Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0013395 (dyspepsia)
 4,879 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serotonin (5-hydroxytryptamine; 5-HT) is found in the enteric nervous system where it has been implicated in controlling gastrointestinal motor function. A number of receptor or recognition sites have been identified in the gut, but recently most attention has focused on the 5-HT3 and 5-HT4 receptors. The functional role of the 5-HT3 receptor remains incompletely understood, but it is probably involved in the modulation of colonic motility and visceral pain in the gut. A number of selective 5-HT3 antagonists have been developed including ondansetron, granisetron, tropisetron renzapride and zacopride. While the substituted benzamide prokinetics (for example, metoclopramide, cisapride) also block 5-HT3 receptors in high concentrations, their prokinetic action is believed to be on the basis of their agonist effects on the putative 5-HT4 receptor. Some 5-HT3 antagonists have 5-HT4 agonist activity (for example, renzapride, zacopride) and others do not (for example, ondansetron, granisetron), while tropisetron in high concentrations is a 5-HT4 antagonist. Based on the pharmacological data, it has been suggested that specific 5-HT antagonists and agonists may prove to be beneficial in a number of gastrointestinal disorders including the irritable bowel syndrome, functional dyspepsia, non-cardiac chest pain, gastrooesophageal reflux and refractory nausea. In this review, the rationale for the use of these compounds is discussed, and the available experimental evidence is summarized.
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PMID:Review article: 5-hydroxytryptamine agonists and antagonists in the modulation of gastrointestinal motility and sensation: clinical implications. 160 46

A greater understanding of the various serotonin receptor subtypes has led to a clearer appreciation of the role of serotonin in gastrointestinal motility, sensation and secretion. Serotonin is definitely involved in the aetiopathogenesis of cisplatin-induced emesis and carcinoid diarrhoea. The application of serotonergic drugs in clinical therapeutics for gut disturbances is presently dominated by the use of 5-HT3 antagonists for acute chemotherapy-induced nausea and vomiting, and the use of substituted benzamides which are 5-HT4 agonists stimulating gut motor function through 5-HT4 neuronal receptors. The best-studied 5-HT4 agonist is cisapride, which has been shown to stimulate motility at several levels of the gut. Cisapride is approved for healing and maintenance treatment of reflux oesophagitis and is used in several countries for the alleviation of symptoms consistent with regional stasis, from dyspepsia to constipation. Carcinoid diarrhoea is a prototypic disease associated with deranged serotonin metabolism, and a rationale for using 5-HT3 or 5-HT4 antagonists is based on the recent appreciation of the important role of impaired gut motor function in carcinoid diarrhoea. In the future, greater understanding of the serotonin receptor subtypes and their role in gut disorders may lead to novel approaches to alleviate increased visceral perception of functional gastrointestinal disorders, to correct changes in colonic capacitance, or to alter gastrointestinal motility that contributes to diarrhoea or constipation. However, at the present time, it must be stressed that these uses are still at an experimental stage and that careful validation and proper controlled studies are still required.
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PMID:Drugs affecting serotonin receptors. 794 60

Gastrointestinal prokinetics promote or increase the coordination of the gut wall contractions leading to enhancement of propulsive motility and, consequently, caudal displacement of luminal contents. Currently, they are considered drugs of choice for the treatment of upper gastrointestinal tract functional motor disorders such as those associated with gastrooesophageal reflux disease, chronic dyspepsia, gastroparesis (idiopathic or secondary to other diseases) and acute or chronic idiopathic intestinal pseudo-obstruction. The aim of the present review is to give an outline of the pharmacology of currently available prokinetics and of novel drugs endowed with gastrointestinal prokinetic action that require further pharmacological and/or clinical testing. The novel drugs include recent generations of benzamide and non-benzamide 5-HT4 receptor agonists, motilin receptor agonists, and inhibitors of nitric oxide synthase. Furthermore, based on our improved knowledge of the role of 5-HT in emesis and gastrointestinal motility, the therapeutic potential of potent mixed 5-HT4 agonists--5-HT3 antagonists in the control of cytotoxic-drug-induced emesis and associated gut motor disturbances will be discussed. Lastly, a section of this review deals with the colon as a possible target for the action of prokinetics.
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PMID:Recent advances in the pharmacology of gastrointestinal prokinetics. 893 12

Several serotonin (5-HT) receptor subtypes have been defined by pharmacological responses to selective agonists and antagonists and by pathways of receptor-effector coupling. Using molecular techniques, additional receptor subtypes have been described. 5-HT receptors are prevalent in the central nervous system and gut and participate in induction of emesis. 5-HT3 antagonists are used to prevent emesis from cancer chemotherapy and also demonstrate efficacy in radiation-induced nausea, postoperative nausea, hyperemesis gravidarum, and nausea and vomiting with the acquired immunodeficiency syndrome. 5-HT4 agonists exhibit prokinetic properties in nauseated patients with gastroparesis and functional dyspepsia. Conversely, 5-HT4 antagonists have antiemetic activity in some experimental models. The 5-HT1D receptor agonist sumatriptan reduces emesis with migraine headaches and in cyclic vomiting syndrome, most likely via action on central nervous system sites. In other models, 5-HT1A and 5-HT2A/5-HT2C agonists exhibit antiemetic properties. The utility of 5-HT receptor ligands in treating emesis is the subject of active investigation.
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PMID:Serotonin receptor physiology: relation to emesis. 1049 49

The evaluation and management of gastric motor dysfunction continues to represent a significant clinical challenge. The very definition of what constitutes a clinically relevant disturbance of gastric motility remains unclear. The spectrum of gastroparesis extends from those with classical symptoms and severe delay of gastric emptying to those with dyspepsia and a mild delay in emptying rate. Indeed, for many patients with dyspepsia, the role of gastric emptying delay in the pathogenesis of symptoms, remains unclear. Any assessment of the efficacy of any therapeutic class in gastroparesis must be mindful, therefore, of these variations in definition. For those individuals with severe established gastroparesis, therapeutic success often remains elusive and i.v. erythromycin and oral dopamine antagonists, or substituted benzamides, remain the best options for acute severe exacerbations and chronic maintenance therapy, respectively. Alternatives, currently under investigation, include a number of 5-HT4 agonists, macrolides devoid of antibiotic activity, CCK antagonists and gastric electrical stimulation. Other novel approaches include strategies to address some of the regional abnormalities in gastric motor function that have been identified in some patients with dyspepsia.
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PMID:Pharmacotherapy of gastroparesis. 1124 97

Drug development for functional gastrointestinal disorders is complex. These conditions involve central and peripheral physiological changes, together with psychological factors. Methodological problems have included a poor appreciation of the physiological and psychological correlates of patients' symptoms, a lack of animal models of proven relevance, and safety issues. Government, patient pressure groups and the Internet can also influence a drug's success. Most recent interest has focused on the serotonin (5-HT) modifying drugs. Cisapride has been withdrawn in some countries because of concerns related to QT prolongation and cardiac arrhythmias. The 5-HT3 antagonists, developed to modify visceral sensation, have caused constipation; alosetron, also withdrawn, caused ischaemic colitis. The 5-HT4 agonists induce peristalsis; tegaserod and prucalopride, both delayed in their development due to issues of safety and efficacy, benefit patients with 'constipation-predominant' irritable bowel syndrome or idiopathic constipation. 5-HT1 agonists improve impaired gastric accommodation and symptoms in patients with functional dyspepsia. Antidepressants also affect serotonin metabolism. Previous examples of success in this area involved drugs targeted at peripheral receptors mediating motor function or secretion. Modification of sensory function is a much more challenging objective. The experience with serotonin modifying drugs has been mixed, and some important lessons are there to be learnt.
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PMID:Review article: the complexity of drug development for irritable bowel syndrome. 1187 86

Antidopaminergic gastrointestinal prokinetics (bromopride, clebopride, domperidone, levosulpiride and metoclopramide) have been exploited clinically for the management of motor disorders of the upper gastrointestinal tract, including functional dyspepsia, gastric stasis of various origins and emesis. The prokinetic effect of these drugs is mediated through the blockade of enteric (neuronal and muscular) inhibitory D2 receptors. The pharmacological profiles of the marketed compounds differ in terms of their molecular structure, affinity at D2 receptors, ability to interact with other receptor systems [5-hydroxytryptamine-3 (5-HT3) and 5-HT4 receptors for metoclopramide; 5-HT4 receptors for levosulpiride) and ability to permeate the blood-brain barrier (compared with the other compounds, domperidone does not easily cross the barrier). It has been suggested that the serotonergic (5-HT4) component of some antidopaminergic prokinetics may enhance their therapeutic efficacy in gastrointestinal disorders, such as functional dyspepsia and diabetic gastroparesis. The antagonism of central D2 receptors may lead to both therapeutic (e.g. anti-emetic effect due to D2 receptor blockade in the area postrema) and adverse (including hyperprolactinaemia and extrapyramidal dystonic reactions) effects. As the pituitary (as well as the area postrema) is outside the blood-brain barrier, hyperprolactinaemia is a side-effect occurring with all antidopaminergic prokinetics, although to different extents. Extrapyramidal reactions are most commonly observed with compounds crossing the blood-brain barrier, although with some differences amongst the various agents. Prokinetics with a high dissociation constant compared with that of dopamine at the D2 receptor (i.e. compounds that bind loosely to D2 receptors in the nigrostriatal pathway) elicit fewer extrapyramidal signs and symptoms. A knowledge of central and peripheral D2 receptor pharmacology can help the clinician to choose between the antidopaminergic prokinetics to obtain a more favourable risk/benefit ratio.
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PMID:Review article: clinical implications of enteric and central D2 receptor blockade by antidopaminergic gastrointestinal prokinetics. 1487 Dec 77

The therapeutic management of functional dyspepsia remains a major challenge for the gastroenterologist. Current therapies available are based on putative underlying pathophysiologic mechanisms, including gastric acid sensitivity, slow gastric emptying and Helicobacter pylori infection, but only a small proportion of patients achieve symptomatic benefit from these therapeutic approaches. Relatively novel mechanistic concepts under testing include impaired gastric accomodation, visceral hypersensitivity, and central nervous system dysfunction. Serotonergic modulators (e.g. the 5-HT4 agonist tegaserod, the 5-HT3 antagonist alosetron and the 5-HT1P agonist sumatriptan), CCK-1 antagonists (e.g. dexloxiglumide), opioid agonists (e.g. asimadoline), N-methyl-D-aspartate (NMDA) receptor antagonists (e.g dextromethorphan), neurokinin antagonists (e.g. talnetant), capsaicin-like agents and antidepressants are among the agents currently under investigation. It seems unlikely, however, that targeting a single mechanism with an individual drug will result in complete symptom remission in most cases.
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PMID:Functional dyspepsia: drugs for new (and old) therapeutic targets. 1532 10

The symptomatic management of irritable bowel syndrome (IBS) and functional dyspepsia, which often overlap, can be frustrating and difficult. Education and reassurance remain central for management although controlled trials are lacking. Psychological interventions may be useful in select patients but methodological inadequacies in clinical trials limit their interpretability. For symptom exacerbations, drug treatment is reasonable but no current treatment successfully targets the full symptom complex. Bulking agents are not of proven efficacy in IBS; they may improve constipation but worsen bloating and pain. Anticholinergics are of uncertain value in IBS. A meta-analysis of trials of smooth muscle relaxants for IBS has been reported to be positive but the quality of the trials included was poor. Antidepressants for IBS and functional dyspepsia appear to be efficacious based on the limited published evidence; both global symptoms and abdominal pain improve. Selective serotonin reuptake inhibitors (SSRIs) are of uncertain efficacy but anecdotally appear to be useful. Laxatives are not of proven efficacy in IBS. Loperamide improves diarrhea, but not abdominal pain in IBS. No drug is of proven efficacy for bloating. Acid suppression remains the mainstay of therapy for functional dyspepsia but the majority of patients do not have an adequate response. Promising drugs include new prokinetics for constipation-predominant IBS (e.g., tegaserod, a partial 5-HT4 agonist, prucalopride, a full 5-HT4 agonist, and dexloxiglumide, a cholecystokinin1 antagonist), agents for diarrhea-predominant IBS (e.g., 5-HT3 antagonists, alpha2 receptor agonists and corticotrophin receptor-1 antagonists), other visceral analgesics (e.g. tachykinin antagonists, opioid agonists) and in dyspepsia fundus relaxing agents (e.g., 5-HT1 agonists, tegaserod).
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PMID:New and emerging treatments for irritable bowel syndrome and functional dyspepsia. 1598 38

Functional gastrointestinal disorders are characterised by central and peripheral physiological changes, associated with psychological factors. Successful drug development has been hindered by lack of adequate characterisation of the nature of symptoms and their physiological and psychological correlates. Animal models of chronic stress are lacking. High levels of drug safety are now demanded for treating non-life threatening conditions. Once close to market, patient pressure groups, health care providers and insurers, government, and the internet can all influence a drug's success. Serotonin-modifying drugs have been the main recent focus of development, with mixed results. Cisapride has been withdrawn because of concerns related to QT prolongation and cardiac arrhythmias. The 5-HT3 antagonists have been developed on the questionable assumption that they modify visceral sensation in patients. Problems have arisen with alosetron being associated with ischaemic colitis and a high incidence of constipation. The 5-HT4 agonists have their major effect on inducing peristalsis, and may modify gut secretion and sensory function. Tegaserod and prucalopride show promise in patients with constipation and related symptoms. 5-HT1 agonists may play a role in treating functional dyspepsia, partly by improving impaired gastric accommodation to a meal. Antidepressants, often found to be clinically beneficial in these disorders, also affect serotonin metabolism. Past successes, such as loperamide or the somatostatin analogue octreotide, involved targeting end organ receptors influencing motor function or secretion. Modifying sensory function is much more challenging. Future research with novel compounds need to keep these recent lessons in mind.
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PMID:Pharmacological treatment of irritable bowel syndrome--from concept to sales. 1614 96


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