Influence of a 5HT1 receptor agonist on gastric accommodation and initial transpyloric flow in healthy subjects

Caffeine in the management of patients with headache

Caffeinated headache medications, either alone or in combination with other treatments, are widely used by patients with headache. Clinicians should be familiar with their use as well as the chemistry, pharmacology, dietary and medical sources, clinical benefits, and potential safety issues of caffeine. In this review, we consider the role of caffeine in the over-the-counter treatment of headache. The MEDLINE and Cochrane databases were searched by combining “caffeine” with the terms “headache,” “migraine,” and “tension-type.” Studies that were not placebo-controlled or that involved medications available only with a prescription, as well as those not assessing patients with migraine and/or tension-type headache (TTH), were excluded. Compared with analgesic medication alone, combinations of caffeine with analgesic medications, including acetaminophen, acetylsalicylic acid, and ibuprofen, showed significantly improved efficacy in the treatment of patients with TTH or migraine, with favorable tolerability in the vast majority of patients. The most common adverse events were nervousness (6.5%), nausea (4.3%), abdominal pain/discomfort (4.1%), and dizziness (3.2%). This review provides evidence for the role of caffeine as an analgesic adjuvant in the acute treatment of primary headache with over-the-counter drugs, caffeine doses of 130 mg enhance the efficacy of analgesics in TTH and doses of ≥100 mg enhance benefits in migraine. Additional studies are needed to assess the relationship between caffeine dosing and clinical benefits in patients with TTH and migraine.

Delayed absorption of many (paracetamol, aspirin, other NSAIDs and zolmitriptan) but not all (sumatriptan, rizatriptan) drugs during migraine attacks and most likely normal gastric emptying outside attacks. A review

Background In most pharmacokinetic studies, the oral absorption of drugs is impaired during migraine attacks but exceptions occur. A study on gastric emptying using gastric scintigraphy indicated that gastric stasis also occurs interictally in migraine. These studies were reviewed critically. Results In seven studies, mainly investigating NSAIDs and analgesics, the early absorption of the drugs during 112 migraine attacks was delayed. The absorption of sumatriptan is usual in therapeutic doses, and rizatriptan was normal during 131 migraine attacks. The interictal gastric stasis observed using gastric emptying scintigraphy (GES) with solids ( n = 13) could not be confirmed in a larger study ( n = 27) using the same method. Also gastric emptying measured with GES with liquids ( n = 7) and epigastric impedance ( n = 64) was normal outside migraine attacks. Conclusions and possible clinical implications Drug absorption is not generally impaired during migraine attacks. Gastric emptying is most likely normal in the majority of migraine patients outside attacks. Prokinetic and antiemetic drugs such as metoclopramide and domperidone should not be routinely combined with oral analgesics or oral triptans. If, however, nausea is severe or vomiting occurs, treatment with an antiemetic with proven efficacy on the nausea of migraine can be indicated.

Effects of L-tryptophan on gastric emptying evaluated by breath test in relation to gastric accommodation evaluated by Barostat in rats

Gastric emptying has been known to correlate the pyloric sphincter contractile function and distention-induced gastric relaxation (gastric accommodation). In the present study, the effects of L-tryptophan on the gastric emptying and accommodation were evaluated by breath test using [1-(13)C]acetic acid and Barostat study, respectively, in rats. L-Tryptophan significantly decreased Cmax and AUC120min and delayed Tmax, indicating the inhibition of gastric emptying. L-Tryptophan significantly enhanced the gastric accommodation. These findings show that L-tryptophan may inhibit the gastric emptying through the enhanced gastric accommodation. Therefore, L-tryptophan may be useful for the therapy of postprandial dyspepsia, especially for early satiety.

Influence of sumatriptan on gastric accommodation and on antral contraction in healthy subjects assessed by ultrasonography

BACKGROUND

Oral sumatriptan administration has been reported to delay gastric emptying after liquid meals. The aim of this study was to determine whether delayed gastric emptying is caused by enhanced gastric accommodation, impaired antral contractions, or both using ultrasonography.

METHODS

Ten healthy volunteers were enrolled in this randomized two-way crossover study. After overnight fasting, the subjects received the liquid meal 60 min after ingesting a 50 mg sumatriptan tablet with 50 mL of water or 50 mL of water alone (control). The cross-sectional area of the proximal stomach was measured in a supine position after every 100 mL. The frequency and amplitude of the antral contractions were measured in a slightly backward sitting position. The intragastric distribution of the liquid meal was assessed by calculating the proximal stomach/distal stomach ratio (prox/distal ratio).

KEY RESULTS

The cross-sectional area after drinking 100, 200, and 300 mL of the liquid meal (oral sumatriptan vs control) was 34.49 vs 15.11 cm(2) (P = 0.0051), 48.00 vs 30.61 cm(2) (P = 0.0166), and 58.67 vs 47.19 cm(2) (P = 0.0125), respectively. There was no significant difference in the amplitude of contractions, contraction cycle, motility index, and prox/distal ratio (97.15 vs 97.93%, P = 0.0745; 19.42 vs 19.5 s, P= 0.8590; and 887.58 vs 889.22, P = 0.5751; 9.75 vs 8.41, P = 0.8785; respectively).

CONCLUSIONS & INFERENCES

Oral sumatriptan administration enhanced gastric accommodation after the ingestion of liquid nutrients, but had no significant effect on antral contractions or intragastric distribution in healthy subjects.

Effect of sumatriptan on gastric emptying: A crossover study using the BreathID system

AIM: To determine the effect of oral sumatriptan on gastric emptying using a continuous ¹³C breath test (BreathID system).

METHODS: Ten healthy male volunteers participated in this randomized, 2-way crossover study. The subjects fasted overnight and were randomly assigned to receive a test meal (200 kcal/200 mL) 30 min after pre-medication with sumatriptan 50 mg (sumatriptan condition), or the test meal alone (control condition). Gastric emptying was monitored for 4 h after administration of the test meal by the ¹³C-acetic acid breath test performed continually using the BreathID system. Then, using Oridion Research Software (β version), the time taken for emptying of 50% of the labeled meal (T_1/2) similar to the scintigraphy lag time for 10% emptying of the labeled meal (T_lag), the gastric emptying coefficient (GEC), and the regression-estimated constants (β and κ) were calculated. The statistical significance of any differences in the parameters were analyzed using Wilcoxon’s signed-rank test.

RESULTS: In the sumatriptan condition, significant differences compared with the control condition were found in T_1/2 [median 131.84 min (range, 103.13-168.70) vs 120.27 min (89.61-138.25); P = 0.0016], T_lag [median 80.085 min (59.23-125.89) vs 61.11 min (39.86-87.05); P = 0.0125], and β [median 2.3374 (1.6407-3.8209) vs 2.0847 (1.4755-2.9269); P = 0.0284]. There were no significant differences in the GEC or κ between the 2 conditions.

CONCLUSION: This study showed that oral sumatriptan significantly delayed gastric emptying of a liquid meal.

Effects of clonidine and sumatriptan on postprandial gastric volume response, antral contraction waves and emptying: an MRI study

Gastric emptying (GE) may be driven by tonic contraction of the stomach ('pressure pump') or antral contraction waves (ACW) ('peristaltic pump'). The mechanism underlying GE was studied by contrasting the effects of clonidine (alpha(2)-adrenergic agonist) and sumatriptan (5-HT(1) agonist) on gastric function. Magnetic resonance imaging provided non-invasive assessment of gastric volume responses, ACW and GE in nine healthy volunteers. Investigations were performed in the right decubitus position after ingestion of 500 mL of 10% glucose (200 kcal) under placebo [0.9% NaCl intravenous (IV) and subcutaneous (SC)], clonidine [0.01 mg min(-1) IV, max 0.1 mg (placebo SC)] or sumatriptan [6 mg SC (placebo IV)]. Total gastric volume (TGV) and gastric content volume (GCV) were assessed every 5 min for 90 min, interspersed with dynamic scan sequences to measure ACW activity. During gastric filling, TGV increased with GCV indicating that meal volume dictates initial relaxation. Gastric contents volume continued to increase over the early postprandial period due to gastric secretion surpassing initial gastric emptying. Clonidine diminished this early increase in GCV, reduced gastric relaxation, decreased ACW frequency compared with placebo. Gastric emptying (GE) rate increased. Sumatriptan had no effect on initial GCV, but prolonged gastric relaxation and disrupted ACW activity. Gastric emptying was delayed. There was a negative correlation between gastric relaxation and GE rate (r(2 )=49%, P < 0.001), whereas the association between ACW frequency and GE rate was inconsistent and weak (r2=15%, P = 0.05). These findings support the hypothesis that nutrient liquid emptying is primarily driven by the 'pressure pump' mechanism.

Effect of the 5-HT3 receptor antagonist, ondansetron, on gastric size in dyspeptic patients with impaired gastric accommodation

BACKGROUND

A reduction of gastric accommodation after a meal has been documented in patients with idiopathic dyspepsia. In these patients the administration of a 5-HT3 receptor antagonist may reduce some of the dyspeptic symptoms; it is not clear however, whether these drugs influence gastric adaptation to distension as well.

AIM

To evaluate the effects of the 5-HT3 receptor antagonist, ondansetron, on gastric distension after a liquid meal in dyspeptic patients with reduced gastric accommodation.

METHODS

Before and after a 500 ml water load, gastric accommodation (area of the proximal and distal stomach) was evaluated using real-time ultrasonography in 21 idiopathic dyspepsia patients and 26 healthy controls. In dyspeptic patients, the test was repeated twice: after the administration of placebo and after ondansetron 8 mg i.v. (in both cases, 15 min prior to the water load). Secondary outcomes were epigastric pain, fullness and nausea as assessed by a visual analogue scale at basal and after ondansetron.

RESULTS

Fasting gastric size was similar in dyspeptic and controls. Compared with controls, dyspeptic patients showed a statistically significant smaller area of the proximal stomach (14.7+/-1.2 cm(2) vs. 18.6+/-1.4 cm(2), respectively; p=0.0247). In dyspeptic patients, gastric proximal and distal size did not change significantly following placebo, whereas after the administration of ondansetron the mean area of the proximal and distal stomach significantly increased (proximal stomach: 14.6+/-1.6 cm(2) placebo, 20.4+/-1.9 cm(2) ondansetron, p=0.0095; distal stomach: 8.9+/-0.9 placebo, 11.4+/-1.2cm(2) ondansetron, p=0.0409). Of the symptoms, only nausea was significantly reduced after ondansetron.

CONCLUSION

In dyspeptic patients with impaired gastric accommodation, ondansetron reverts gastric accommodation to within the range of controls.

Advanced imaging and visualization in gastrointestinal disorders

Advanced medical imaging and visualization has a strong impact on research and clinical decision making in gastroenterology. The aim of this paper is to show how imaging and visualization can disclose structural and functional abnormalities of the gastrointestinal (GI) tract. Imaging methods such as ultrasonography, magnetic resonance imaging (MRI), endoscopy, endosonography, and elastography will be outlined and visualization with Virtual Reality and haptic methods. Ultrasonography is a versatile method that can be used to evaluate antral contractility, gastric emptying, transpyloric flow, gastric configuration, intragastric distribution of meals, gastric accommodation and strain measurement of the gastric wall. Advanced methods for endoscopic ultrasound, three-dimensional (3D) ultrasound, and tissue Doppler (Strain Rate Imaging) provide detailed information of the GI tract. Food hypersensitivity reactions including gastrointestinal reactions due to food allergy can be visualized by ultrasonography and MRI. Development of multi-parametric and multi-modal imaging may increase diagnostic benefits and facilitate fusion of diagnostic and therapeutic imaging in the future.

Review article: a critical view on impaired accommodation as therapeutic target for functional dyspepsia

Several important pathophysiological mechanisms have been identified in functional dyspepsia, however a complete understanding of these mechanisms and beneficial therapeutic strategies are still lacking. Based on the currently available literature we aimed at providing a critical view on one of these pathophysiological mechanisms, impaired accommodation. Although impaired gastric accommodation is identified as a major pathophysiological mechanism, the clinical evidence supporting its role as an important therapeutic target is currently still lacking. Treatment with fundic relaxant drugs has shown conflicting results and has been rather disappointing in general. These negative findings could be explained by the fact that impaired fundic accommodation is part of a more complex disorder involving other regions of the proximal gut or by the increasing insight that central mechanisms may play an important role. Future studies of impaired accommodation should take these considerations into account.

Gastric accommodation assessed by ultrasonography

Gastric accommodation is important for the under-standing of the pathophysiology in functional dyspepsia and is also relevant for symptom generation in other disorders. The term gastric accommodation has at least three different meanings: The accommodation process, the accommodation reflex, and the accommodation response. The gastric accommodation process is a complex phenomenon that describes how the size of the gastric compartment changes in response to a meal. The electronic barostat is considered the gold standard in assessing gastric accommodation. Imaging methods, including MRI, SPECT, and ultrasonography may also be used, particularly in patients who are stress-responsive, e.g. functional dyspepsia patients, as a non-invasive and less stress-inducing method is favourable. Ultrasonography satisfies these criteria as it does not by itself distort the physiological response in stress-responsive individuals.

Role of cholecystokinin and central serotonergic receptors in functional dyspepsia

Symptoms of functional dyspepsia are characterized by upper abdominal discomfort or pain, early satiety, postprandial fullness, bloating, nausea and vomiting. It is a chronic disorder, with symptoms more than 3 mo per year, and no evidence of organic diseases. Dysfunctional motility, altered visceral sensation, and psychosocial factors have all been identified as major pathophysiological mechanisms. It is believed that these pathophysiological mechanisms interact to produce the observed symptoms. Dyspepsia has been categorized into three subgroups based on dominant symptoms. Dysmotility-like dyspepsia describes a subgroup of patients whose symptom complex is usually related to a gastric sensorimotor dysfunction. The brain-gut peptide cholecystokinin (CCK) and serotonin (5-HT) share certain physiological effects. Both have been shown to decrease gastric emptying and affect satiety. Furthermore the CCK induced anorexia depended on serotonergic functions probably acting via central pathways. We believe that abnormalities of central serotonergic receptors functioning together with a hyper responsiveness to CCK or their interactions may be responsible for the genesis of symptoms in functional dyspepsia (FD).

Influence of 5-HT1 receptor agonists on feline stomach relaxation

Sumatriptan is known for its stomach relaxing properties in both humans and cats, but the receptor involved has not been characterized. In a barostat study the intragastric volume was monitored in sedated cats at constant pressure. The maximum intragastric volume increase after subcutaneous or intravenous administration of saline or agonists was registered [mean (n=4-5)]. Sumatriptan (0.01-1 mg kg(-1)) induced a dose-dependent intragastric volume increase vs. saline (4-15 vs. 5 ml, respectively) that was sometimes accompanied by retching after 8-10 min. Pre-treatment with nitric oxide-synthase inhibitors and different 5-HT(1) receptor antagonists N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinyl-cyclohexanecarboxamide(WAY-100635), 2-methyl-4-(5-methyl-[1,2,4]oxadiazol-3-yl)-biphenyl-4-carboxylic-acid[4-methoxy-3-(4-methyl-piperazin-1-yl)-phenyl]amide(GR-127935), N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan-amide(5-HTP-DP) and 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine-HCl(NAN-190) did not affect the sumatriptan-induced effect. Alniditan (5-HT(1A/1D) receptor agonist) and flesinoxan (5-HT(1A) receptor agonist) did not induce significant intragastric volume changes. The 5-HT(1F) receptor agonists 5-hydroxy-3-(1-methylpiperidin-4-yl)-1H-indole(BRL-54443) and (R)-(+)-N-(3-dimethylamino-1,2,3,4-tetrahydro-9H-carbazol-6-yl)-4-fluorobenzamide(LY-344864; 0.003-3 mg kg(-1)) however induced a dose-dependent intragastric volume increase (6-36 and 5-26 ml, respectively), no retching was seen. Our results suggest that stimulation of 5-HT(1F) receptors induces feline stomach relaxation. Whether the sumatriptan-induced gastric relaxation in cats is due to interaction with 5-HT(1F) receptors could not be proven absolutely in view of the lack of selective 5-HT(1F) receptor antagonists.

Maximum tolerated volume in drinking tests with water and a nutritional beverage for the diagnosis of functional dyspepsia

AIM: Recently, drinking load tests with water or nutritional beverages have been proposed as diagnostic tools for functional dyspepsia (FD), therefore we sought to reproduce if these tests can discriminate between FD patients and controls in a Mexican population.

METHODS: Twenty FD-Rome II patients were matched by age and gender with 20 healthy controls. All underwent both drinking tests at a 15 mL/min rate, randomly, 7 d apart. Every 5 min within each test, four symptoms were evaluated (satiety, bloating, nausea and pain) by Likert scales. Maximum tolerated volume (MTV) was defined as the ingested volume when a score of 5 was reached for any symptom or when the test had to be stopped because the patients could not tolerate more volume. Sensitivity and specificity were analyzed.

RESULTS: FD patients had higher symptom scores for both tests compared to controls (water: t = 4.1, P = 0.001<0.01; Nutren^®: t = 5.2, P = 0.001<0.01). The MTV for water and Nutren^® were significantly lower in FD (water: 1014±288 vs 1749±275 mL; t = 7.9, P = 0.001<0.01; Nutren^®: 652±168 vs 1278±286 mL; t = 6.7, P = 0.001<0.01). With the volume tolerated by the controls, the percentile 10 was determined as the lower limit for tolerance. Sensitivity and specificity were 0.90, 0.95 for water and 0.95, 0.95 for Nutren^® tests.

CONCLUSION: A drinking test with water or a nutritional beverage can discriminate between FD patients and healthy subjects in Mexico, with high sensitivity and specificity. These tests could be used as objective, noninvasive, and safe diagnostic approaches for FD patients.

Assessment of gastric accommodation: overview and evaluation of current methods

Gastric accommodation is considered important in the pathophysiology of several upper gastrointestinal disorders including functional dyspepsia. The gold standard for its measurement is the barostat-balloon study which requires intubation. The aim was explore the reliability and performance characteristics of the techniques proposed for measurement of gastric accommodation. We undertook a literature search using MEDLINE with a broad range of key words. The accommodation reflex and its control are briefly described, based on human data. The performance characteristics of the intragastric barostat, transabdominal ultrasound, magnetic resonance imaging, single photon emission computed tomography, and satiation drinking tests are described. For each technique, we summarize the following: principle, validation studies, advantages, disadvantages, and potential applications. Three-dimensional methods to measure gastric volume non-invasively are promising and among the best validated to date. Simpler techniques would be of considerable appeal for clinical and research studies, but further validation is necessary before satiation drinking tests can be used as surrogates for more sophisticated measurements of gastric accommodation.

Diet, food intake, and disturbed physiology in the pathogenesis of symptoms in functional dyspepsia

Functional dyspepsia (FD) remains a relatively poorly characterized gastrointestinal disorder of unknown etiology that is frequently difficult to manage. A systematic review of the literature relating to food intake and FD is summarized here. Many patients with FD report symptoms after meal ingestion, including fullness, bloating, epigastric pain, nausea, and vomiting, and this has been interpreted as indicative of an underlying "motor disorder of the stomach or small intestine." Such hypotheses are, however, still largely unsubstantiated, and the data that do exist are inconclusive, particularly as few studies have directly examined the temporal relationships between dyspeptic symptoms, meal ingestion, and disordered gastric motility. Moreover, studies attempting to relate symptoms to specific disturbances in gastric motor function have, in most cases, not evaluated symptoms concurrently with the function test, and/or have used suboptimal symptom scoring to quantify symptoms. Furthermore, the term "early satiety" has been used loosely as a symptom, rather than a quantitative measure of food intake. Currently, the most widely accepted mechanism underlying FD is visceral hypersensitivity, which may contribute to both enhanced motor and symptomatic responses to food ingestion. However, the possible contribution of food and dietary habits to the induction and/or exacerbation of dyspeptic symptoms represents a relatively new area-despite frequent reports by patients that their symptoms are often related to food ingestion; this association has not been formally assessed. Dietary assessments have frequently implicated fatty foods in symptom induction, and these findings are supported by laboratory-based studies, particularly the demonstration that FD patients more often experience symptoms after intraduodenal infusions of fat, than glucose. Further studies into the potential role of dietary factors in the induction of dyspeptic symptom are required to establish whether dietary therapies have any place in the management of FD.

Treatment of Functional Dyspepsia

Because there is currently no universally effective treatment for functional dyspepsia, a stepwise approach is useful. The initial steps should include 1) making a firm clinical diagnosis and providing the patient with appropriate information and reassurance; 2) ascertaining the reason for referral/consultation, as this determines what the patient will regard as a satisfactory outcome; 3) informing the patient that there is no universally effective drug treatment; and 4) giving dietary and general lifestyle advice, such as ingestion of smaller, more frequent meals, a low-fat diet, avoidance of certain foods that may exacerbate symptoms, limiting coffee and alcohol intake, smoking cessation, and stress management techniques. If the initial approach does not provide a satisfactory outcome, the following approaches may be helpful. Psychologic treatment approaches, such as hypnotherapy and/or antidepressants, have shown very encouraging results in recent studies and deserve active consideration. In patients with uninvestigated dyspepsia, the "test and treat" strategy for Helicobacter pylori is a cost-effective approach. Prokinetics are of possible benefit in subjects with delayed gastric emptying; however, the relationship between improvement of gastric emptying and symptom alleviation is weak. Furthermore, it needs to be recognized that treatments directed at acid suppression are generally of little sustained benefit, and that there is ongoing controversy as to whether H. pylori eradication is of direct benefit.

Pharmacokinetics, pharmacodynamics, and safety of the 5-HT(1B/1D) agonist eletriptan following intravenous and oral administration

Four separate studies were conducted to examine the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of eletriptan, a 5-HT(1B/1D) receptor agonist being developed for the treatment of migraines, after oral and intravenous administration. Fifty-five males received oral (1.5-30 mg or 30-120 mg) or intravenous (1.67-50 microg/kg or 50-102 microg/kg) eletriptan in four double- and single-blind, placebo-controlled, ascending-dose crossover studies. The maximum plasma concentration (Cmax) and area under the concentration curve (AUC) appeared linear over all dose ranges, with an apparent terminal half-life of 4 to 5 hours. Clearance and volume of distribution remained constant with dose. The time to first occurrence of Cmax (tmax) for oral eletriptan was approximately 1 hour and was unaffected by dose. Comparison of AUC values suggested an absolute bioavailability of approximately 50%. A linear PK/PD model, fitted to the data, predicted small, transient elevations in diastolic blood pressure following eletriptan doses > or = 60 mg. These effects were considered unlikely to be clinically significant. Eletriptan was well tolerated, and treatment-related adverse events were mild to moderate and transient. These PK properties should result in eletriptan having a rapid onset and sustained duration of action in terms of migraine efficacy.

The proximal stomach and postprandial symptoms in functional dyspeptics

OBJECTIVES

It remains unclear whether postprandial symptom profiles in patients with visceral hypersensitivity and in those with impaired fundic accommodation differ. Therefore, we evaluated the postprandial symptoms in functional dyspepsia (FD) patients classified according to proximal stomach function. In addition, the effect of gastric relaxation induced by sumatriptan on postprandial symptoms was studied in FD patients with impaired fundic accommodation.

METHODS

Twenty-five healthy volunteers (HVs) and 44 FD patients filled out a disease-specific questionnaire (Nepean Dyspepsia Index) and underwent a gastric barostat study to evaluate visceral sensitivity, meal-induced fundic relaxation, and postprandial symptoms. Postprandial symptoms evoked by a drink test or reported during the barostat study were compared between FD patients subdivided according to the underlying pathophysiological mechanism. Finally, the effect of sumatriptan on postprandial symptoms evoked by a drink test was investigated in HVs and in FD patients with impaired fundic accommodation.

RESULTS

There was no clear relationship between any of the 15 Nepean Dyspepsia Index symptoms and proximal stomach function. Postprandial symptoms evoked during the barostat study or after the drink tests were significantly higher in FD patients than in HVs; however, no clear differences in symptom profile could be demonstrated between the different subclasses of FD. Sumatriptan did not affect the maximal ingested volume or the postprandial symptoms in HVs or FD patients after a drink test.

CONCLUSIONS

No clear relationship could be demonstrated between postprandial symptoms and proximal stomach function.

Impaired drinking capacity in patients with functional dyspepsia: relationship with proximal stomach function

BACKGROUND & AIMS

Impaired fundic accommodation to a meal and hypersensitivity to distention are increasingly recognized as important mechanisms underlying functional dyspepsia (FD). In the present study, we evaluated whether a drink test can predict such abnormalities and thus represent a noninvasive tool to study proximal stomach motor function.

METHODS

Healthy volunteers (HV), nonconsulters with mild dyspeptic symptoms (MS), and patients with FD filled out a disease-specific questionnaire and underwent a drink test with either water or with a high calorie fluid. The maximal ingested volume and the subsequent symptoms were meticulously recorded. In addition, all subjects underwent a gastric barostat study assessing meal-induced relaxation and sensation to distention.

RESULTS

Drinking capacity was not significantly related to any particular dyspeptic symptom. FD were able to consume less water (893 +/- 70 mL) and caloric liquid (767 +/- 50 mL) compared with HV (water, 1764 +/- 120 mL; caloric liquid, 1308 +/- 96 mL) or MS (water, 1645 +/- 120 mL; caloric liquid, 973 +/- 45 mL). Approximately half of the FD had an abnormal water or Nutridrink test compared with 9% of MS and 4% of HV. Furthermore, FD developed significantly more symptoms than MS or HV after both drink tests. The drinking capacity did not predict impaired fundic accommodation or visceral hypersensitivity.

CONCLUSIONS

FD, but not MS, have an impaired drinking capacity to both water and a nutrient liquid. The drinking capacity is not related to a specific dyspeptic symptom and does not predict proximal stomach motor function.

Gastric motor effects of triptans: open questions and future perspectives

Sumatriptan is a 5-HT1B/D receptor agonist of documented efficacy in relieving migraine and associated symptoms such as nausea and vomiting. In the past decade, several studies reported an important delay of gastric emptying induced by sumatriptan in healthy humans. The impact of this gastric motor effect of sumatriptan in migraineurs is difficult to predict: a further delay in gastric emptying could be detrimental (i.e. increased nausea and epigastric symptoms) in patients already having delayed gastric emptying. However, in patients with functional dyspepsia, sumatriptan is also reported to improve gastric accommodation to a meal and reduce perception of gastric distention, hence relieving epigastric symptoms. Thus, reduced visceral perception could be a mechanism involved in reducing nausea during a migraine attack. Paradoxically, sumatriptan is reported both to relieve the nausea of a migraine attack and to have nausea as a side effect. Although careful analysis of the time of onset of nausea may offer a clue as to the origin of this symptom, available data do not support definite conclusions, all the more so because the gastric motor effect of second-generation triptans are still unexplored. Taken together, the available evidence warrants further studies to clarify the following issues: first, the mechanism responsible for the gastric motor effect of sumatriptan [receptor subtype(s) involved; central vs peripheral mechanism]; secondly, the effects on gastric motility/visceral sensitivity of second-generation triptans (which are 5-HT1B/D receptor agonists) and more recent selective 5-HT1D receptor agonists (proposed as investigational antimigraine agents with less potential to induce coronary vasoconstriction through 5-HT1B receptors); finally, the possible use of drugs improving gastric accommodation to a meal in the management of those dyspeptic patients with impaired fundic relaxation/altered visceral sensitivity.

Nonulcer dyspepsia

New definitions of functional disorders in general and nonulcer dyspepsia in particular were published in the period of review. Although the definition of functional dyspepsia as persistent or recurrent unexplained upper abdominal pain or discomfort stayed essentially the same, new definitions of dyspepsia subgroups were introduced based on the predominant symptom; a reflux-like dyspepsia subgroup was not supported. It is hoped that these criteria, derived by a consensus among international experts in the field, will improve the reliability and the interpretability of future epidemiologic and interventional studies. A wide range of studies dealt with the role of putative etiological factors in functional bowel disorders including Helicobacter pylori, altered visceral sensation, or upper intestinal motility. Although eradication of H. pylori does not seem to relieve dyspepsia over placebo in recent studies of nonulcer dyspepsia, eradication of H. pylori has generally been advised because of suspected beneficial long-term effects (eg, treatment of misdiagnosed ulcer disease) that probably overweigh the potential risks.