Study of Endogenous Inhibitory Modulation During Gastric and Somatic Stimulation

Visceral hypersensitivity as evidence of central sensory sensitization is evident in many patients with functional disorders such as functional dyspepsia (FD) and irritable bowel syndrome (IBS). We recently demonstrated both somatic hypersensitivity and abnormal endogenous pain modulation in IBS, both of which indicate central sensitization as a crucial mechanism in IBS. Endogenous pain mechanisms regulate, fine-tune and integrate sensory and homeostatic, including neuroendocrine, immune, motor and autonomic nervous system processes. Hitherto, no studies have investigated the role endogenous pain modulation in FD. Abnormal modulation could explain several of the symptom complexes associated with FD and provide a rationale for exploration of new treatments. The current study was designed to 1. investigate the gastric sensitivity in FD patients and healthy controls during gastric capsaicin stimulation 2. assess the endogenous pain inhibitory modulation system in FD patients and healthy controls during heterotopic stimulation