosensory-cardiovascular reflex in healthy individuals and in IBS patients. The increased BRS in IBS patients at baseline may either be a training-effect (frequent challenging of the reflex) or reflects altered viscerosensory processing at the nucleus tractus solitarii.[PUBLICATION ABSTRACT]