The factors influencing appetite in humans are poorly understood. There is a weak relation between appetite and gastric emptying in normal subjects. Recent studies have shown that fasting and postprandial antral areas increase in patients with functional dyspepsia compared with normal subjects. We evaluated the hypothesis that antral area, and hence antral distention, is a significant determinant of postprandial fullness. Fourteen normal subjects had simultaneous measurements of gastric emptying by scintigraphy and antral area by ultrasound after ingestion of 350 mL 20% glucose. Fullness and hunger were assessed by visual analog scales. Measurements of the gastric-emptying half time (t1/2) by scintigraphy and ultrasound were not significantly different (129.6 +/- 11.8 min compared with 115.6 +/- 11.4 min). Fullness increased (P < 0.001) and hunger decreased (P < 0.001) after the drink. Both fullness and the magnitude of the increase in fullness after the drink were related to antral area (r > 0.56, P < 0.05), the increase in antral area (r > 0.59, P < 0.05), and the scintigraphic content of the distal stomach (r > 0.57, P < 0.05), but not to the ultrasound or scintigraphic t1/2 values. In contrast, hunger and the magnitude of the decrease in hunger after the drink were not related to either antral area, the increase in antral area, or the rate of gastric emptying. We conclude that postprandial fullness, but not hunger, was closely related to antral distention in normal subjects.

The effects of the nitric oxide donor nitroglycerin on gastric emptying and antropyloroduodenal motility were evaluated in nine healthy male subjects (ages 19–36 yr). Antropyloroduodenal pressures were recorded with a manometric assembly that had nine side holes spanning the antrum and proximal duodenum and a pyloric sleeve sensor; gastric emptying was quantified scintigraphically. In each subject, the emptying of 300 ml of 25% glucose labeled with99mTc was assessed on two separate days during intravenous infusion of either nitroglycerin (5 μg/min in 5% dextrose) or 5% dextrose (control). Studies were performed with the subject in the supine position; blood pressure and heart rate were monitored. Nitroglycerin had no significant effect on blood pressure or heart rate. Nitroglycerin slowed gastric emptying ( P < 0.02), and this was associated with greater retention of the drink in the proximal stomach ( P < 0.05). In both nitroglycerin and control studies, ingestion of the drink was associated with an increase in the number of isolated pyloric pressure waves ( P < 0.05) and antral pressure wave sequences ( P < 0.05). Nitroglycerin reduced the number of isolated pyloric pressure waves ( P < 0.05), basal pyloric pressure ( P < 0.05), and the number of antral pressure wave sequences ( P < 0.05), but not the total number of antral pressure waves. The rate of gastric emptying and the number of isolated pyloric pressure waves were inversely related during control ( P = 0.03) and nitroglycerin ( P < 0.05) infusions. We conclude that in normal subjects, 1) gastric emptying of 300 ml of 25% glucose is inversely related to the frequency of phasic pyloric pressure waves, and 2) nitroglycerin in a dose of 5 μg/min inhibits pyloric motility, alters the organization but not the number of antral pressure waves, and slows gastric emptying and intragastric distribution of 25% glucose.

The cutaneous electrogastrogram (EGG) and intraluminal antropyloroduodenal pressures were recorded in 12 healthy volunteers for 30-min periods during phase II of the interdigestive motor complex, during intraduodenal infusion of 10% triglyceride, and after intravenous erythromycin (3 mg/kg). During phase II, the frequency of the EGG was relatively constant in each individual, with a median frequency of 0.046 Hz [2.8 counts per minute (cpm)]. EGG frequency was greater (P < 0.05) than the median rate of antral pressure waves (1.8 cpm). The suppression of antral pressure waves (P < 0.05) and stimulation of isolated pyloric pressure waves (IPPWs) (P < 0.05) produced by triglyceride infusion were not associated with changes in EGG frequency compared with phase II. The frequency of the EGG and the rate of IPPWs were comparable. After erythromycin, EGG frequency was 0.03 Hz (1.8 cpm), less than during both phase II and triglyceride infusion (P < 0.05) and almost identical to the rate of antral pressure waves. Pressure waves were nearly always associated with an EGG signal. In contrast, the temporal relationship between the EGG signal and pressure waves was variable. During triglyceride infusion (r = 0.83, P < 0.001) and after erythromycin (r = 0.83, P < 0.001) there was a close (approximately 1:1) relationship between the rate of pressure waves and EGG frequency. However, there was no significant relationship (r = 0.32, not significant) between the number of pressure waves and EGG frequency frequency during pase II.(ABSTRACT TRUNCATED AT 250 WORDS)

We conclude that intraduodenal tryptophan has stereospecific effects on pyloric and duodenal motility. Although the precise contribution of these differential effects to gastric emptying remains to be clarified, they may be partially responsible for the differences in gastric emptying of D-tryptophan and L-tryptophan.

The retardation of gastric emptying induced by infusion of triglyceride into the small intestine is associated with suppression of antral pressure waves and stimulation of basal pyloric tone in combination with phasic pressure waves localized to the pylorus. The role of nitric oxide (NO) mechanisms in the control of pyloric motility was evaluated in 12 healthy male subjects (21-43 years), using the NO donor glyceryl trinitrate (GTN). Antropyloric pressures were measured with a manometric assembly incorporating nine sideholes, spanning the antrum and proximal duodenum, and a pyloric sleeve sensor. On separate days, an intraduodenal triglyceride infusion (10% intralipid at 1 mL min-1) was started during antral phase I activity and continued for 60 min. On one of the days GTN (600 micrograms) was given sublingually 20 min after start of the triglyceride infusion. The tonic pyloric motor response to triglyceride [5.6 (SEM 0.8,) vs. 2.7 (1.3) mmHg, P < 0.001] and both the number 3.2 (0.2) vs. 2.2 (0.2) min-1, P < 0.05] and amplitude [40 (4) vs. 27 (5) mmHg, P < 0.05] of phasic isolated pyloric pressure waves were reduced by GTN. These observations suggest that NO mechanisms are involved in the regulation of pyloric motor activity in humans.

To evaluate the effects of cisapride on gastric emptying of extracellular fat and hunger and fullness 10 volunteers consumed a meal consisting of 60 ml technectium-99m (99mTc)-V-thiocyanate labelled olive oil and 290 ml indium113m (l13mIn) labelled soup after taking cisapride (10 mg four times daily orally) and placebo, each for four days, in randomised, double blind fashion. Gastric emptying was quantified scintigraphically. Hunger and fullness before and after the meal were evaluated using visual analogue scales. Cisapride accelerated gastric emptying of oil and aqueous components by reducing the lag phase mean (SEM) (20.3 (7.0) min v 40.7 (4.1) min (p<0.05) for oil and 4.1 (2.5) min v 10.0 (3.1) min (p<0.05) for aqueous). Cisapride had no effect on the post-lag emptying rate of oil. Treatment with cisapride was associated with reduced retention of oil in the proximal stomach (p<0.05). Subjects were more hungry before ingestion of the meal while receiving cisapride (6.7 (0.9) v 3.9 (0.7), p<0.001). The scores for hunger at 120 and 180 minutes were inversely related to gastric emptying of oil on both cisapride p<0.0Ol Disordered gastric emptying, particularly delayed emptying, occurs frequently and may be associated with gastrointestinal symptoms such as nausea, abdominal pain, and vomiting.' In normal subjects gastric23 and small intestinal4 administration of fat retard gastric emptying. In patients who suffer from unexplained upper abdominal symptoms, gastric emptying may be exacerbated by intake of high fat meals and in patients with non-ulcer dyspepsia, delay in gastric emptying is more commonly seen with nutrient rich (high fat) than with bland meals.5 The intragastric distribution of fatty meals is also frequently abnormal in patients with non-ulcer dyspepsia.6The most effective therapeutic approach to the treatment of symptomatic gastroparesis is the use of drugs designed to increase the rate of gastric emptying' and cisapride is arguably the gastrokinetic drug of first choice.7 Cisapride has been shown to abolish the slowing of gastric emptying induced by giving fat immediately before a meal in normal subjects,23 but the effects of cisapride or other prokinetic agents on gastric emptying of fat have not been evaluated to our knowledge. Recent studies performed by ourselves and others show that gastric emptying of extracellular fat is influenced by both its intragastric distribution, and feedback from receptors in the small intestine. Efjects of cisapride on gastric emptying of oil and aqueous meal components, hunger, andfullnessWe have now used a specific radioisotopic marker of extracellular fat to evaluate theWeffects of cisapride on gastric emptying and intragastric distribution of oil and aqueous meal components and appetite in normal subjects. Methods SubjectsTen healthy volunteers (one male, nine female), mean age 22 years (range 18-28) and mean body weight 67.2 kg (range 39.6-98 4) had two measurements of gastric emptying, hunger and fullness, once after taking cisapride and the other ...

Abstract.The relationship between calcium absorption and gastric emptying and the precision of measurement of fractional calcium absorption using a single isotope technique were evaluated in 14 normal postmenopausal women (age range 61 -72 years). On two occasions separated by between 5 and 15 days, each subject was given 250mL water containing 0.2MBq of 45Ca in 20mg of calcium carrier as the chloride, 20 mg kg-I paracetamol and 9 MBq of 9 9 m T~ sulphur colloid. Venous blood samples were taken at -2, 15, 30, 45, 60, 90, 120, 150 and 180min after consumption of the drink, and gastric emptying (GE) was monitored with a gamma camera. Fractional calcium absorption in the first hour (a6) was calculated from the blood samples obtained at 15, 30, 45, 60, 90 and 120min. An absorption rate was also derived from the 60 min sample using only a calibration curve ( a l ) .There were close correlations between radiocalcium absorption on the two study days (r = 0.89, P < 0.001 for both a I and ' Y 6 ) and between al and a 6 (r = 0.93, P < 0,001). Plasma paracetamol concentrations at 15 min were directly related to the early phase of GE ( r = 0.42, P c 0.05). In contrast, calcium absorption was inversely related to GE (r = 0.45, P < 0.05). We conclude that radiocalcium absorption is not greatly influenced by gastric emptying rate and that the single blood sample procedure has similar precision to the six-blood sample test.

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