Visceral sensitivity in explaining functional bowel disorders : from concepts to clinical practice

Functional digestive disorders (FDD) consist of several syndromes characterized by the absence of any organic or biochemical abnormality and mainly defined by a cluster of symptoms more or less related to one segment of the gut (1). The most frequent and most studied of them are Non-Ulcer Dyspepsia (NUD) and Irritable Bowel Syndrome (IBS). Abdominal pain is the most f equent complaint of these patients. It may result from organic or functional disorders and may be related to different neurophysiological mechanisms. Classical aetiological theories have implicated psycho-social factors and abnormalities in gastrointestinal motility. Consequently to this hypothesis, most of the prevailing therapeutic approaches to resolve pain in patients with FDD have focused on motility patterns, using antispasmodics, bulk-forming agents and more recently prokinetic compounds. These drugs are mainly acting on the efferent nerve pathways controlling the function of digestive muscle. Over the last decade, a large attention has been paid to the role of visceral sensitivity in the pathophysiology of FDD and especially the Irritable Bowel Syndrome (IBS) (see Rev. Mayer Raybould) (2). These studies have enlightened the role of nerve afferent pathways arising from the gut and processing information to the peripheral and central nervous systems and thereby triggering a number of reflexes. The afferent nerve pathways have thus been recognized as a possible target for new treatments aimed to relief pain in patients with FDD.