Migrating motor complex (MMC) is well characterized by the appearance of gastrointestinal contractions in the interdigestive state. This review article discussed the mechanism of gastrointestinal MMC. Luminal administration of 5-hydroxytryptamine (5-HT) initiates duodenal phase II followed by gastrointestinal phase III with a concomitant increase of plasma motilin release in conscious dogs. Duodenal 5-HT concentration is increased during gastric phase II and phase III. Intravenous infusion of motilin increases luminal 5-HT content and induces gastrointestinal phase III. 5-HT4 antagonists significantly inhibits both of gastric and intestinal phase III, while 5-HT3 antagonists inhibited only gastric phase III. These suggest that gastrointestinal MMC cycle is mediated via the interaction between motilin and 5-HT by the positive feedback mechanism. Gastric MMC is regulated via vagus, 5-HT3/4 receptors and motilin, while intestinal MMC is regulated via intrinsic primary afferent neurons and 5-HT4 receptors. Stress is highly associated with the pathogenesis of functional dyspepsia. Acoustic stress attenuates gastric phase III without affecting intestinal phase III in conscious dogs, via reduced vagal activity and increased sympathetic activity. It has been shown that subset of functional dyspepsia patients show reduced vagal activity and impaired gastric phase III. The physiological importance of gastric MMC is a mechanical and chemical cleansing of the empty stomach in preparation for the next meal. The impaired gastric MMC may aggravate dyspeptic symptoms following a food ingestion. Thus, maintaining gastric MMC in the interdigestive state is an important factor to prevent the postprandial dyspeptic symptoms.
Acoustics ; Animals ; Autonomic Pathways ; Contracts ; Dogs ; Dyspepsia ; Eating ; Enterochromaffin Cells ; Humans ; Infusions, Intravenous ; Meals ; Motilin ; Myoelectric Complex, Migrating ; Neurons, Afferent ; Phenobarbital ; Plasma ; Receptors, Serotonin, 5-HT4 ; Serotonin ; Serotonin 5-HT3 Receptor Antagonists ; Serotonin 5-HT4 Receptor Antagonists ; Stomach

While constipation is a common symptom in Korea, there are no existing treatment guidelines. Although constipation may occur as a result of organic cause, there is no obstructive mucosal or structural cause in the vast majority of patients with constipation. The present paper deals with only the management of functional constipation: lifestyle changes; bulking agents and stool softeners; osmotic agents; stimulant laxatives; prokinetics; biofeedback and surgical treatments. Exercise and dietary fiber are helpful in some patients with constipation. Laxatives including bulking agents, stool softeners, osmotic agents, and stimulant laxatives have been found to be more effective than placebo at relieving symptoms of constipation. New enterokinetic agents that affect peristalsis through selective interaction with 5-hydroxytryptamine-4 receptors can be effective in patients with constipation who cannot get adequate relief from current laxatives. Biofeedback can relieve symptoms in selected patients with pelvic floor dyssynergia. Surgical treatments can be helpful in some patients with refractory constipation.
Biofeedback, Psychology ; Cathartics/therapeutic use ; Constipation/surgery/*therapy ; Dietary Fiber/therapeutic use ; Electric Stimulation Therapy ; Exercise Therapy ; Health Behavior ; Humans ; Laxatives/therapeutic use ; Serotonin 5-HT4 Receptor Antagonists/therapeutic use ; Surface-Active Agents/therapeutic use

Irritable bowel syndrome is a group of symptoms that includes abdominal pain and changes in the form and frequency of stool. Since its symptoms are usually long-lasting, the disease significantly degrades quality of life. Several pharmacological therapies have been suggested according to the type of symptoms (e.g., abdominal pain, constipation, or diarrhea). In order to control abdominal pain, smooth muscle antispasmodics, antidepressants including tricyclic antidepressants and selective serotonin reuptake inhibitors, or 5-HT3 antagonists can be used. To improve constipation, dietary fiber or laxatives, 5-HT4 agonists, and chloride channel activators are available. Opioid agonists, mixed opioid agonists/antagonists such as eluxadoline, and bile salt sequestrants can be considered for diarrhea. In addition, probiotics and non-absorbable oral antibiotics can be used for the normalization of the gut microbiome and the treatment of small intestinal bacterial overgrowth, respectively. It is necessary to understand the characteristics of each drug and their combinations, because any single regimen cannot improve all symptoms in patients with irritable bowel syndrome. In this review, the mechanisms of action, efficacy, and adverse events associated with drugs used for irritable bowel syndrome are summarized.
Abdominal Pain ; Anti-Bacterial Agents ; Antidepressive Agents ; Antidepressive Agents, Tricyclic ; Bile ; Chloride Channel Agonists ; Constipation ; Diarrhea ; Dietary Fiber ; Drug Therapy* ; Gastrointestinal Microbiome ; Humans ; Irritable Bowel Syndrome* ; Laxatives ; Muscle, Smooth ; Parasympatholytics ; Probiotics ; Quality of Life ; Serotonin 5-HT3 Receptor Antagonists ; Serotonin 5-HT4 Receptor Agonists ; Serotonin Uptake Inhibitors

Irritable bowel syndrome is a group of symptoms that includes abdominal pain and changes in the form and frequency of stool. Since its symptoms are usually long-lasting, the disease significantly degrades quality of life. Several pharmacological therapies have been suggested according to the type of symptoms (e.g., abdominal pain, constipation, or diarrhea). In order to control abdominal pain, smooth muscle antispasmodics, antidepressants including tricyclic antidepressants and selective serotonin reuptake inhibitors, or 5-HT3 antagonists can be used. To improve constipation, dietary fiber or laxatives, 5-HT4 agonists, and chloride channel activators are available. Opioid agonists, mixed opioid agonists/antagonists such as eluxadoline, and bile salt sequestrants can be considered for diarrhea. In addition, probiotics and non-absorbable oral antibiotics can be used for the normalization of the gut microbiome and the treatment of small intestinal bacterial overgrowth, respectively. It is necessary to understand the characteristics of each drug and their combinations, because any single regimen cannot improve all symptoms in patients with irritable bowel syndrome. In this review, the mechanisms of action, efficacy, and adverse events associated with drugs used for irritable bowel syndrome are summarized.
Abdominal Pain ; Anti-Bacterial Agents ; Antidepressive Agents ; Antidepressive Agents, Tricyclic ; Bile ; Chloride Channel Agonists ; Constipation ; Diarrhea ; Dietary Fiber ; Drug Therapy* ; Gastrointestinal Microbiome ; Humans ; Irritable Bowel Syndrome* ; Laxatives ; Muscle, Smooth ; Parasympatholytics ; Probiotics ; Quality of Life ; Serotonin 5-HT3 Receptor Antagonists ; Serotonin 5-HT4 Receptor Agonists ; Serotonin Uptake Inhibitors

Traditional symptom-based therapies of irritable bowel syndrome (IBS) are directed at the relief of individual IBS symptoms, but they are often of limited efficacy in addressing the entire symptom complex. Combinations of drugs to target bothersome symptoms are suggested as the first-line pharmacologic treatment. Increasing knowledge of the pathophysiology and molecular mechanisms of IBS has resulted in the development of several new therapeutic approaches. Thirteen consensus statements for the treatment of IBS were developed using the modified Delphi approach. Exclusion diets have modest efficacy in improving symptoms in some IBS patients. Symptom-based therapies with dietary fiber, bulking agents, laxatives, antispasmodics and laxatives are effective in the improvement of some individual symptoms, e.g. dietary fiber and bulking agents for constipation, laxatives for constipation, antispasmodics for abdominal pain and discomfort, antidiarrheals for diarrhea. 5HT3 receptor antagonists and 5HT4 receptor agonists are effective in the relief of global IBS symptoms and individual symptoms such as abdominal pain and abnormal bowel habits. A short term course of nonabsorbable antibiotics may improve global IBS symptoms, particularly in patients with diarrhea- predominant IBS. Some probiotics appear to have the potential benefit in improving global IBS symptoms. Selective C-2 chloride channel activator is more effective than placebo at relieving global IBS symptoms in patients with constipation-predominant IBS. Both tricyclic antidepressants and selective serotonin reuptake inhibitors are equally effective in relieving global IBS symptoms, and have some benefits in treating abdominal pain. Certain types of psychologic therapy may be effective in improving global symptoms in some IBS patients. Further studies are strongly needed to develop better treatment strategies for Korean patients with IBS.
Anti-Infective Agents/therapeutic use ; Antidepressive Agents/therapeutic use ; Antidiarrheals/therapeutic use ; Dietary Fiber/therapeutic use ; Humans ; Irritable Bowel Syndrome/*therapy ; Laxatives/therapeutic use ; Parasympatholytics/therapeutic use ; Probiotics/therapeutic use ; Serotonin 5-HT4 Receptor Agonists/therapeutic use ; Serotonin Antagonists/therapeutic use