Influence of blood glucose levels on rat liquid gastric emptying

Decreased L-type calcium current in antral smooth muscle cells of STZ-induced diabetic rats

BACKGROUND

Diabetic gastroparesis (delayed gastric emptying) is associated with antral hypomotility. L-type Ca(2+) channels play an important role in generation of action potentials and activation of contractions. This study was designed to investigate if the function of the L-type Ca(2+) channels of antral circular smooth muscle cells (SMCs) is impaired in streptozotocin (STZ)-induced diabetic rats.

METHODS

Eight weeks after the injection of STZ or vehicle, whole-cell patch clamp was used to record Ca(2+) currents, and isometric tension recording was used to measure Ca(2+) influx-induced contractions in circular muscle strips. Solid gastric emptying was measured in diabetic and control rats. Protein expression of Ca(2+) αlC-subunit in antral smooth muscles was compared between diabetic and control rats.

KEY RESULTS

(1) Solid gastric emptying, independent of age or bodyweight, was slower in the diabetic rats, even after acute correction of hyperglycemia. (2) Verapamil, a potent calcium channel blocker, dose dependently reduced solid gastric emptying in normal rats. (3) Current density of L-type Ca(2+) channel at 10 mV in antral circular SMCs was significantly decreased in the diabetic rats (-9.8 ± 0.7 pA/pF vs -15.9 ± 1.0 pA/pF in control, p < 0.001). However, protein expression of the Ca(2+) channel in antral muscles did not differ between diabetic and control rats. (4) Contractile responses to 1 and 3 mM [Ca(2+) ] were significantly reduced in the diabetic antral circular muscle strips, indicative of reduced Ca(2+) influx.

CONCLUSIONS & INFERENCES

These data suggested that the decreased L-type Ca(2+) current in antral SMCs may contribute to antral hypomotility in STZ-induced diabetic rats.

Validation of octanoate breath test for measuring gastric emptying in rats

Background/Aims

Lack of simple and repeatable tests hampers gastric emptying studies in rats. The aim of this study was to adapt the ¹⁴C-octanoate solid gastric emptying breath test for application in rats, and to validate it against radioscintigraphic method.

Methods

After ingestion of a meal containing 3 mCi ^99mTc and 2 µCi ¹⁴C-octanoate, 23 male Wistar rats were placed on a gamma camera in a airflow container. Scintigraphic images were taken at regular intervals. The amount of ¹⁴CO₂ in a regularly replaced hyamine hydroxide solution, capturing CO₂ in the outflow air, was counted using liquid scintillation spectrometry. ^99mTc gastric retention curves and ¹⁴CO₂-excretion curves were fitted to their respective data. Three rats underwent the same procedures after administration of atropine.

Results

Overall T_r10% (time at which 10% of the original amount of ^99mTc remained in the stomach) was 355 ± 64 minutes; T_e90% (time at which 90% of total amount of ¹⁴CO₂ was excreted) was 325 ± 106 minutes. Their correlation coefficient was 0.71, R-square 0.50 and P < 0.005. T_r1/2 (50% of original amount of ^99mTc remained) was 124 ± 28 minutes; T_e1/2 (50% of total amount of ¹⁴CO₂ excreted) 114 ± 32 minutes. Their correlation coefficient was 0.83 with R-square of 0.69 and P < 0.00005. In 12 immobilized animals correlation was even better: correlation coefficient 0.84; R-square 0.71 and P < 0.001 (T_r10% was 388 ± 117 minutes; T_e90% 532 ± 219 minutes; T_r1/2 of 165 ± 54 minutes; T_e1/2 of 175 ± 67 minutes). Atropine significantly lengthened all emptying times: 904 ± 307 and 1461 ± 684 minutes for T_r10% and T_e90%, respectively; and 432 ± 117 minutes for T_r1/2 and 473 ± 190 minutes for T_e1/2.

Conclusions

We adapted and validated the ¹⁴C-octanoate gastric emptying breath test for application in rats.

Gastrointestinal motility changes and myenteric plexus alterations in spontaneously diabetic biobreeding rats

BACKGROUND/AIMS

Type 1 diabetes is often accompanied by gastrointestinal motility disturbances. Vagal neuropathy, hyperglycemia, and alterations in the myenteric plexus have been proposed as underlying mechanism. We therefore studied the relationship between vagal function, gastrointestinal motiliy and characteristics of the enteric nervous system in the biobreeding (BB) rat known as model for spontaneous type 1 diabetes.

METHODS

Gastric emptying breath test, small intestinal electromyography, relative risk-interval variability, histology and immunohistochemistry on antral and jejunal segments were performed at 1, 8 and 16 weeks after diabetes onset and on age-matched controls.

RESULTS

We observed no consistent changes in relative risk-interval variability and gastric emptying rate. There was however, a loss of phases 3 with longer duration of diabetes on small intestinal electromyography. We found a progressive decrease of nitrergic neurons in the myenteric plexus of antrum and jejunum, while numbers of cholinergic nerve were not altered. In addition, a transient inflammatory infiltrate in jejunal wall was found in spontaneous diabetic BB rats at 8 weeks of diabetes.

CONCLUSIONS

In diabetic BB rats, altered small intestinal motor control associated with a loss of myenteric nitric oxide synthase expression occurs, which does not depend on hyperglycemia or vagal dysfunction, and which is preceded by transient intestinal inflammation.

Mechanisms of burn-induced impairment in gastric slow waves and emptying in rats

Delayed gastric emptying is common following severe large cutaneous burns; however, the mechanisms of burn-induced delayed gastric emptying remain unknown. The aim of this study was to explore the possible involvement of hyperglycemia and cyclooxygenase-2 receptors in the burn-induced gastric dysrhythmias. Gastric slow waves and gastric emptying were assessed in rats 6 h following sham or burn injury. Animals were randomized to one sham-burn and seven burn groups: untreated; two groups of saline treated (control); insulin treated (5 IU/kg); cyclooxygenase-2 inhibitor treated (10 mg/kg); ghrelin treated (2 nmol/rat); and gastric electrical stimulation treated. It was found that 1) severe burn injury impaired gastric slow waves postprandially and delayed gastric emptying; 2) the impairment in gastric slow waves included a decrease in the slow-wave frequency and in the percentage of normal slow waves, and an increase in the percentage of bradygastria (P = 0.001, 0.01, and 0.01, respectively vs. preburn values). None of the gastric slow-wave parameters was significantly correlated with gastric emptying; 3) cyclooxygenase-2 inhibitor normalized burn-induced delayed gastric emptying (P = 0.3 vs. sham-burn), but not gastric dysrhythmias (P < 0.002 vs. sham), whereas insulin normalized both gastric emptying (P = 0.4 vs. sham-burn) and gastric dysrhythmias (P = 0.3 vs. sham-burn); 4) both gastric electrical stimulation and ghrelin accelerated burn-induced delayed gastric emptying (P = 0.002 and 0.04, respectively, vs. untreated burn). In conclusion, hyperglycemia alters gastric slow-wave activity and delayed gastric emptying, while cyclooxygenase-2 inhibition delays gastric emptying without altering gastric slow-wave activity.

Gastric emptying of enterally administered liquid meal in conscious rats and during sustained anaesthesia

BACKGROUND

Gastric motility studies are frequently conducted with anaesthetized animal models. Some studies on the same animal species have reported differences in vagal control of the stomach that could not be explained solely by slightly different experimental conditions. A possible limitation in the comparison between similar studies relates to the use of different anaesthetic agents. Furthermore, anaesthetic effects may also limit generalizations between mechanistic studies of gastric function and the gastric function of conscious animals. In the present study, we used the [(13)C]-breath test following a liquid mixed-nutrient test meal (Ensure), 1 ml) with the aim to investigate the rate of gastric emptying in animals that were either conscious or anaesthetized with either Inactin or urethane.

METHODS

One week after determining the maximum (13)CO(2) concentration, time to peak [(13)C] recovery and gastric half emptying time in control, conscious rats, we repeated the experiment in the same rats anaesthetized with Inactin or urethane.

KEY RESULTS

Our data show that Inactin anaesthesia prolonged the time to peak [(13)C] recovery but did not significantly reduce the maximum (13)CO(2) concentration nor delay gastric half emptying time. Conversely, urethane anaesthesia resulted in a significant slowing of all parameters of gastric emptying as measured by the maximum (13)CO(2) concentration, time to peak [(13)C] recovery and half emptying time.

CONCLUSIONS & INFERENCES

Our data indicate that Inactin(R) anaesthesia does not significantly affect gastric emptying while urethane anaesthesia profoundly impairs gastric emptying. We suggest that Inactin(R), not urethane, is the more suitable anaesthetic for gastrointestinal research.

Effects of mitemcinal (GM-611), an orally active erythromycin-derived prokinetic agent, on delayed gastric emptying and postprandial glucose in a new minipig model of diabetes

AIMS

This study was conducted to evaluate the suitability of a new minipig model for investigating aspects of diabetes such as delayed gastric emptying and glucose metabolism abnormalities, and to test the effects of mitemcinal (GM-611), an orally active erythromycin-derived motilin receptor agonist, on gastric emptying and postprandial glucose in normal and diabetic minipigs.

METHODS AND RESULTS

Intravenous injection of 300 mg/kg streptozotocin (STZ) to 5-week-old minipigs induced moderate hyperglycemia (about 200 mg/dl) for >80 weeks without insulin treatment. Decreased insulin production (P<.05), increased area under the glucose curve (P<.05), and slower glucose disappearance (P<.05) were demonstrated, and there was no severe inhibition of body weight gain, liver failure, or renal failure. Gastric emptying was significantly delayed in diabetic minipigs (P<.05) at 80 weeks, but not at 40 weeks, post-STZ. Oral administration of mitemcinal (5 mg/kg) at 80 weeks accelerated gastric emptying and induced a similar postprandial glucose profile in normal and diabetic minipigs with delayed gastric emptying.

CONCLUSIONS

The new diabetic minipig model showed suitability for investigating diabetes, gastric emptying, and plasma glucose excursions. Since delayed gastric emptying and irregular plasma glucose excursions are characteristic of diabetic gastroparesis, the accelerating and regulating effects of mitemcinal on this model add to the existing evidence that mitemcinal is likely to be useful for treating diabetic gastroparesis.

Depletion of peptidergic innervation in the gastric mucosa of streptozotocin-induced diabetic rats

Autonomic neuropathy affecting the gastrointestinal system is a major presentation of diabetic neuropathy. Changes in the innervation of gastric mucosa or muscle layers can contribute to gastrointestinal symptoms. The present study investigated this issue by quantitatively analyzing the immunohistochemical patterns of the gastric innervation in rats with streptozotocin (STZ)-induced diabetes. In control rats, calcitonin gene-related peptide (CGRP) and substance P (SP) (+) nerve fibers appeared in the gastric mucosa and muscle layers. Double immunohistochemical staining showed that immunoreactivities for SP and CGRP were co-localized with a pan-neuronal marker protein gene product 9.5. Both SP (+) nerve fibers (p<0.001) and CGRP (+) nerve fibers (p<0.005) were decreased in the gastric mucosa within 4 weeks of diabetes; the reduction persisted throughout 24 weeks. Diabetic rats treated with insulin did not show decrease of SP or CGRP (+) fibers in the mucosa 4 weeks after STZ injection (p>0.05). There was no significant change in SP (+) nerve fibers (p>0.05) or CGRP (+) nerve fibers (p>0.05) of the gastric muscle layers. Reverse transcription-polymerase chain reaction (RT-PCR) showed that the expression levels of SP and CGRP mRNA in the thoracic dorsal root ganglia were similar between diabetic and control animals (p>0.05). Qualitative and quantitative ultrastructural examinations on the gastric mucosa documented unmyelinated nerve degeneration. These results suggest the existence of gastric sensory neuropathy in STZ-induced diabetes, and this pathology provides a foundation for understanding diabetic gastropathy.

Interaction of carbohydrate metabolism and rat liquid gastric emptying in sustained running

BACKGROUND

Moderate to severe running usually leads to gastrointestinal dysmotility and critical energy exhaustion. It is unknown whether the carbohydrate metabolism of runners can influence gastric emptying (GE). Using a running rat model, the present study explored the impact of exercise/carbohydrate metabolism on liquid GE.

METHODS

Rats were put on the runways of a moving treadmill for 1 h. Trained rats underwent daily running 5 days a week for 4 weeks. Untrained rats were those put on a quiet treadmill to serve as sham exercise. On the motility study day, trained and untrained rats ran for 45 min. After orogastric feeding of radiochromium marker, they resumed running for an additional 15 min and were then killed in order to measure GE. Another group of trained and untrained rats received lactate infusion for 1 h in the quiet condition to measure their GE. The third group of rats received glucose infusion during running to measure GE.

RESULTS

Running of untrained (P < 0.05) and trained (P < 0.01) rats enhanced GE compared to sham exercise. Running for the untrained rats rather than the trained counterparts had diminished plasma glucose level (P < 0.05). Running also elevated plasma lactate levels for both untrained (P < 0.001) and trained rats (P < 0.01). Lactate infusion delayed GE in untrained (P < 0.01) and trained rats (P < 0.05). Glucose infusion of untrained rats during running was not only to correct hypoglycemia (P < 0.01) but also to restore their enhanced GE (P < 0.01).

CONCLUSIONS

Running-induced hypoglycemia, rather than lactate accumulation, is one of the essential factors leading to enhanced liquid GE in untrained rats.

Neuropathology and pathogenesis of diabetic autonomic neuropathy

Autonomic neuropathy is a significant complication of diabetes resulting in increased patient morbidity and mortality. A number of studies, which have shown correspondence between neuropathologic findings in experimental animals and human subjects, have demonstrated that axonal and dendritic pathology in sympathetic ganglia in the absence of significant neuron loss represents a neuropathologic hallmark of diabetic autonomic neuropathy. A recurring theme in sympathetic ganglia, as well as in the pot-ganglionic autonomic innervation of various end organs, is the involvement of distal portions of axons and nerve terminals by degenerative or dystrophic changes. In both animals and humans, there is a surprising selectivity of the diabetic process for subpopulations of autonomic ganglia, nerve terminals within sympathetic ganglia and end organs, from end organ to end organ, and between vascular and other targets within individual end organs. Although the involvement or autonomic axons in somatic nerves may reflect an ischemic pathogenesis, the selectivity of the diabetic process confounds simple global explanations of diabetic autonomic neuropathy as the result of diminished blood flow with resultant tissue hypoxia. A single unifying pathogenetic hypothesis has not yet emerged from clinical and experimental animal studies, and it is likely that diabetic autonomic neuropathy will be shown to have multiple causative mechanisms, which will interact to result in the variety of presentations of autonomic injury in diabetes. Some of these mechanisms will be shared with aging changes in the autonomic nervous system. The role of various neurotrophic substances and the polyol pathway in the pathogenesis and treatment of diabetic neuropathy likely represents a two-edged sword with both salutary and exacerbating effects. The basic neurobiologic process underlying the diabetes-induced development of neuroaxonal dystrophy, synaptic dysplasia, defective axonal regeneration, and alterations in neurotrophic substance may be mechanistically related.

Hyperglycemia impairs antro-pyloric coordination and delays gastric emptying in conscious rats

Delayed gastric emptying has been shown in diabetes. Although it has been proposed that hyperglycemia, and not only autonomic neuropathy, contributes to the pathogenesis of delayed gastric emptying, the inhibitory mechanism of hyperglycemia on gastric emptying remains unclear. We studied the effects of hyperglycemia per se on gastric emptying and postprandial gastric motility in conscious rats. Liquid and solid gastric emptying were compared between saline-infused rats and D-glucose-infused rats. Two strain gauge transducers were implanted on the antrum and pylorus and the postprandial antro-pyloric coordination was compared between euglycemia and hyperglycemia. D-glucose infusion for 30 min increased blood glucose level from 5.4 +/- 0.5 to 13.0 +/- 1.3 mM and significantly delayed gastric emptying. Forty minutes after the feeding, contractions with low frequency (<3 cycles min(-1)) and high amplitude (>15 g) of the antrum were observed. This period reflects the emptying process of the gastric content and the coordination between the antrum and pylorus was frequently observed. D-glucose infusion significantly reduced feeding-induced antral contractions and abolished the number of episodes of antro-pyloric coordination. Sham feeding-induced gastric contractions were also significantly reduced by hyperglycemia. Postprandial antro-pyloric coordination was not observed in vagotomized rats, suggesting a mediation of vagus nerve. It is concluded that hyperglycemia impairs antral contractions and antro-pyloric coordination in rats. The inhibitory effect of hyperglycemia on gastric emptying is mediated, at least in part, via impaired vagal activity.

Gastric distension-induced pyloric relaxation: central nervous system regulation and effects of acute hyperglycaemia in the rat

1. The pylorus plays an important role in the regulation of gastric emptying. In addition to the autonomic neuropathy associated with long-standing diabetes, acute hyperglycaemia per se has effects on gastric emptying. In this study, the role of the central nervous system in modulating the effects of hyperglycaemia on gastric distension-induced pyloric relaxation was investigated. 2. Gastric distension-induced pyloric relaxation was significantly reduced by subdiaphragmatic vagotomy, hexamethonium (20 mg kg(-1)) and N (G)-nitro-L-arginine methyl ester (L-NAME; 10 mg kg(-1)), a nitric oxide synthase (NOS) biosynthesis inhibitor, in anaesthetized rats. In contrast, neither splanchnectomy nor guanethidine (5 mg kg(-1)) had an effect. 3. An intravenous (I.V.) infusion of D-glucose (20 %) for 30 min, which increased blood glucose concentrations from 5.4 to 12.8 mM, significantly inhibited gastric distension-induced pyloric relaxation. 4. An intracerebroventricular (I.C.V.) injection of D-glucose (3 micromol) also significantly inhibited gastric distension-induced pyloric relaxation without affecting peripheral blood glucose concentrations. 5. I.V. infusion of D-glucose significantly elevated hypothalamic neuropeptide Y (NPY) concentrations. 6. Intracerebroventricular (I.C.V.) administration of NPY (0.03--3 nmol) and a Y1 receptor agonist, [leu(31), pro(34)] NPY (0.03--3 nmol), significantly inhibited gastric distension-induced pyloric relaxation in a dose-dependent manner. 7. I.C.V. administration of a Y1 receptor antagonist, BIBP 3226 (30 nmol), and of a NPY antibody (titre 1:24 000, 3 microl) abolished the inhibitory effects of hyperglycaemia on gastric distension-induced pyloric relaxation. 8. Taken together, these findings suggest that gastric distension-induced pyloric relaxation is mediated via a vago-vagal reflex and NO release. Acute hyperglycaemia stimulates hypothalamic NPY release, which, acting through the Y1 receptor, inhibits gastric distension-induced pyloric relaxation in rats exposed to acute elevations in blood glucose concentrations.

Effects of adrenalectomy and adrenal enucleation on liquid gastric emptying in rats

The effects of adrenalectomy and adrenal enucleation on liquid gastric emptying were studied in male Wistar rats that were adrenalectomized, adrenal enucleated (AE) or sham operated (SH). The animals in the first group had free access to a 1% NaCl solution (ADS), while the animals in the second and third groups were divided into two subgroups, which ingested either tap water (AEW, SHW) or 1% NaCl solution (AES, SHS). The gastric emptying study was performed on the 16th post-operative day. Three test meals labeled with phenol red (6 mg/dl) were used (0.9% NaCl, 1.8% NaCl and 5% glucose). Percent gastric retention was determined 10 min after orogastric infusion of the NaCl test meals and 15 min after the glucose meal. Gastric retention of the ADS subgroup was significantly lower (P<0. 01) (median = 19.8% vs 25.5% for SHW, vs 31.9% for SHS, vs 25.7% for AEW, and vs 27.1% for AES) for the 0.9% NaCl test meal and for the 1. 8% NaCl test meal (33.5% for ADS vs 47.5% for AEW and 50.6% for AES). When 5% glucose was used as a test meal, gastric retention was similar for all subgroups. These results suggest that ablation of the adrenal cortex results in increased gastric emptying of an isosmolar NaCl meal.

Does the route of feeding modify gastric emptying in rats?

BACKGROUND

It has been shown that the pattern of previous nutrient intake can influence gastric emptying. However, the effect of the absence of enteral stimulation in the setting of a normal energy supply on gastric emptying has not been examined. The aim of this study was to determine whether the absence of enteral stimulation during total parenteral nutrition (TPN) could modify gastric emptying in rats.

METHODS

Two experiments were performed. First, gastric emptying of a peptone meal was compared between rats receiving TPN, oral liquid diet (same solution as TPN), or regular diet (control group) for 10 days. In the second experiment, gastric emptying of two test meals (40% peptone and 25% glucose) was studied before and after rats received TPN or intragastric nutrition (same solution as TPN) for 10 to 12 days.

RESULTS

In experiment 1, gastric emptying of 40% peptone in the TPN and liquid diet groups was slower than that in the control group. This difference was significant between the TPN group and the control group (p < .01) but not between the liquid diet and control groups (p = .076). Gastric emptying of this meal in the TPN and liquid diet groups was similar. In experiment 2, no difference in gastric emptying of 40% peptone or 25% glucose was found between rats receiving TPN and those receiving intragastric nutrition for 10 to 12 days.

CONCLUSIONS

The composition of diet not the route of feeding is important in the modification of gastric emptying by the pattern of previous nutrient intake.

Inhibitory neural pathway regulating gastric emptying in rats

The relaxation of the pylorus is one of the most important factors for promoting gastric emptying. However, the role of inhibitory neurotransmitters in the regulation of pyloric relaxation and gastric emptying remains unclear. In this study, we investigated the effects of NO biosynthesis inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), and calcium dependent potassium channel blocker, apamin, on vagal stimulation-induced pyloric relaxation and gastric emptying in rats. Sodium nitroprusside (SNP), adenosine 5'-triphosphate (ATP), vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) caused pyloric relaxations in a dose dependent manner in vivo. Apamin (120 microg/kg) significantly reduced ATP and PACAP-induced pyloric relaxations without affecting SNP- or VIP-induced relaxations. Vagal stimulation (10 V, 1 ms, 1-20 Hz)-induced pyloric relaxation was significantly inhibited by L-NAME (10 mg/kg). The combined administration of L-NAME and apamin almost completely abolished vagal stimulation-induced pyloric relaxation. L-NAME and apamin significantly increased spontaneous contractions in the antrum, pylorus and duodenum. Increased motility index by L-NAME and apamin was significantly higher in the pylorus and duodenum, compared to that of antrum. L-NAME and apamin significantly delayed liquid gastric emptying. These results suggest that besides NO, probably ATP and PACAP, act as inhibitory neurotransmitters in the rat pylorus and regulate gastric emptying.

Effects of escins Ia, Ib, IIa, and IIb from horse chestnuts on gastric emptying in mice

Inhibitory effects of the saponin fraction and its principal constituents, escins Ia, Ib, IIa, and IIb, from horse chestnuts on gastric emptying were investigated in mice loaded with a non-nutrient or nutrient meal. The saponin fraction and escins Ia-IIb inhibited gastric emptying of a 1.5% carboxymethyl cellulose sodium salt (CMC-Na) meal by 11.1-54.2% (12.5-200 mg/kg). Escins Ia-IIb (50 mg/kg) also inhibited gastric emptying of a 40% glucose meal by 21.1-23.5% except for escin Ia, a milk meal by 18.4-33.1%, and a 30% ethanol meal by 13.5-15.9%. The effects of escins Ia-IIb on gastric emptying of the CMC-Na meal were attenuated by pretreatment with streptozotocin (100 mg/kg, i.v.), capsaicin (75 mg/kg in total, s.c.), or insulin (1 U/kg, s.c.). The effect of insulin was reduced by glucose (2 g/kg, i.v.) which can directly nourish the brain, but not by fructose (2 g/kg, i.v.) which cannot be utilized by the brain. The effects of escins Ia-IIb (50 mg/kg) were overridden in 60% ethanol-loaded mice, in which the central nervous system was suppressed by ethanol. These results suggest that capsaicin-sensitive sensory nerves and central nervous system partly participate in the effects of escins Ia-IIb.

Structure-related inhibitory activity of oleanolic acid glycosides on gastric emptying in mice

We examined the effects of various oleanolic acid oligoglycosides obtained from traditional herbs on gastric emptying in non-nutrient meal- or nutrient meal-loaded mice. Test samples were given orally to fasted mice 0.5 h before loading of test meals. Oleanolic acid 3-O-monodesmosides [oleanolic acid 3-O-glucuronide (3, 12.5-50 mg/kg), momordin Ic (4, 25 and 50 mg/kg), momordin I (6, 12.5-50 mg/kg), and 28-O-deglucosyl-chikusetsusaponins IV (8, 12.5-50 mg/kg) and V (10, 50 mg/kg)] were found to show inhibitory effects on gastric emptying in 1.5% CMC-Na test meal-loaded mice. 4, 6, and 8 also inhibited gastric emptying in mice given 40% glucose test meal, milk test meal, and 60% ethanol test meal. 3 inhibited gastric emptying in mice given milk test meal or 60% ethanol test meal, but lacked significant inhibition in 40% glucose test meal-loaded mice. 10 (50 mg/kg) also slightly inhibited gastric emptying in milk test meal-loaded mice, but lacked the significant inhibition in mice given 40% glucose or 60% ethanol test meal. Whereas oleanolic acid 3,28-0-bisdesmosides [momordin IIc (5), chikusetsusaponins IV (7) and V (9)], oleanolic acid 28-O-monodesmoside [compound O (2)], and their common aglycon [oleanolic acid (1)] showed no such effects at dose of 50 mg/kg. 28-O-Deglucosyl-chikusetsusaponin V (10) showed a little inhibition in these experiments. These results indicate that both the 3-O-monodesmoside structure and 28-carboxyl group were confirmed to be essential for such activity, and the 28-ester glucoside moiety and 2'-O-beta-D-glucopyranoside moiety reduce the activity.