Cholinergic effects on human gastric motility

BACKGROUND: Cholinergic regulation of chronotropic (frequency) and inotropic (force) aspects of antral contractility and how these impact on gastric emptying are not well delineated. AIMS: To determine the effects of cholinergic stimulation and inhibition on myoelectric, contractile, and emptying parameters of gastric motility. METHODS: Ten normal subjects underwent three studies each, using simultaneous electrogastrography (EGG), antroduodenal manometry, and gastric emptying with dynamic antral scintigraphy (DAS). After 30 minutes of baseline fasting manometry and EGG, subjects received saline intravenously, atropine (0.6 mg then 0.25 mg/hour intravenously), or bethanechol (5 mg subcutaneously). This was followed by another 30 minutes' recording and by three hours of postprandial recording after ingestion of a technetium-99m labelled solid meal. RESULTS: During fasting, atropine decreased, whereas bethanechol increased, the antral manometric motility index and EGG power. Postprandially, atropine decreased the amplitude of antral contractions by DAS, decreased the postprandial antral manometric motility index, and slowed gastric emptying. Atropine caused a slight increase in postprandial frequency of antral contractions by DAS and gastric myoelectrical activity by EGG. Bethanechol slightly increased the amplitude, but slightly decreased the frequency of antral contractions by DAS and decreased the frequency of gastric myoelectrical activity by EGG, with no significant increase in the motility index or gastric emptying. CONCLUSIONS: Cholinergic antagonism with atropine reduces antral contractility and slows gastric emptying. Cholinergic stimulation with bethanechol increases antral contractility, but decreases the frequency of antral contractions, without altering the antral motility index or gastric emptying.     

Gastric myoelectrical activity and gastric emptying in patients with functional dyspepsia

OBJECTIVES: The aims of this study were to investigate gastric myoelectrical activity and gastric emptying (GE) and their relationship in patients with functional dyspepsia. METHODS: The study was conducted in 15 healthy volunteers (six women, nine men, mean age: 42 yr) and 15 patients (13 women, two men, mean age: 43 yr) with functional dyspepsia. Gastric myoelectrical activity was recorded using cutaneous electrogastrography (EGG) for 30 min in the fasting state and for 120 min simultaneously with GE monitoring after an isotope-labeled solid meal. The anterior/posterior images of the stomach were taken using a technetium scanner immediately after eating, and then at 1, 2, and 4 h to determine the percentage of gastric retention. The dominant frequency of the EGG, the change of the postprandial EGG peak power (deltaP), and the percentage of normal 2-4 cycles/min (cpm) slow waves during each recording session were calculated and compared between the patients and healthy subjects. RESULTS: The patients had a significantly lower mean percentage of 2-4 cpm slow waves, both in the fed state and in the fasting state, than did healthy subjects. Compared to the EGG in the fasting state, a significant increase of the EGG dominant frequency in the fed state was observed in healthy subjects but not in the patients. The mean postprandial EGG power increase in the patients was substantially less than in the healthy subjects during the first postprandial hour but similar during the second postprandial hour. The mean percentage of gastric retention in patients is substantially higher than in the healthy subjects, both at 2 h after eating and at 4 h after eating. Of 15 patients, nine (60%) had delayed GE (gastric retention at 2 h >50%) and 10 (66%) had abnormal EGGs (percentage of 2-4 cpm <70% and/or deltaP < 0). Eight of these 10 patients (80%) with abnormal EGGs had delayed GE. CONCLUSIONS: A high proportion of adult patients (60%) with functional dyspepsia have abnormally slow GE and abnormalities in gastric myoelectrical activity.     

Inhibitory effects of cholecystokinin on postprandial gastric myoelectrical activity

While a number of studies have investigated the effects of cholecystokinin (CCK) on gastrointestinal motility, little is known on the effects of CCK on gastric myoelectrical activity, which regulates gastric motility. The aim of this study was to investigate the effects of intravenous infusion of CCK-8 on gastric myoelectrical activity in normal humans. Gastric myoelectrical activity was measured in 10 healthy subjects with a noninvasive electrogastrographic technique by placing abdominal electrodes on the epigastric area. Two study sessions were performed in each subject on two separate days with double-blinded infusion of either saline or CCK (24 pmol/kg/hr). The procedure for each session was as follows: (A) 30-min baseline fasting electrogastrogram (EGG); (B) start infusion, another 30-min EGG; (C) give meal, 60-min EGG; and (D) stop infusion, another 60-min EGG. The dominant frequency and peak power (amplitude) of the EGG, and the percentage of normal 2–4 cycles/min slow waves during each recording session were computed and compared between placebo and CCK. It was found that normal 3 cpm slow waves were recorded in all EGGs. Infusion of CCK had no effect on the frequency of the gastric slow wave and did not induce gastric dysrhythmias. It was also found that intravenous infusion of CCK significantly decreased the EGG peak power (amplitude) during the first hour after the meal (the infusion was given during this period) in comparison with placebo (P<0.05). This inhibitory effect on EGG peak power was sustained but not significant during the second postprandial hour (the infusion was not given during this period). It was concluded that intravenous infusion of CCK at a physiological concentration significantly decreased the postprandial EGG amplitude in normal humans, suggesting an inhibitory effect on postprandial gastric motility, but did not change the frequency and regularity of the gastric slow wave.     

Abnormal gastric myoelectrical activity and delayed gastric emptying in patients with symptoms suggestive of gastroparesis

Gastric myoelectrical activity modulates gastric motor activity. Abnormalities in gastric myoelectrical activity may be associated with gastric motility disorders. The aim of this study was to investigate the correlation of gastric myoelectrical activity with gastric emptying in symptomatic patients with and without gastroparesis. Ninety-seven patients with symptoms suggestive of gastroparesis participated in the study. Gastric myoelectrical activity was recorded using surface electrogastrography. The electrogastrogram (EGG) was recorded for 30 min in the fasting state and for 120 min after a solid test meal. Gastric emptying of the solid meal was simultaneously monitored for 120 min. Patients with delayed gastric emptying showed a significantly lower percentage of normal gastric slow waves (P<0.03) and a significantly reduced increase of the dominant power in the postprandial EGG (P<0.02). Postprandial EGG parameters were found to be able to predict delayed emptying of the stomach. Postprandial gastric dysrhythmia predicts delayed gastric emptying with an accuracy of 78%, while the abnormality in postprandial EGG power predicts delayed gastric emptying with an accuracy of 75%. All patients with abnormalities in both the rhythmicity and the power had delayed gastric emptying. Patients with delayed gastric emptying have a lower percentage of normal gastric slow waves in the EGG and a lower postprandial increase in the dominant power. Abnormalities in the postprandial EGG seem to be able to predict delayed emptying of the stomach. However, a normal EGG does not seem to guarantee normal emptying of the stomach.     

Gastric myoelectrical activity in diabetics with and without diabetic autonomic neuropathy

BACKGROUND/AIMS: The effects of diabetes mellitus on gastric myoelectrical activity has not been fully investigated. The aim of the present study was to investigate the pattern of gastric myoelectrical activity in noninsulin dependent diabetics, detected by electrogastrography in an attempt to clarify the relation between diabetic autonomic neuropathy and gastric myoelectrical abnormalities, if any. METHODOLOGY: The study was carried out on 34 noninsulin dependent diabetes (7 males, 27 females). Their age ranged from 35-60 years with mean age of 51.5 +/- 3.5 years. The EGG was recorded for 30 min in both the fasting and postprandial states, using an ambulatory EGG recording device (Digitrapper EGG, Synectics Medical). The adaptive spectral analysis method was used to assess the normality of the EGG. The EGG was defined as abnormal if: the percentage of normal slow waves (2.5-3.7 cycles/min) was below 70% during either the baseline or postprandial recording or there was a decrease in EGG peak power after the meal, or both. RESULTS: EGG abnormalities were detected in 13 patients (38.2%); 1 had tachygastria, 1 had bradygastria, 7 had dysrhythmias, and 4 had decreased EGG peak power after the meal. All diabetic patients with abnormal EGG suffer autonomic neuropathy. CONCLUSIONS: These results suggest that gastric myoelectrical abnormalities occur in a high proportion of noninsulin dependent diabetics and these abnormalities predominate in those patients with autonomic neuropathy.     

功能性消化不良患者胃肌电紊乱的发生率

背景：功能性消化不良（FD）的病理生理机制尚未完全阐明，消化道运动功能异常可能是主要发病机制之一。目的：通过胃电图检查探讨FD患者胃肌电紊乱的发生率，证实胃动力异常在FD发生中的作用。方法：368例FD患者行餐前和餐后体表胃电图榆查，对正常胃慢波百分比和胃电主功率两项参数进行分析。结果：根据正常胃慢波百分比，本组FD患者可分为胃电节律正常组（43．2％）、胃动过缓组（33．2％）、胃动过速组（6．2％）和混合性胃电节律紊乱组（17．4％）。在胃电节律正常的FD患者中，34．0％（54例）存在餐后／餐前胃电主功率比异常。结论：本组71．5％的FD患者存在胃肌电紊乱，证实胃动力异常在FD的发病机制中起有重要作用。     

Effects of Octreotide and Erythromycin on Gastric Myoelectrical and Motor Activities in Patients with Gastroparesis

Simultaneous recordings of gastric manometry andmyoelectrical activity were made in 10 patients withgastroparesis. Intravenous erythromycin (100 mg) wasadministered in the fasting state for a period of 30 min. Subcutaneous injection of octreotide(100 g) was administered before one of the fouridentical test meals. It was found that octreotidesignificantly decreased the antral motility index(30-min fasting: 4.51 ± 1.04 vs 1.75 ±0.97, P < 0.02; 60-min fed: 5.16 ± 1.44 vs 3.4± 1.41, P < 0.05) and the dominant power ofthe EGG (fasting power: 35.19 ± 1.54 vs 30.84± 1.57 dB, P < 0.004; postprandial powerincrease: 5.52 ± 1.06 vs 0.27 ± 0.87, P< 0.001). Erythromycin significantly increased theantral motility index (3.16 ± 0.96 vs 9.5± 0.61, P < 0.001) and the dominant power ofthe EGG (28.86 ± 1.57 dB vs 33.55 ± 1.59dB, P < 0.005) in the fasting state. An improvement in theregularity of the gastric slow wave was also noted witherythromycin. It was concluded that: (1) the inhibitoryeffect of octreotide on postprandial gastric motility and myoelectrical activity suggests thatcaution should be exercised when octreotide is used inpatients with gastroparesis; and (2) the stimulatoryeffect of erythromycin on gastric myoelectrical activity may enhance gastric motility and gastricemptying in patients with gastroparesis.     

Gastric involvement in systemic sclerosis: a prospective study

OBJECTIVES: This study aims to assess the prevalence of gastric electrical activity dysfunction with cutaneous electrogastrography (EGG), disturbances of gastric emptying function using radiopaque pellets, and gastric endoscopic abnormalities in patients with systemic sclerosis (SSc). We also investigate for an association between EGG and gastric-emptying data with clinical manifestations and esophageal motor disturbances. METHODS: Fasting and postprandial gastric electrical activity was studied in 22 consecutive patients with SSc (17 with and 5 without clinical gastric manifestations) and 22 age- and sex-matched healthy subjects. Gastric emptying of radiopaque pellets and gastroscopy were also performed in SSc patients. RESULTS: The prevalence of EGG disturbances was as high as 81.82% in SSc patients. SSc patients exhibited, compared with controls, higher median percentage of dominant frequency in bradygastria during the fasting period and lower median values for postprandial electrical power and postprandial to fasting ratio for electrical power. Gastric emptying of radiopaque pellets was delayed in 11 SSc patients, and gastroscopy demonstrated "watermelon stomach" in 3 SSc patients. No correlation was found between the severity of gastric impairment and clinical presentation, SSc duration and subsets, and esophageal manometric impairment. CONCLUSIONS: Our study underlines the high frequency of gastric dysfunction in SSc patients. It suggests the usefulness of EGG in SSc in noninvasively detecting disorders of gastric electrical activity at an early stage and symptomatic patients with gastroparesis (because there was a correlation between values of postprandial to fasting ratio for electrical power of < 1 on EGG and delayed gastric emptying). Gastric-emptying evaluation of radiopaque pellets may further be a helpful method to depict symptomatic SSc patients with gastroparesis. Finally, our series confirms that watermelon stomach diagnosis should be excluded in SSc patients presenting with gastrointestinal hemorrhage or with anemia related to iron deficiency.     

Effects of highly selective vagotomy on gastric myoelectrical activity

Changes in gastric myoelectrical activity following highly selective vagotomy were studied in 12 patients by means of electrogastrography (EGG) using cutaneous electrodes. Measurements were made before, 10 days after, and six months after operation. Eight patients undergoing cholecystectomy served as controls. Preoperatively all controls and patients had normal recordings. In the cholecystectomized patients no significant changes were found postoperatively. Ten days after highly selective vagotomy the normal initial postprandial dip in gastric ECA frequency and the subsequent increase in frequency and power were not seen. Tachygastrias were observed in three patients. Six months after operation the normal frequency and power responses to a test meal had returned, but both the fasting and postprandial ECA frequencies were raised significantly. It is concluded that highly selective vagotomy is associated with abnormalities in myoelectrical activity, in particular in the postprandial state, most of which are reversible with time.     

Enhanced postprandial gastric myoelectrical activity after moderate-intensity exercise

OBJECTIVE: The aim of this study was to investigate the change of postprandial gastric myoelectrical activity and its relation with vagal activity after exercise. METHODS: Nine subjects were studied in two sessions. In the control session, gastric myoelectrical activity was recorded using electrogastrography (EGG) for 30 min in the fasting state and 60 min after a test meal. In the exercise session, after the baseline recording of both the EGG and electrocardiogram (ECG), the subject was put on a cycle ergometer for exercise until reaching 50% of the maximum age-predicted heart rate for 10 min. The test meal was then given and the recording was resumed for 60 more minutes. Spectral analyses were performed on both the EGG and the heart rate variability derived from the ECG. RESULTS: The postprandial increment of the dominant power (p<0.05) and the percentage of the 2-4 cpm slow waves (p = 0.01) were significantly higher with exercise. The standard deviation of the postprandial dominant frequency was significantly decreased (more stable slow waves) with exercise (p<0.04). While cardiac vagal activity was significantly decreased after the meal, exercise did not significantly affect the postprandial change. CONCLUSIONS: Gastric slow waves become more regular, more stable, and of higher amplitude after exercise, and this enhancement is probably not mediated via the vagal pathway.     

Gastric Dysrhythmias and Delayed Gastric Emptying in Patients with Functional Dyspepsia

An association between dyspepsia, gastricmotility disorders, and myoelectrical abnormalities hasbeen noted. The objective of the present study was toinvestigate both antral myoelectrical activity and gastric emptying in patients with functionaldyspepsia (FD). Electrogastrography (EGG) was performedin 25 adult patients with FD, which had been evaluatedby score. After an overnight fast, for 1 hr in the pre- and postprandial state (370 kcalliquid-solid test meal) the following EGG parameterswere determined: dominant frequency [DF (cpm)], DF (%)in the normal range (2-4 cpm), bradygastria (<2 cpm), tachygastria (4-10 cpm), dominant frequencyinstability coefficient (DFIC), and postprandial tofasting power ratio (PR). The data were correlated toresults obtained in 20 age- and gender-matched controls. In addition, in 17 consecutive patients the EGGdata were compared to the gastric retention ofradionuclides after 60 min (liquid-solid phase labeledwith ^99mTc colloid). Patients with FDrevealed a preprandial increase in tachygastria compared to controls(P < 0.001). Of 17 FD, seven patients exhibiteddelayed gastric emptying (t60 retention >68%). Thesepatients showed significantly more pre- and postprandial tachygastrias than patients with normal gastricemptying (P < 0.05). The dyspeptic symptology and H.pylori status did not correlate with EGG andradioscintigraphy. Patients with FD frequently revealimpaired gastric emptying and increased tachygastria,which may have pathophysiological significance in someof these patients.     

An improved electrogastrographic system in measuring myoelectrical parameters

This study assessed the reliability of an improved electrogastrographic (EGG) system in recording stomach myoelectrical parameters and tried to establish the normal ranges of myoelectricity using this system. The analytical software of the current system mainly included an autoregressive modelling program to compute myoelectrical frequency and power. Forty healthy subjects were enrolled to receive myoelectrical measurement in two consecutively fasting and one postprandial 30 min sessions. The myoelectrical frequencies in both fasting and postprandial sessions were almost three cycles per min (c.p.m.) and showed little variation. The percentage of dominant frequencies (2.5–3.5 c.p.m.) in three sessions was approximately 80% while the computed myoelectrical powers in the first and second fasting sessions exhibited a significant correlation ( r = 0.84, P < 0.001). Meal ingestion increased the myoelectrical powers by 6.8 dB compared with the second fasting recording ( P < 0.001). The mean variation in myoelectrical amplitude for the ratio of second: first fasting session was 110.3 ± 88.8% (16–478%, median 88%). This new EGG system is, indeed, reliable for measuring myoelectrical frequency and power, whereas the interassay of recorded amplitudes appears markedly variable.     

Postprandial Response of Gastric Slow Waves: Correlation of Serosal Recordings with the Electrogastrogram

Controversial interpretations have been given to the postprandial increase in the dominant power (amplitude) of the electrogastrogram (EGG). The aim of this study was to find an appropriate interpretation of the postprandial EGG power changes. Simultaneous serosal and cutaneous recordings of gastric myoelectrical activity were made in 11 patients with gastroparesis in the fasting state and after the ingestion of 8 oz of water. The dominant frequency and corresponding power of the recording before and after water were computed using the power spectral analysis method. It was found that the dominant frequency of the EGG was the same as that of the serosal recording in 10 patients. One patient showed a substantial amount of dysrhythmia and no obvious dominant frequency was noted. A decrease in the dominant frequency was found in these 10 patients after the ingestion of water. Tachygastria of higher than 4 cycles/min was observed in one of 11 patients both in the prewater and postwater states. Consistent changes in amplitude after a drink of water were noted in both serosal recording and EGG. Statistical analysis demonstrated that the dominant power change after water computed from the EGG was correlated with that observed in the serosal recording (r = 0.757, P = 0.007). In conclusion, exogenous stimulation, such as ingestion of water, may change the amplitude of the gastric slow wave and this change is reflected in the EGG, suggesting that the change of the slow-wave amplitude is an important contributing factor to the postprandial change in the EGG dominant power.     

Role of sham feeding in postprandial changes of gastric myoelectrical activity

The aim of this study was to evaluate the role of sham feeding in postprandial changes of gastric myoelectrical activity. Eighteen asymptomatic healthy volunteers (10 men, 8 women; mean age: 31), with no history of gastrointestinal disease were studied. Gastric myoelectrical activity was recorded for 30 min at baseline, 30 min after sham feeding, and 1 hr after eating, using surface electrogastrography. The electrogastrogram (EGG) was analyzed by spectral analysis. It was found that the changes of postprandial EGG parameters were significantly correlated with those after sham feeding (EGG dominant power:r=0.6,P<0.01; dominant frequency:r=0.8,P<0.001; percentage of regular slow waves:r=0.7,P<0.003). We concluded that intrinsic gastric electrical activity can be altered by sham feeding and the cephalic phase of digestion plays an important role in the postprandial response of gastric myoelectrical activity.     

Impaired gastric myoelectricity in patients with chronic pancreatitis： Role of maldigestion

AIM: To investigate whether gastric myoelectrical activity was impaired in patients with chronic pancreatitis (CP) and to explore the role of pancreatic enzyme in regulating gastric myoelectrical activity. METHODS: Twenty CP patients and 20 controls participated in the study. Gastric myoelectrical activity was recorded by a homemade electrogastrography (EGG) device. Two experiments were carried out. In experiment one, EGG was recorded in both controls and CP patients. While in experiment two, either pancreatic enzymes or placebo was given together with test meals. Spectral analysis was used to generate various EGG parameters. RESULTS: The control subjects, but not the CP patients, showed typically increased postprandial dominant frequency. The postprandial dominant power (DP) increment (2.24±1.13 vs 5.35±0.96 dB, P= 0.04) and the percentage of normal 2-4 cpm slow waves (63.0±3.8% vs 77.4±3.1%, P<0.05) were lower in CP patients when compared with the control. In the 20 CP patients, the DP increment (4.76±1.02 vs 2.53±1.20 dB, P<0.05) and the postprandial percentage of normal 2-4 cpm (74.4±2.8% vs 64.8±5.7%, P<0.05) were significantly higher with pancreatic enzyme replacement than the placebo. CONCLUSION: CP patients have an abnormal postprandial stomach myoelectricity showing poor response in dominant frequency/power and regularity, whereas these abnormalities are corrected after pancreatic enzyme replacement. Maldigestion is likely to be the factor leading to abnormal postprandial gastric myoelectricity of CP patients.     

Cutaneous gastric electrical stimulation alters gastric motility in dogs: New option for gastric electrical stimulation?

Background and Aim:  We investigated the effects of cutaneous gastric electrical stimulation (CGES) on gastric myoelectrical activity, postprandial antral contractions and gastric tone in dogs.
Methods:  CGES was carried out via abdominal surface electrodes over the stomach. After an overnight fast, gastric slow waves were recorded from the serosal electrodes in six dogs at a frequency of 4.4 cycles/min (c.p.m.) or 10 c.p.m. Nine dogs were used for the measurement of postprandial antral contractions. Gastric tone at baseline and during CGES was measured in six of the dogs.
Results:  We found that: (i) CGES at 4.4 c.p.m. decreased slow wave frequency (5.1 vs 4.6 c.p.m., P  < 0.05) and increased slow wave power (−6.2 vs 2.7 c.p.m., P  < 0.05); CGES at 10 c.p.m. increased slow wave frequency (5.1 vs 9.2 dB, P  < 0.05) and decreased normal slow waves (85.4% vs 60.0%, P  < 0.05); (ii) CGES at 10 c.p.m. significantly suppressed postprandial antral contractions ( P  < 0.01); (iii) CGES had no effects on gastric tone.
Conclusions:  CGES is capable of altering gastric slow waves and inhibiting gastric motility. It may have therapeutic potential for treating eating disorders, such as obesity. However, clinical studies are needed to explore the potential of CGES.     

Mediation of transcatheter arterial chemoembolization induced gastric slow-wave dysrhythmia by endogenous prostaglandin

BACKGROUND AND AIMS: In recent years, gastric slow-wave dysrhythmias induced by transcatheter arterial chemoembolization (TACE) have been observed. Enhanced endogenous prostaglandin may be a possible mechanism for the myoelectrical changes. The aim of this study was to evaluate whether the gastric slow-wave dysrhythmias induced by TACE may be mediated by ketoprofen, a prostaglandin synthesis inhibitor. METHODS: Twenty-three patients with hepatocellular carcinoma (HCC) admitted for TACE were enrolled. A follow-up TACE was scheduled to take place 2 months later. During the next admission for TACE, 50 mg of ketoprofen was given intramuscularly 12 h for 3 days, beginning 48 h before TACE, as premedication. Cutaneous electrogastrography (EGG) was performed before and within 24 h after TACE. RESULTS: The results showed that the change in the fasting EGG parameters after TACE without premedication was not statistically significant. However, the postprandial EGG parameters, including the dominant frequency (DF); the percentages of DF in the normal, bradygastric and tachygastric range; along with the dominant frequency instability coefficient, deteriorated significantly after the procedure (P < 0.01). After the follow-up TACE with ketoprofen premedication, neither the fasting nor postprandial EGG parameters in the control group changed significantly. CONCLUSIONS: Gastric slow-wave dysrhythmias induced by TACE may be mediated by ketoprofen, a prostaglandin synthesis inhibitor, in HCC patients. However, the improvement in the gastric myoelectrical activity does not eliminate the degree of nausea/vomiting after TACE.     

Multichannel electrogastrography (EGG) in symptomatic patients: a single center study

OBJECTIVES: To determine the value of multichannel versus conventional single-channel electrogastrography (EGG) and of an additional postprandial hour recording in symptomatic patients. METHODS: Eighteen normal subjects and 47 patients with upper GI symptoms underwent multichannel EGG with four cutaneous recording electrodes placed on the antral axis. Fasting EGG was recorded for 1 h, followed by meal ingestion, followed by two 1-h postprandial EGG recordings. Variables assessed: (1) dominant frequency (DF) and its power; (2) percent time in normal (2-4) cpm frequency; (3) average percent of slow wave coupling (% SWC). RESULTS: Normal values for single-channel EGG were: (1) DF from 2.5-3.3, 2.7-3.5, and 2.6-3.5 cpm in the fasting, first, and second postprandial hours; (2) percentage of time in 2-4 cpm: >50%, >65%, and >65% in the fasting, first, and second postprandial hours. Normal values for percent SWC using multichannel EGG were >50%, >55%, >55% in the fasting, first, and second postprandial hours. In the symptomatic patients, an abnormal 2-h single-channel EGG was obtained in 16 of 47 (34%) patients. Adding an additional 1 h of postprandial recording identified another 4 abnormal patients (20/47 = 43%). With multichannel EGG, abnormal results were obtained in 24 of 47 patients (51%) with the 2-h study. An additional 1 h of postprandial recording identified another 4 patients as abnormal (28/47 = 60%). CONCLUSIONS: Multichannel EGG recording improved the detection of abnormal gastric myoelectric activity in symptomatic patients. This study also demonstrates prolonging the postprandial recording to 2 h increases the diagnostic yield for both single-channel and multichannel EGG.     

Effect of gastric acid suppressants on human gastric motility

Background—The effect of histamine H₂receptor antagonists on gastric emptying is controversial.
Aims—To determine the effects of ranitidine,famotidine, and omeprazole on gastric motility and emptying.
Patients and methods—Fifteen normal subjectsunderwent simultaneous antroduodenal manometry, electrogastrography(EGG), and gastric emptying with dynamic antral scintigraphy (DAS).After 30 minutes of fasting manometry and EGG recording, subjectsreceived either intravenous saline, ranitidine, or famotidine, followed by another 30 minutes recording and then three hours of postprandial recording after ingestion of a radiolabelled meal. Images were obtainedevery 10-15 minutes for three hours to measure gastric emptying andassess antral contractility. Similar testing was performed afteromeprazole 20 mg daily for one week.
Results—Fasting antral phase III migrating motorcomplexes (MMCs) were more common after ranitidine (9/15 subjects,60%), famotidine (12/15, 80%), and omeprazole (8/12, 67%) comparedwith placebo (4/14, 29%; p<0.05). Postprandially, ranitidine,famotidine, and omeprazole slowed gastric emptying, increased theamplitude of DAS contractions, increased the EGG power, and increasedthe antral manometric motility index.
Conclusions—Suppression of gastric acid secretionwith therapeutic doses of gastric acid suppressants is associated withdelayed gastric emptying but increased antral motility.

Keywords:gastric motility; gastric emptying; histamineH₂ receptor antagonists; proton pump inhibitors; gastricacid secretion; scintigraphy

     

Effect of sildenafil on gastric emptying and postprandial frequency of antral contractions in healthy humans

BACKGROUND: Sildenafil is known to block phosphodiesterase type 5, which degrades nitric oxide-stimulated cyclic guanosine monophosphate, thereby relaxing smooth muscle cells in various organs. The effect of sildenafil on gastric motor function after a meal was investigated in healthy humans. METHODS: Ten healthy male volunteers (21-28 years) participated in a placebo-controlled, double-blind, cross-over study. In random order and on two separate days each volunteer ingested either 50 mg sildenafil (Viagra, Pfizer, New York, N.Y., USA) or placebo. A gamma camera technique was used to measure gastric emptying and postprandial frequency of antral contractions. RESULTS: The area under the curve of gastric retention versus time of liquid or solid radiolabelled marker was not changed by sildenafil intake, nor was the postprandial frequency of antral contractions affected by sildenafil. CONCLUSION: A single dose of 50 mg sildenafil does not change gastric emptying or postprandial frequency of antral contractions in healthy volunteers.