Effects of octreotide and erythromycin on gastric myoelectrical and motor activities in patients with gastroparesis

The effect of single and repeated doses of rivastigmine on gastric myoelectric activity in experimental pigs

BACKGROUND

Rivastigmine is a pseudo-irreversible cholinesterase inhibitor used for therapy of Alzheimer's disease and non-Alzheimer dementia syndromes. In humans, rivastigmine can cause significant gastrointestinal side effects that can limit its clinical use. The aim of this study was to assess the impact of rivastigmine on gastric motor function by means of electrogastrography (EGG) in experimental pigs.

METHODS

Six experimental adult female pigs (Sus scrofa f. domestica, hybrids of Czech White and Landrace breeds; 3-month-old; mean weight 30.7 ± 1.2 kg) were enrolled into the study twice and created two experimental groups. In group A, a single intragastric dose of 6 mg rivastigmine hydrogen tartate was administered in the morning to fasting pigs before EGG recording. In group B, rivastigmine was administered to overnight fasting animals in a dietary bolus in the morning for 7 days (6 mg per day). On day 8, an intragastric dose of 12 mg rivastigmine was given in the morning to fasting pigs before EGG. EGG recording was accomplished by means of an EGG standalone system. Recordings from both groups were evaluated in dominant frequency and EGG power (areas of amplitudes).

RESULTS

In total, 1,980 one-minute EGG intervals were evaluated. In group A, basal EGG power (median 1290.5; interquartile range 736.5-2330 μV2) was significantly higher in comparison with the power of intervals T6 (882; 577-1375; p = 0.001) and T10 (992.5; 385-2859; p = 0.032). In group B, the dominant frequency increased significantly from basal values (1.97 ± 1.57 cycles per minute) to intervals T9 (3.26 ± 2.16; p < 0.001) and T10 (2.14 ± 1.16; p = 0.012), respectively. In group B, basal EGG power (median 1030.5; interquartile range 549-5093) was significantly higher in comparison with the power of intervals T7 (692.5; 434-1476; p = 0.002) and T8 (799; 435-1463 μV2; p = 0.004).

CONCLUSIONS

Both single as well as repeated intragastric administration of rivastigmine hydrogen tartrate caused a significant decrease of EGG power (areas of amplitudes) in experimental pigs. EGG power may serve as an indirect indicator of gastric motor competence. These findings might provide a possible explanation of rivastigmine-associated dyspepsia in humans.

Ameliorating effects of auricular electroacupuncture on rectal distention-induced gastric dysrhythmias in rats

Gastric slow waves (GSW) are known to regulate gastric motility and are impaired with rectal distention (RD). Electroacupuncture (EA) at body acupoints, such as ST 36, has been shown to improve gastric dysrhythmias; however, little is known about the possible effects of auricular electroacupuncture (AEA) on GSW. To study effects and possible mechanisms of AEA on RD-induced gastric dysrhythmias in rats, ten male Sprague-Dawley (SD) rats implanted with gastric serosal electrodes were studied in two different experiments in fed state. Four sessions were performed in experiment 1 as follows: control (RD, no stimulation), RD+AEA, RD+EA at body points and RD+sham AEA. Two sessions were included in experiment 2 to study mechanisms of AEA: RD + atropine and RD + atropine + AEA. It was found that 1) RD significantly decreased the percentage of normal GSW from 89.8 ± 3.5% to 76.0 ± 3.3% (P<0.05); 2) AEA increased the percentage of normal GSW during RD to 94.0 ± 2.1% (P<0.05 vs. RD) via a reduction in the percentages of tachygastria and arrhythmia (P<0.05 vs. RD); 3) atropine blocked the ameliorating effect of AEA on RD-induced gastric dysrhythmias. Our results demonstrated that RD induces gastric dysrhythmias in fed state in rats. AEA improves RD-induced gastric dysrhythmias via the vagal pathway. AEA may have a therapeutic potential in treating gastric dysrhythmias.

Technique of functional and motility test: how to perform antroduodenal manometry

Antroduodenal manometry is one of the methods to evaluate stomach and duodenal motility. This test is a valuable diagnostic tool for gastrointestinal motility disorders especially small intestinal pseudo-obstruction which is difficult to make definite diagnosis by clinical manifestations or radiologic findings. Manometric findings that have no evidence of mechanical obstruction and suggestive of pseudo-obstruction with neuropathy or myopathy can avoid unnecessary surgery and the treatment can be directly targeted. Moreover, among patients who have clinically suspected small intestinal pseudo-obstruction but with normal manometric findings, the alternative diagnosis including psychiatric disorder or other organic disease should be considered. The application of this test to the patients with functional gastrointestinal symptoms especially to find the association of motor abnormalities to the symptom has less impressive yield. Antroduodenal manometry is now readily available only in some tertiary care centers. The aim of this review is to describe the antroduodenal manometry technique, interpretation and clinical utility.

Prediction of octreotide efficacy by electrogastrography in the treatment of patients with esophageal variceal hemorrhage

Our aim is to investigate the significance of electrogastrography in the treatment of esophageal variceal hemorrhage with octreotide. Electrogastrography was performed in patients with esophageal variceal hemorrhage before and during the treatment consisting of various doses of octreotide (25 ug h(-1) group and 50 ug h(-1) group). The dominant power of electrogastrography and its relationship with the hemostatic efficacy of octreotide treatment were evaluated. Dominant power of electrogastrography decreased significantly during treatment with octreotide (P < 0.05). The reduction in the amplitude of dominant power in the 50 ug h(-1) group was significantly larger than in the 25 ug h(-1) group (P < 0.05), and it was correlated with hemostatic efficacy of octreotide treatment. We conclude that octreotide treatment in patients with esophageal variceal hemorrhage can result in a significant decrease of dominant power, which correlates with the hemostatic efficacy of octreotide, so the change of dominant power could be used as a predictor of evaluating the treatment efficacy of octreotide in esophageal variceal hemorrhage patients.

Electrogastrography in adults and children: the strength, pitfalls, and clinical significance of the cutaneous recording of the gastric electrical activity

Cutaneous electrogastrography (EGG) is a non-invasive technique to record gastric myoelectrical activity from the abdominal surface. Although the recent rapid increase in the development of electrocardiography, EGG still suffers from several limitations. Currently, computer analysis of EGG provides few reliable parameters, such as frequency and the percentage of normal and altered slow wave activity (bradygastria and tachygastria). New EGG hardware and software, along with an appropriate arrangement of abdominal electrodes, could detect the coupling of the gastric slow wave from the EGG. At present, EGG does not diagnose a specific disease, but it puts in evidence stomach motor dysfunctions in different pathological conditions as gastroparesis and functional dyspepsia. Despite the current pitfalls of EGG, a multitasking diagnostic protocol could involve the EGG and the (13)C-breath testing for the evaluation of the gastric emptying time-along with validated gastrointestinal questionnaires and biochemical evaluations of the main gastrointestinal peptides-to identify dyspeptic subgroups. The present review tries to report the state of the art about the pathophysiological background of the gastric electrical activity, the recording and processing methodology of the EGG with particular attention to multichannel recording, and the possible clinical application of the EGG in adult and children.

Electrogastrography associated with symptomatic changes after prokinetic drug treatment for functional dyspepsia

AIM: To evaluate the effect of prokinetic drugs on electrogastrography (EGG) parameters according to symptomatic changes in patients with functional dyspepsia (FD).

METHODS: Seventy-four patients with FD were prospectively enrolled in this study between December 2006 and December 2010. We surveyed the patients using a questionnaire on dyspeptic symptoms before and after an 8-wk course of prokinetic drug treatment. We also measured cutaneous pre-prandial and post-prandial EGG recordings including percentage of gastric waves (normogastria, bradygastria, tachygastria), dominant frequency (DF), dominant power (DP), dominant frequency instability coefficient (DFIC), dominant power instability coefficient (DPIC), and the ratio of post-prandial to fasting in DP before and after the 8-wk course of prokinetic drug treatment.

RESULTS: Fifty-two patients (70%) achieved symptomatic improvement after prokinetic drug treatment. Patients who had normal gastric slow waves showed symptom improvement group after treatment. Post-prandial DF showed a downward trend in the symptom improvement group, especially in the itopride group. Post-prandial DP was increased regardless of symptom improvement, especially in the itopride group and mosapride group. Post-prandial DFIC and DPIC in the symptom improvement group were significantly increased after the treatment. The EGG power ratio was increased after treatment in the symptom improvement group (0.50 ± 0.70 vs 0.93 ± 1.77, P = 0.002), especially in the itopride and levosulpiride groups.

CONCLUSION: Prokinetics could improve the symptoms of FD by regulating gastric myoelectrical activity, and EGG could be a useful tool in evaluating the effects of various prokinetics.

Effect of amoxicillin/clavulanate on gastrointestinal motility in children

AIM

The aim of the present study was to evaluate the effect of amoxicillin/clavulanate (A/C) on gastrointestinal motility.

METHODS

Twenty consecutive pediatric patients referred for antroduodenal manometry received 20 mg/kg of A/C into the small bowel lumen. In 10 patients (group A), A/C was given 1 hour after and in 10 (group B), 1 hour before ingestion of a meal. Characteristics of the migrating motor complex, including presence, frequency, amplitude, and propagation of duodenal phase III and phase I duration and phase II motility index (MI), were evaluated 30 minutes before and after A/C administration.

RESULTS

There were no statistically significant differences in age and sex between the 2 groups. Manometry studies were considered normal in 8 patients in each group. In group A, 2 patients developed duodenal phase III after receiving A/C, and no significant difference was found in the MI before and after the drug administration. In group B, 9 patients developed duodenal phase III (P <0.05 vs group A). All phase III occurred within a few minutes from the medication administration. Most duodenal phase III contractions were preceded by an antral component during fasting but never after the medication was administered in either of the 2 groups (P<0.001 vs fasting). In group B, the duration of duodenal phase I was shorter after drug administration (P<0.05). There was no significant difference in duodenal phase II MI before and after A/C administration for the 2 study groups.

CONCLUSIONS

In children, administration of A/C directly into the small bowel before a meal induces phase III-type contractions in the duodenum, with characteristics similar to those present in the fasting state. These data suggest the possible use of A/C as a prokinetic agent. Further studies are needed to clarify its specific mechanism of action and the group of patients most likely to benefit from its use.

New tools in the treatment of motility disorders in children

Gastrointestinal motility disorders can develop in neurologically impaired children and those with congenital malformations of the gut. It is characterized by moderate to severe abdominal pain, vomiting, and failure to thrive. Antral dysmotility after fundoplication and increased sympathetic over activity are 2 factors associated with this condition that make it difficult to treat. This paper proposes a management strategy using metoclopramide, celiac plexus blockade, and thoracic splanchnectomy. It reviews our experience with 11 patients.

Effects of Somatostatin Prophylaxis after Pylorus-preserving Pancreaticoduodenectomy: Increased Delayed Gastric Emptying and Reduced Plasma Motilin

Somatostatin inhibits gastroenteropancreatic exocrine secretion and is often used after pancreaticoduodenectomy to reduce pancreatic secretion to minimize tissue damage and pancreatic stump complications. Because our earlier clinical work saw a major increase in delayed gastric emptying (DGE) with somatostatin prophylaxis after pylorus-preserving pancreaticoduodenectomy (PPPD), this small-group study was designed to confirm or disprove that observation. From August 1997 to December 2000, a total of 23 post-PPPD patients were randomized to receive somatostatin prophylaxis [somatostain (+)] (n = 11) or not [somatostatin] (-) (n = 12). The incidence of DGE, scintographic solid-phase emptying results on day 14 postoperatively, and sequential fasting plasma motilin levels were compared, as motilin levels are related to both gastric motility and somatostatin levels. The somatostatin(+) group exhibited greatly increased patient complaints of DGE: 9 of 11 (82%) versus 3 of 12 (25%) in the somatostatin(-) group. Radiologic scintography showed somatostatin prophylaxis prolonged the half-time (T(1/2)) of solid-phase emptying: 144.5 +/- 51.4 minutes for somatostatin(+) versus 89.0 +/- 59.9 minutes for somatostatin(-) (p < 0.001). Comparing pre-PPPD and post-PPPD plasma motilin levels prior to somatostatin infusion, motilin decreased 80% in reaction to the surgery. For somatostatin(-) patients, motilin levels oscillated, or "rang," postoperatively, reaching a higher level on day 3, declined to a new record minimum on day 7, and by day 21 were 50% of the original and the slope of the recovery curve was increasing well. In somatostatin(+) patients the same ringing pattern was observed but decreased with motilin levels 30% to 70% lower than in the somatostatin(-) patients. By day 21 somatostatin(+) motilin levels were recovering but still only 20% original levels, and the slope of the recovery curve was not optimistic. On postoperative day 14 the plasma motilin levels (below approximately 6 bg/ml) correlated strongly with DGE for both groups. Despite the small sample size, the results indicated that (1) somatostatin prophylaxis significantly decreases fasting plasma motilin; (2) somatostatin prophylaxis produces lingering suppression of plasma motilin; (3) PPPD surgery itself significantly reduces fasting motilin levels with recovery to 50% normal at day 21; (4) the mechanism of somatostatin-induced DGE seems related to reduced fasting plasma motilin levels.

Electrogastrography: basic knowledge, recording, processing and its clinical applications

The slow wave (SW) of the gastrointestinal (GI) tract mainly functions to trigger the onset of spike to elicit smooth muscle contraction, which provides the essential power of motility. Smooth muscle myogenic control activity or SW is believed to originate in the interstitial cells of Cajal (ICC). The electrical coupling promotes interaction between muscle cells, and ICC additionally contribute to SW rhythmicity. Stomach SW originates in the proximal body showing the continuous rhythmic change in the membrane potential and propagates normally to the distal antrum with a regular rhythm of approximately 3 c.p.m. A technique using electrodes positioned on the abdominal skin to pick up stomach rhythmic SW refers to electrogastrography (EGG). The stomach SW amplitude is very weak, while many visceral organs also produce rhythmic electricities, for example heartbeat, respiration, other organs of the GI tract and even body movements. Thus noise other than SW should be filtered out during the recording, while motion artifacts are visually examined and deleted. Finally, the best signal among all recordings is selected to compute EGG parameters based on spectral analysis. The latter is done not only to tranform frequency domain to time domain but also to provide information of time variability in frequency. Obtained EGG parameters include dominant frequency/power, % normal rhythm, % bradygastria, % tachygastria, instability coefficient and power ratio. Clinical experience in EGG has been markedly accumulated since its rapid evolution. In contrast, lack of standardized methodology in terms of electrode positions, recording periods, test meals, analytic software and normal reference values makes the significance of EGG recording controversial. Unlike imaging or manometrical studies, stomach motility disorders are not diagnosed based only on abnormal EGG parameters. Limitations of EGG recording, processing, computation, acceptable normal parameters, technique and reading should be known to conduct subjective assessments when EGG is used to resolve stomach dysfunction. Understanding basic SW physiology, recording methodology and indications may open EGG as a new domain to approach the stomach motor dysfunction.

Current pharmacological treatment of gastroparesis

The aetiology of gastroparesis differs between children and adults. During childhood, gastroparesis is quite rare, and is mostly seen in preterm infants, with either immaturity of the gastrointestinal tract, or when allergic to cow's milk protein. Acute, delayed gastric emptying may be observed following viral infections. In adults, most patients with gastroparesis are either idiopathic or of diabetic origin. As a consequence, approaches in the treatment of children and adults differ. Metoclopramide, domperidone, cisapride and erythromycin have all been studied. Evidence for benefit is strongest for the latter two drugs, although most studies have methodological shortcomings. From a paediatric perspective, it seems astonishing that more trials with erythromycin analogues have not been performed, as the few data available suggests that these analogues are more powerful, without the side effects of long-term, low-dose administration of antibiotics. Gastric electrical stimulation seems the most promising therapeutic option available at present.

Inhibitory effects of stress on postprandial gastric myoelectrical activity and vagal tone in healthy subjects

The aim was to investigate gastric myoelectrical activity (GMA) and vagal activity in response to stress. The study was performed in 10 healthy subjects in three sessions (control, relaxation and stress). The control session was composed of 30-min recordings before and 30-min recordings after a test meal. The protocol of two other sessions was similar except that the fasting recording was extended to 60 min and the subjects were continuously watching a horror movie (stress) or guided meditation tape (relaxation) after the 30-min baseline. GMA was recorded using electrogastrography and heart rate variability (HRV) was derived from the electrocardiogram. Meal resulted in a postprandial increase in the dominant frequency (2.91 cpm vs 3.17 cpm, P < 0.007), dominant power (30.0 dB vs 32.5 dB, P < 0.05), and percentage of normal slow waves (79.8%vs 87.4%, P = 0.09). Similar responses were found in the relaxation session. Stress inhibited all these normal postprandial response and reduced the regularity of gastric slow waves (82.0%vs 66.0%, P < 0.01). In addition, spectral analysis of the HRV demonstrated an inhibition of postprandial vagal activity and an increase of postprandial sympathetic activity with stress. Stress has an inhibitory effect on postprandial GMA and this may involve both vagal and sympathetic pathway.

Current concepts in diabetic gastroparesis

Diabetic gastroparesis is a common and debilitating condition affecting millions of patients with diabetes mellitus worldwide. Although gastroparesis in diabetes has been known clinically for more than 50 years, treatment options remain very limited. Until recently, the scientific literature has offered few clues regarding the precise aetiology of gastric dysfunction in diabetes.Up to 50% of patients with diabetes may experience postprandial abdominal pain, nausea, vomiting and bloating secondary to gastric dysfunction. There is no clear association between length of disease and the onset of delayed gastric emptying. Gastroparesis affects both type 1 (insulin dependent) and type 2 (non- insulin dependent) forms of diabetes. Diagnosis requires identifying the proper symptom complex, while excluding other entities (peptic ulcer disease, rheumatological diseases, medication effects). The diagnosis of gastroparesis may be confirmed by demonstrating gastric emptying delay during a 4-hour scintigraphic study. Treatment options are limited and rely on dietary modifications, judicious use of available pharmacological agents, and occasionally surgical or endoscopic placement of gastrostomies or jejunostomies. Gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation. Current pharmacological agents for treating gastroparesis include metoclopramide, erythromycin, cisapride (only available via a company-sponsored programme) and domperidone (not US FDA approved). All of these drugs act as promotility agents that increase the number or the intensity of gastric contractions. These medications are not uniformly effective and all have adverse effects that limit their use. Cisapride has been removed from the open market as a result of over 200 reported cases of cardiac toxicity attributed to its use. Unfortunately, there is a paucity of clinical studies that clearly define the efficacy of these agents in diabetic gastroparesis and there are no studies that compare these drugs to each other. The molecular pathophysiology of diabetic gastroparesis is unknown, limiting the development of rational therapies. New studies, primarily in animals, point to a defect in the enteric nervous system as a major molecular cause of abnormal gastric motility in diabetes. This defect is characterised by a loss of nitric oxide signals from nerves to muscles in the gut resulting in delayed gastric emptying. Novel therapies designed to augment nitric oxide signalling are being studied.

Current concepts in diabetic gastroparesis

Diabetic gastroparesis is a common and debilitating condition affecting millions of patients with diabetes mellitus worldwide. Although gastroparesis in diabetes has been known clinically for more than 50 years, treatment options remain very limited. Until recently, the scientific literature has offered few clues regarding the precise aetiology of gastric dysfunction in diabetes.Up to 50% of patients with diabetes may experience postprandial abdominal pain, nausea, vomiting and bloating secondary to gastric dysfunction. There is no clear association between length of disease and the onset of delayed gastric emptying. Gastroparesis affects both type 1 (insulin dependent) and type 2 (non- insulin dependent) forms of diabetes. Diagnosis requires identifying the proper symptom complex, while excluding other entities (peptic ulcer disease, rheumatological diseases, medication effects). The diagnosis of gastroparesis may be confirmed by demonstrating gastric emptying delay during a 4-hour scintigraphic study. Treatment options are limited and rely on dietary modifications, judicious use of available pharmacological agents, and occasionally surgical or endoscopic placement of gastrostomies or jejunostomies. Gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation. Current pharmacological agents for treating gastroparesis include metoclopramide, erythromycin, cisapride (only available via a company-sponsored programme) and domperidone (not US FDA approved). All of these drugs act as promotility agents that increase the number or the intensity of gastric contractions. These medications are not uniformly effective and all have adverse effects that limit their use. Cisapride has been removed from the open market as a result of over 200 reported cases of cardiac toxicity attributed to its use. Unfortunately, there is a paucity of clinical studies that clearly define the efficacy of these agents in diabetic gastroparesis and there are no studies that compare these drugs to each other. The molecular pathophysiology of diabetic gastroparesis is unknown, limiting the development of rational therapies. New studies, primarily in animals, point to a defect in the enteric nervous system as a major molecular cause of abnormal gastric motility in diabetes. This defect is characterised by a loss of nitric oxide signals from nerves to muscles in the gut resulting in delayed gastric emptying. Novel therapies designed to augment nitric oxide signalling are being studied.

Octreotide enhances the accelerating effect of erythromycin on gastric emptying in healthy subjects

BACKGROUND

Erythromycin exhibits gastrokinetic properties through cholinergic pathways. Reports regarding the action of octreotide on gastric emptying are conflicting.

AIM

: To assess: (i) the hypothesis that serotonin receptors are involved in the accelerating effect of erythromycin on gastric emptying; and (ii) any modification of the gastrokinetic action of erythromycin induced by octreotide.

SUBJECTS AND METHODS

Gastric emptying of a standard meal was estimated in 20 healthy subjects by scintigraphy on three different occasions in a double-blind, placebo-controlled manner and in random order: (i) after placebo; (ii) after 200 mg of intravenous erythromycin; and (iii) after 200 mg of intravenous erythromycin following pre-treatment with either 4 mg of intravenous ondansetron (10 subjects) or 50 micro g octreotide.

RESULTS

Erythromycin significantly accelerated gastric emptying in all subjects by abolishing the lag phase. Pre-treatment with ondansetron abolished the accelerating effect of erythromycin by restoring the emptying times to placebo levels. Octreotide significantly enhanced the accelerating effect of erythromycin by reducing both the lag and post-lag phases of gastric emptying.

CONCLUSIONS

Serotonin receptors are involved in the accelerating effect of erythromycin on gastric emptying. This effect seems to be enhanced by pre-treatment with octreotide, possibly as a result of the modification of the gastrointestinal hormonal environment.

Is there a one-to-one correlation between gastric emptying of liquids and gastric myoelectrical or motor activity in dogs?

The aim of this study was to investigate the correlation of gastric emptying with gastric myoelectrical activity recorded from internal serosal electrodes and with gastric motility measured from strain gauges. The study was performed in eight healthy dogs chronically implanted with four pairs of electrodes and two strain gauges on the gastric serosa and equipped with a duodenal fistula for the assessment of gastric emptying. Each dog was fed four liquid test meals on four separate days with identical calories (320 kcal) and volume (473 ml). A correlation was found between gastric emptying and the energy of contraction in the frequency band of 3.75-7.50 cycles/min during the first 30 min after the meal (r = 0.46, P < 0.05). While none of the parameters of gastric myoelectrical activity was correlated with gastric emptying, two major parameters, percentage of regular gastric slow waves and percentage of slow-wave coupling, were found to be associated with delayed gastric emptying. A significant correlation was found between the frequency of gastric slow waves and that of the contractions in both fasting (r = 0.83, P < 0.001) and fed state (r = 0.70, P < 0.001 at 30 min, r = 0.86, P < 0.001 at 60 min). It was concluded that gastric emptying is correlated with the strength of gastric contractions in a frequency range identical to that of the gastric slow waves, and there is no one-to-one correlation between gastric emptying of liquids and any parameters of gastric myoelectrical activity. However, major parameters of gastric myoelectrical activity are associated with gastric emptying.

Effects of low doses of erythromycin on the 13C Spirulina platensis gastric emptying breath test and electrogastrogram: a controlled study in healthy volunteers

OBJECTIVE

Electrogastrography and stable isotope gastric emptying breath tests (GEBTs) are relatively simple, noninvasive tests of gastric motor function that may be useful in monitoring the effects of therapeutic interventions. It was our primary objective to examine the effects of low dose i.v. erythromycin on the results of the 13C Spirulina platensis GEBT and electrogastrography. We were also interested in evaluating the reproducibility of these tests.

METHODS

In 10 healthy subjects (five female, ages 23-37 yr), we simultaneously performed the GEBT, using a prepackaged meal (340 kcal), and electrogastrography on each of four different occasions separated by at least 1 wk. After performance of baseline studies, they were repeated in random order after the infusion of 50 mg of erythromycin (Er50), 100 mg erythromycin (Er100), and a placebo (saline). Breath samples were obtained at baseline and at 75, 90, and 180 min after the meal and T1/2 and Tlag calculated. Electrogastrography recordings began 30 min before the test meal and continued for 2 h after the meal.

RESULTS

Baseline and placebo T1/2 and Tlag were similar. Er50 resulted in a modest acceleration of gastric emptying (T1/2 Er50 vs baseline vs placebo = 104.0 vs 132.7 vs 125.5 min) and reduction in lag time (Tlag Er50 vs baseline vs placebo = 47.2 vs 61.5 vs 56.2 min). A similar decrease was seen in response to Er100. The baseline and placebo fasting and fed electrogastrography parameters were similar. After infusion of Er100, the percentage of normal slow waves in the first postprandial hour decreased relative to baseline and placebo (percent normogastria Er100 vs baseline vs placebo = 64.1+/-7.5 vs 82.4+/-6.4 vs 79.7+/-5.5). This corresponded with an increase in percent tachygastria during the same period and an overall decrease in the mean dominant frequency. Similar but less striking changes were seen after administration of Er50. Replicate GEBTs showed a high degree of reproducibility both within and between individuals for T1/2 and Tlag. In contrast, replicate electrogastrograms revealed moderate to high variability for all parameters except the dominant frequency.

CONCLUSION

The stable isotope GEBT utilizing 13C S. platensis demonstrates responsiveness to the prokinetic effects of low dose i.v. erythromycin and good reproducibility.

Electrogastrography: a non-invasive measurement of gastric function

BACKGROUND

Electrogastrography (EGG) is the non-invasive measurement of gastric electrical activity. With the development of modern technology, improved recording and automated analysis, it is a reliable and accurate technique for the measurement of gastric myoelectrical activity providing information about the frequency and regularity of the gastric slow wave.

AIM

The aim of this report is to evaluate its role in clinical practice.

METHODS

The literature is reviewed and its role investigated.

RESULTS

EGG has been successfully used in the investigation of gastroparesis, non-ulcer dyspepsia (NUD), gastric emptying (GE) disorders and diabetes mellitus (DM). EGG also provides an insight into the effect of medications on gastric function, e.g. edrophonium, cisapride, erythromycin and proton-pump inhibitors (PPI).

CONCLUSIONS

EGG has a developing role in the assessment of gastric dysfunction and on the effect of medical treatment. The effect of surgery and anaesthesia on gastric myoelectric activity is less clear.

The effect of erythromycin on human esophageal motility is mediated by serotonin receptors

OBJECTIVE

Erythromycin exhibits prokinetic properties. The drug enhances esophageal and gastric motility by acting as a motilin agonist and promoting acetylocholine release. 5-HT3 receptors are involved in the spontaneously occurring migrating motor complex and the effect of erythromycin on antral motility in dogs. The aim of the study was to investigate the hypothesis that 5-HT3 receptors are also involved in the action of erythromycin on the human esophagus.

METHODS

A total of 18 healthy volunteers underwent standard esophageal manometry on three different occasions in a double-blind, placebo-controlled, randomized manner, as follows: 1) after placebo, 2) after 200 mg of erythromycin i.v., and 3) after 200 mg of i.v. erythromycin subsequent to pretreatment with either 4 mg of i. v. ondansetron (serotonin receptor antagonist) (10 subjects) or 12 microg/kg of i.v. atropine (8 subjects).

RESULTS

Erythromycin significantly increased a) the amplitude of peristalsis at 5 cm (from 87 +/- 19 mm Hg to 108 +/- 26 mm Hg; p = 0.0007), 10 cm (from 72 +/- 24 mm Hg to 81 +/- 26 mm Hg; p = 0.016), and 15 cm (from 47 +/- 15 mm Hg to 55 +/- 17 mm Hg; p = 0.014) proximal to LES, b) the duration of peristalsis at 5 cm (from 4.5 +/- 0.9 s to 5.7 +/- 1.2 s; p < 0.0001) and 10 cm (from 4.1 +/- 1 s to 4.9 +/- 1 s; p < 0.0001) proximal to the LES and c) the strength of peristalsis at 5 cm proximal to the LES (from 180 +/- 49 mm Hg x s to 276 +/- 100 mm Hg x s; p < 0.0001), and decreased the velocity of peristalsis at distal esophagus (from 4.1 +/- 1 cm/s to 3.8 +/- 0.9 cm/s; p = 0.03). In addition, erythromycin significantly increased the resting pressure of the LES (from 36 +/- 10 mm Hg to 44 +/- 12 mm Hg; p = 0.002). Pretreatment with ondansetron totally reversed all of the effects of erythromycin to the placebo state. Pretreatment with atropine not only prevented the effects of erythromycin, but it reduced the amplitude and strength of peristalsis at the distal esophagus at significantly lower levels than after placebo.

CONCLUSIONS

Erythromycin exerts its prokinetic action on the lower esophagus by stimulating cholinergic pathways. This action includes not only an increase in LES pressure, but significant increases in the amplitude and duration of esophageal peristalsis, as well. 5-HT3 receptors are also involved in this process.

Hyperglycaemia attenuates erythromycin-induced acceleration of solid-phase gastric emptying in idiopathic and diabetic gastroparesis

BACKGROUND

Erythromycin has recently been found to be a gastrointestinal prokinetic agent in humans. Acute hyperglycaemia has been associated with delayed gastric emptying in both healthy controls and diabetic patients. Our aim was to investigate in gastroparetic patients (diabetics and idiopathics) whether hyperglycaemia, per se, reduces gastric motility during erythromycin-induced acceleration of gastric emptying of solids.

METHODS

In 12 gastroparetic patients, 6 diabetics and 6 idiopathics, gastric emptying of solids was measured scintigraphically after giving placebo in normoglycaemia (5-8.9 mmol/l glucose) or 200 mg erythromycin lactobionate intravenously in normo- or hyperglycaemia (16-19 mmol/l glucose) induced by intravenous glucose infusion in random order on separate days.

RESULTS

Erythromycin in normoglycaemia accelerated solids gastric emptying compared with placebo in all patients by abolishing the lag-phase duration and by decreasing the retained percentage of a meal in the stomach at 120 and 150 min (14.5% +/- 5.3% versus 88.4% +/- 10.6% and 3.5% +/- 2.1% versus 70.1% +/- 15.4%, respectively) (P < 0.001). The retained isotopic percentage in the stomach after erythromycin in induced hyperglycaemia compared with erythromycin in normoglycaemia, at 120 and 150 min, was increased (51.9% +/- 9.8% versus 14.5% +/- 5.3%, and 24.5% +/- 5.9% versus 3.5% +/- 2.1%, respectively) (P < 0.001) but was decreased in comparison with placebo (P < 0.001). A significantly increased percentage of isotope was retained in the stomach of the diabetic patients at 120 and 150 min, compared with the idiopathics, only after giving erythromycin in the hyperglycaemic condition (57.6% +/- 8.7% versus 46.1% +/- 7.6% (P = 0.036) and 27.8% +/- 5.7% versus 21.1 +/- 4.4% (P = 0.040), respectively).

CONCLUSIONS

Hyperglycaemia attenuates erythromycin-induced acceleration of solid-phase gastric emptying in idiopathic and diabetic gastroparesis and increases the retained isotopic meal in the stomach. Hyperglycaemia reduces gastric motility more in the diabetic patients with gastroparesis than in idiopathic patients.