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Pancreatic fluid hypersecretion in rats after acute pancreatitis.

Pancreatic exocrine function was examined in rats during the early stage of acute pancreatitis induced by four subcutaneous injections of 20 micrograms/kg body weight of cerulein at hourly intervals. Basal pancreatic fluid secretion at 6 hr after the first of four cerulein injections was significantly elevated (27.6 +/- 3.7 vs 17.4 +/- 2.1 microliters/30 min in control, P < 0.01) and further increased with time, reaching the peak level at 24 hr (105.1 +/- 4.6 microliters/30 min). Intravenous infusion of loxiglumide (50 mg/kg body wt/hr), atropine (100 micrograms/kg body wt/hr), or anti-secretin serum did not modify the fluid hypersecretion observed at 24 hr after induction of acute pancreatitis. Loxiglumide, when given 30 min before the first cerulein injection, markedly reduced fluid secretion, but could not inhibit the fluid hypersecretion when applied after the last cerulein injection. Leakage of Evans blue dye into pancreatic juice was slightly but significantly increased in postpancreatitic rats compared with that in the control rats (1.30 +/- 0.17 vs 0.75 +/- 0.08 micrograms/ml, P < 0.01), whereas that in the pancreas was not different from the control rats. In vivo labeling with 5-bromo-2'-deoxyuridine showed active proliferation of acinar and ductular cells at 6 hr. In addition, the fluid was rich in chloride (137.1 +/- 2.5 at 24 hr vs 92.4 +/- 3.3 meq/liter in control, P < 0.01) but poor in bicarbonate concentration (39.0 +/- 2.0 at 24 hr vs 46.5 +/- 1.9 mmol/liter in control, P < 0.01), indicating acinar cell secretion. These results indicate that pancreatic fluid secretion during the early stage of acute pancreatitis induced by supramaximal doses of cerulein was markedly increased not by CCK-, secretin-, or cholinergic-dependent mechanisms but probably by acinar cell proliferation.

Acute Disease↗

Role of CCK(A) receptors in postprandial lower esophageal sphincter function in morbidly obese subjects.

To reduce weight, some morbidly obese patients are treated with an intragastric balloon, often resulting in increased reflux symptoms. As transient lower esophageal sphincter relaxations (TLESRs) are the major mechanism underlying reflux and can be reduced by cholecystokinin-A (CCK(A)) blockade, we hypothesized that the CCK(A)-receptor antagonist loxiglumide could reduce gastroesophageal reflux in these subjects. Postprandial manometric studies were performed in 12 obese subjects during infusion of placebo or loxiglumide. Before balloon placement, loxiglumide did not significantly reduce the rate of TLESRs but attenuated the postprandial decrease in LES pressure. After 10 weeks of balloon treatment, loxiglumide significantly reduced the rate of TLESRs. Postprandial LES pressure was significantly increased, whereas the meal-induced decrease in LES pressure was absent. Neither loxiglumide nor balloon placement affected gastroesophageal reflux. In conclusion, CCK(A) receptors play an important role in post-prandial LES pressure decrease and are involved in the reflex pathway underlying the triggering of TLESRs, at least after balloon placement.

Adult↗

A cholecystokinin-like hormone activates a feeding-related neural circuit in lobster.

The peptide hormone cholecystokinin (CCK) contributes to the production of feeding-related behaviour in mammals, but the mechanism by which it exerts its effects remains unclear. The gastric mill neural circuit of lobster is an experimentally accessible model system for studying the hormonal control of feeding-related behaviour. Composed of 11 identified neurons, this circuit produces rhythmic movement of teeth within the stomach. We have previously shown that the gastric mill motor pattern can be modulated by a cholecystokinin-like peptide in vitro. We report here that (1) after feeding, levels of CCK-like peptide in haemolymph increase with the activation of the gastric mill, (2) injections of CCK activate the gastric mill, and (3) a specific CCK antagonist inhibits feeding-induced gastric mill activity. This neatly demonstrates a casual link between in vivo release of a peptide hormone and activation of a neural circuit.

Animals↗

Role of cholecystokinin in dietary fat-promoted azaserine-induced pancreatic carcinogenesis in rats.

The role of cholecystokinin in dietary fat-promoted pancreatic carcinogenesis was investigated in azaserine-treated rats, using lorglumide, a highly specific cholecystokinin-receptor antagonist. The animals were killed 8 months after the start of treatment. Cholecystokinin, but not dietary unsaturated fat, increased pancreatic weight. Rats treated with cholecystokinin developed more acidophilic atypical acinar cell nodules, adenomas and adenocarcinomas than control animals. Rats maintained on the high-fat diet developed significantly more adenomas and adenocarcinomas than controls given a diet low in unsaturated fat. Lorglumide largely inhibited the enhancing effect of cholecystokinin, but not of dietary fat, on pancreatic carcinogenesis indicating that it is unlikely that the promoting effect of dietary unsaturated fat on pancreatic carcinogenesis is mediated via cholecystokinin.

Animals↗

Inhibitory effect of a cholecystokinin antagonist on pancreatic carcinogenesis after pancreatobiliary diversion.

The role of cholecystokinin (CCK) has been explored in pancreatic carcinogenesis following pancreatobiliary diversion (PBD), using the specific CCK receptor antagonist CR-1409. Male Wistar rats (n = 80) weighing 70-100 g were given weekly i.p. injections of azaserine (30 mg kg-1 week-1) for 3 consecutive weeks. One week later animals were randomised to receive either PBD or sham PBD and thereafter to receive s.c. injections of either saline or CR-1409 (10 mg kg-1 day-1, 5 days a week). Six months after operation surviving rats were killed as follows: sham + saline 20, PBD + saline 19, sham + CR-1409 14, PBD + CR-1409 11. Cardiac blood was taken for CCK assay and the pancreas was excised for wet weight measurement and quantitative estimation of atypical acinar cell foci (AACF), the precursor of carcinoma. PBD reduced median body weight (3-20% less than shams) but trebled the absolute and relative pancreatic weights (P < 0.001). CR-1409 blunted this adaptive response to PBD, reducing absolute pancreatic weight by 35% (P < 0.005). PBD quadrupled circulating CCK concentrations, regardless of the antagonist treatment. Acidophilic AACF occurred only in rats with PBD. CR-1409 markedly reduced the number of observed acidophilic AACF by 90% (P < 0.001) and the number of foci per pancreas by 93% (P < 0.001). Moreover, CR-1409 reduced the mean focal diameter of each lesion by 18% (P < 0.005), the mean focal volume by 58% (P < 0.05) and the percentage of pancreas occupied by acidophilic foci by 95% (P < 0.001). PBD enhances pancreatic carcinogenesis by causing hypercholecystokininaemia, and CR-1409 largely inhibits this enhancement.

Animals↗

Reversal of tolerance to the antitransit effects of morphine during acute intestinal inflammation in mice.

1. The aim of investigation was to establish and compare the reversibility of tolerance to the antitransit effects of morphine by three different procedures: (a) acute inflammation of the gut, (b) lorglumide a cholecystokininA (CCKA) receptor antagonist, or (c) MK-801, an N-methyl-D-aspartate (NMDA) receptor ion channel blocker. The type of interaction between morphine and lorglumide or MK-801 on the inhibition of gastrointestinal transit (GIT) in naive animals was also evaluated. 2. Male Swiss CD-1 mice were implanted with 75 mg of morphine base or placebo pellets. Gastrointestinal transit was assessed with a charcoal meal and results expressed as % inhibition of GIT. Inflammation was induced by the intragastric (p.o.) administration of croton oil (CO), while controls received castor oil (CA) or saline (SS). Morphine was administered by subcutaneous (s.c.) or intracerebroventricular (i.c.v.) injection, to naive and tolerant animals treated with CO, CA or SS. Dose-response curves for s.c. morphine were also performed in naive and tolerant mice receiving 5.2 or 7.4 nmol (s.c.) lorglumide or MK-801, respectively. 3. The ED50 values for inhibition of GIT by s.c. morphine were: 45.9 +/- 2.7 and 250.1 +/- 3.1 nmol in naive and tolerant animals, respectively, demonstrating a five fold decrease in the potency of morphine. In naive animals, inflammation (CO) decreased the ED50 of morphine three times (14.4 +/- 2.2 nmol). However, no tolerance to s.c. morphine (ED50 16.4 +/- 2.6 nmol) was manifested during intestinal inflammation. After i.c.v. administration, a similar degree of tolerance to morphine was observed (4.8 fold decrease in potency). Intestinal inflammation had no effect on the ED50 values of i.c.v. morphine in naive and tolerant animals, showing that reversal of tolerance is related to local mechanism/s. Mean values for intestinal pH were 6.9 +/- 0.04 and 6.2 +/- 0.04 in SS and CO treated mice, respectively. In addition, morphine was 74 times more potent by the i.c.v. than by the s.c. route (naive-SS). 4. Morphine and lorglumide interacted synergistically in naive animals; in addition, the administration of lorglumide reversed tolerance to s.c. morphine. No interaction (additivity) was observed in naive animals when morphine and MK-801 were administered in combination. However, the drug completely reversed tolerance to the antitransit effects of morphine. 5. The present investigation shows that acute inflammation of the gut reverses tolerance to the antitransit effects of s.c. morphine by a peripheral mechanism. Qualitatively similar results were obtained after the administration of lorglumide or MK-801. Our results suggest that a local decrease in pH could play an important role during inflammation, while antagonism of endogenous compensatory systems would explain the reversal of tolerance induced by lorglumide or MK-801.

Acute Disease↗

Anxiogenic effect of cholecystokinin in the dorsal periaqueductal gray.

Systemic administration of cholecystokinin (CCK) fragments produces anxiogenic effects. The dorsal periaqueductal gray (dPAG) has been related to anxiety and panic reactions. The objective of this study was to investigate a possible anxiogenic effect of CCK-8 microinjected into the dPAG. At 10 min after the last microinjection (0.5 microl) into the dPAG male Wistar rats (N=7-17) were tested in the elevated plus-maze, an animal model of anxiety. The following treatments were tested alone or in combination: sulfated CCK-8 (CCK-8s, 0.5-1 microg), PD 135158 (N-methyl-D-glucamine, 0.1 microg), a CCK-2 receptor antagonist, lorglumide (0.1-0.3 microg), a CCK-1 receptor antagonist. In addition, Fos immunohistochemistry was performed in rats (n=3-4) treated with CCK-8s (1 microg) alone or in combination with PD 135158 (0.1 microg). CCK-8s produced anxiogenic-like effect, decreasing the percentage of time spent in open arm (saline=30.3+/-6.6, CCK 0.5 microg=15.2+/-1.8; CCK 1 microg=14.6+/-2.1). This effect was prevented by pretreatment with PD 135158, but not by lorglumide. CCK-8s injected into the dPAG induced Fos immunoreactivity in several brain areas related to defensive behavior, including the PAG, median, and dorsal raphe nuclei, superior colliculus, lateral septal nuclei, medial hypothalamus, and medial amygdala. This effect was also prevented by pretreatment with PD 135,158. These results suggest that CCK-8s, acting on CCK-2 receptors, may modulate anxiety reactions in the dPAG.

Analysis of Variance↗

Bombesin reduces food intake after a preload in man by a cholecystokinin-independent mechanism.

1. A double-blind study was undertaken to determine whether the infusion of bombesin inhibits the intake of a carbohydrate-rich meal, consumed 15 min after a 300 ml banana shake, in nine lean healthy subjects and whether the possible inhibition of food intake by bombesin is mediated by cholecystokinin. 2. The amount of food eaten during infusion of bombesin (267 +/- 60 g) and bombesin combined with the cholecystokinin-receptor antagonist loxiglumide (269 +/- 39 g) was slightly (P = 0.09) less than during saline infusion (384 +/- 40 g). In addition, preprandial feelings of hunger were significantly less during infusion of both bombesin and bombesin combined with loxiglumide. 3. In conclusion, infusion of bombesin tends to inhibit the intake of a carbohydrate-rich meal after a preload by a cholecystokinin-independent mechanism.

Adult↗

The effect of cholecystokinin antagonism on postprandial lower oesophageal sphincter function in asymptomatic volunteers and patients with reflux disease.

BACKGROUND: Postprandial acid reflux is thought to be mediated by the increase in transient lower oesophageal sphincter relaxations (TLOSR) frequency and fall in lower oesophageal sphincter (LOS) pressure seen after ingestion of a meal. Studies in animals and healthy volunteers suggest that cholecystokinin (CCK) may play a role. AIM: To study the role of CCK in postprandial LOS function using the CCK antagonist loxiglumide. SUBJECTS: 10 asymptomatic volunteers (7 male, 20-29 years) and 9 patients with symptomatic gastro-oesophageal reflux (4 male, 33-66 years). METHODS: Oesophageal, LOS and gastric pressure and oesophageal pH readings were recorded for 1 h before and 2 h after intragastric infusion of a 200 kCal, 300 mL long chain triglyceride meal. Each subject underwent two studies and received intravenous loxiglumide or placebo infusion in randomized order. RESULTS: During placebo infusion, postprandial LOS pressure fell [volunteers: 17 (9-31) to 7 (1-19) mmHg (P < 0.01), patients: 15 (6-26) to 9 (2-21) mmHg (P=0.02)] and TLOSR frequency increased [volunteers: 0 (0-1) to 2 (0-7) per hour (P=0.01), patients: 0 (0-3) to 2 (0-10) per hour (P=0.03)]. Loxiglumide infusion attenuated the postprandial fall in LOS pressure and the postprandial increase in TLOSR frequency [volunteers: 0 (0-3) per hour (P=0.04 vs. placebo), patients: 0 (0-2) per hour (P=0.03 vs. placebo)], but it had only modest effects on postprandial acid exposure [volunteers: placebo 45 (0-1725) vs. loxiglumide 0 (0-443) seconds (N.S.), patients: placebo 60 (0-3442) seconds vs. loxiglumide 31 (0-1472) seconds (N.S.)]. CONCLUSIONS: Loxiglumide inhibits TLOSR and attenuates the fall in LOS pressure following a meal, but has only modest effects on postprandial gastro-oesophageal acid reflux.

Adult↗

Transient lower oesophageal sphincter relaxations--a pharmacological target for gastro-oesophageal reflux disease?

The oesophago-gastric junction functions as an anti-reflux barrier preventing increased exposure of the oesophageal mucosa to gastric contents. Failure of this anti-reflux barrier results in gastro-oesophageal reflux disease, and may lead to complications such as oesophagitis, Barrett's oesophagus and eventually oesophageal carcinoma. Recent studies have suggested that transient lower oesophageal sphincter relaxation is the main mechanism underlying gastro-oesophageal reflux. It involves a prolonged relaxation of the lower oesophageal sphincter, mediated by a vago-vagal neural pathway, synapsing in the brainstem. Several drugs, such as atropine, baclofen and loxiglumide, have been shown to reduce the rate of transient lower oesophageal sphincter relaxations and concomitantly the number of reflux episodes. These findings illustrate that transient lower oesophageal sphincter relaxations may represent a potential new target for the pharmacological treatment of gastro-oesophageal reflux disease. It is possible that the reduction in the number of transient lower oesophageal sphincter relaxations may also contribute to the beneficial effect of fundoplication and new endoscopic anti-reflux procedures. It should be emphasized, however, that other factors, such as low lower oesophageal sphincter pressure, the presence of a hiatal hernia and impaired oesophageal peristalsis, are also of great importance. Therefore, whether the targeting of transient lower oesophageal sphincter relaxations is the 'golden bullet' in anti-reflux therapy remains to be proven, as evidence of an effective control of gastro-oesophageal reflux in reflux patients is still lacking.

Atropine↗

CCK-1 receptor blockade for treatment of biliary colic: a pilot study.

BACKGROUND: Loxiglumide is a potent and selective cholecystokinin-1 (CCK-1) receptor antagonist able to inhibit gall-bladder contraction. AIM: To assess the effect of CCK-1 receptor blockade on the pain of patients with biliary colic. PATIENTS AND METHODS: Fourteen patients with biliary colic but no suspicion for acute cholecystitis, were randomly and blindly assigned to loxiglumide (50 mg i.v.) or hyoscine-N-butyl bromide (20 mg i.v.) treatment. Pain intensity was monitored by a Visual Analogue Scale. Patients with less than 80% response at 30 min, were retreated with a second injection of the same compound. RESULTS: Reduction in pain score (mean +/- S.E.M.) was faster and significantly greater in patients treated with loxiglumide (n = 7) than in controls (n = 7): 88 +/- 7% vs. 47 +/- 12% after 20 min, P < 0.05; 92 +/- 6% vs. 49 +/- 13%, after 30 min, P < 0.05. Only one of seven patients treated with loxiglumide needed a second injection at 30 min (vs. six of seven controls, P < 0.05). No adverse effect was observed after either treatment. CONCLUSIONS: Loxiglumide is highly effective in obtaining pain relief in patients with biliary colic. The analgesic effect of CCK-1 receptor blockade is superior to that of a conventional anticholinergic treatment.

Adolescent↗

Intestinal phase of human antro-pyloro-duodenal motility: cholinergic and CCK-mediated regulation.

In this study the muscarinic receptor antagonist atropine and the cholecystokinin (CCK)-A receptor antagonist loxiglumide were used to investigate the relative importance of cholinergic and CCK-mediated regulation of intestinal phase antro-pyloro-duodenal motility. Plasma levels of gastrointestinal hormones [pancreatic polypeptide (PP), gastrin, CCK] were concomitantly determined to estimate biological potency of the doses of the receptor antagonists. In eight healthy male volunteers, a 30-min basal interdigestive period was followed by duodenal perfusion of a mixed liquid meal for 150 min at 1.6 kcal min-1 against a background of saline or atropine (5 micrograms kg-1 h-1) or loxiglumide (10 mg kg-1 h-1). Antropyloro-duodenal motility was continuously monitored with a sleeve straddling the pylorus. Against a background of saline, duodenal nutrients persistently stimulated isolated pyloric pressure waves. After 60 min, the initially low antral and duodenal contraction rates increased. In the fed state, atropine reduced total number of antral contractions and integrated motility index by 73% (P < 0.01) and 76% (P < 0.005), total number of pyloric contractions and integrated motility index by 43% and 50% (P < 0.05) with inhibition increasing over time. It did not alter duodenal contraction frequency but diminished duodenal motility index by 39% (P < 0.05) owing to a reduction in amplitude and duration of contractions. Loxiglumide decreased total numbers of antral, pyloric and duodenal contractions by 44% (P < 0.05), 74% (P < 0.005) and 41% (P < 0.005) respectively. It reduced cumulative antral, pyloric and duodenal motility indexes by 60% (P < 0.01), 80% (P < 0.01) and 61% (P < 0.05) respectively. Atropine fully abolished PP release to duodenal nutrients whereas loxiglumide reduced it by 60% (P < 0.05). Both atropine and loxiglumide enhanced gastrin release whereas only loxiglumide markedly stimulated CCK release. We conclude that both cholinergic input and endogenous CCK are major stimulatory regulators of antro-pyloroduodenal motility in the intestinal phase. There appears to be a regional heterogeneity of cholinergic and CCK control. Cholinergic input predominates in the antrum. Both systems are equipotent at the pylorus. CCK predominates in the duodenum. We suggest that CCK primarily interacts with receptors on cholinergic neurons in the antropyloric region and primarily affects smooth muscle receptors in the duodenum.

Acetylcholine↗

Pharmacological and molecular characterization of muscular cholecystokinin receptors in the human lower oesophageal sphincter.

In vitro cholecystokinin (CCK) contracts the human lower oesophageal sphincter by stimulating muscular receptors. The aim of this study was to characterize the muscular CCK receptor subtypes in the human lower oesophageal sphincter. Twenty-five circular strips from six patients were studied. RNA was extracted, reverse transcribed, and cDNAs were amplified with primers for human CCK-A and B receptors. The potency of the contraction induced by CCK-8, desulphated CCK-8, and gastrin-I, and the effect of the CCK-A (loxiglumide and SR 27897) and the CCK-B (YM022 and L-365 260) specific receptor antagonists were compared. Both CCK-A and CCK-B receptor mRNAs were found in functional lower oesophageal sphincter strips. The potency of the CCK-8 concentration-dependent contraction was two and three orders of magnitude higher than that of desulphated CCK-8 and gastrin-I, respectively. The CCK-8-induced contraction was blocked by the CCK-A receptor antagonists loxiglumide (IC50 11 micromol L-1) and SR 27897 (IC50 74 nmol L-1) but not by CCK-B receptor antagonists (1 micromol L-1). Our data suggest that, although the human lower oesophageal sphincter expresses both CCK-A and CCK-B receptors, the contractile effect of CCK-8 on the circular muscle is mainly due to the activation of CCK-A receptors.

Adult↗

Effect of cholecystokinin-A receptor blockade on postprandial insulinaemia and gastric emptying in humans.

Our aim was determine the relationship between cholecystokinin (CCK)-A receptor blockade, glucose levels, insulin secretion and gastric emptying in humans, and to assess the effect of CCK-A blockade on pancreatic polypeptide secretion. After a 12-h fast, six healthy volunteers were given [99mTc]iminodiacetic acid monosodium salt (IDA) intravenously (5 mCi). One hour later they were offered a 577 kcal liquid meal containing [99mTc]diethylenetriaminepentaacetic acid (DTPA) (2 mCi) and glucose (105 g). Scintigraphic gastric and gallbladder activity, and plasma glucose, insulin and pancreatic polypeptide responses were monitored. In a second experiment, a continuous intravenous infusion of loxiglumide (7.5 mg kg h(-1)) was started 60 min before and continued until 120 min after test meal ingestion to block the CCK-A receptors. Gallbladder emptying was blocked by loxiglumide. Loxiglumide accelerated gastric emptying, increased insulin secretion without alteration of glucose profiles, and abolished all phases of the postprandial pancreatic polypeptide response. Blockade of peripheral CCK-A receptors accelerates gastric emptying of liquids with an increase in postprandial insulin levels. The lack of changes in glycaemia suggests that alternative homeostatic mechanisms also control postprandial glucose levels. Inhibition of pancreatic polypeptide release may reflect an independent effect of loxiglumide on vagal control involved in pancreatic polypeptide release.

Adult↗

Antianalgesic action of dynorphin A mediated by spinal cholecystokinin.

Previous work indicates that the antianalgesic action of pentobarbital and neurotensin administered intracerebroventricularly in mice arises from activation of a descending system to release cholecystokinin (CCK) in the spinal cord where CCK is known to antagonize morphine analgesia. Spinal dynorphin, like CCK, has an antianalgesic action against intrathecally administered morphine. This dynorphin action is indirect; even though it is initiated in the spinal cord, it requires the involvement of an ascending pathway to the brain and a descending pathway to the spinal cord where an antianalgesic mediator works. The aim of the present investigation was to determine if the antianalgesic action of intrathecal dynorphin A involved spinal CCK. All drugs were administered intrathecally to mice in the tail flick test. Morphine analgesia was inhibited by dynorphin as shown by a rightward shift of the morphine dose-response curve. The effect of dynorphin was eliminated by administration of the CCK receptor antagonists lorglumide and PD135 158. One hour pretreatment with CCK antiserum also eliminated the action of dynorphin. On the other hand, the antianalgesic action of CCK was not affected by dynorphin antiserum. Thus, CCK did not release dynorphin. Both CCK and dynorphin were antianalgesic against DSLET but not DPDPE, delta 2 and delta 1 opioid receptor peptide agonists, respectively. The results suggest that the antianalgesic action of dynorphin occurred through an indirect mechanism ultimately dependent on the action of spinal CCK.

Analgesia↗

Cholecystokinin-A receptors modulate gastric sensory and motor responses to gastric distension and duodenal lipid.

BACKGROUND & AIMS: The combination of duodenal lipid and gastric distention induces meal-like fullness followed by nausea in healthy subjects. The aim of this study was to assess the role of cholecystokinin (CCK) A receptors in these changes using a CCK-A antagonist loxiglumide. METHODS: Twelve healthy subjects were studied on four occasions, during which either 0.9% saline or 20% Intralipid was infused intraduodenally on two occasions each (1 mL/min) while the proximal stomach was distended with air (100 mL/min). During each duodenal infusion, subjects received intravenous loxiglumide (10 mg.kg-1.h-1) on 1 day and placebo on the other. Intragastric pressure changes were recorded, and the subjects reported gastric sensations (fullness, nausea). RESULTS: Loxiglumide did not influence gastric motility or sensitivity during duodenal saline infusion. Duodenal lipid reduced gastric tonic and phasic pressure activity during distensions and induced meal-like fullness and nausea; sensations were reported at similar volumes but lower intragastric pressures (P < 0.001 vs. saline). Loxiglumide partially restored gastric tonic and phasic activity during lipid infusion, reduced the occurrence of meal-like fullness and nausea, and increased the pressures at which sensations were reported (P < 0.001 vs. placebo). CONCLUSIONS: CCK-A receptors are involved in the induction of meal-like fullness and nausea associated with intraduodenal lipid and gastric distention.

Adult↗

Effects of lorglumide and atropine on MgSO(4)-induced gallbladder emptying in conscious dogs.

The aim of the study was to examine the possible involvement of cholecystokinin (by lorglumide) and cholinergic mechanisms (by atropine) in magnesium sulphate (MgSO(4))-induced gallbladder contraction of conscious dogs. The gallbladder (GB) volume was determined by ultrasonography. The optimal dose of 80 mg kg(-1)of MgSO(4)was determined from a MgSO(4)dose-response curve using doses of 10, 20,40, 80, 120 mg kg(-1). The largest dose of MgSO(4)was less effective than the optimal dose. Peak gallbladder contraction (32 per cent) was achieved at 30 minutes. Atropine (50 microg kg(-1)s.c.) or lorglumide (1 mg kg(-1)p.o.) fully prevented GB contraction. In conclusion, supraoptimal doses of MgSO(4)have a diminishing effect. The sustained contraction of the gallbladder in response to the optimal dose of MgSO(4)can be explained by an additive effect of the cholecystokinin release and a cholinergic trigger mechanism. Ultrasonography and MgSO(4)stimulation proved to be a valuable technique for examination of gallbladder motility.

Animals↗

Stimulative effects of saponin from kikyo-to, a Japanese herbal medicine, on pancreatic exocrine secretion of conscious rats.

Our previous report stated that kikyo-to, a Japanese herbal medicine, consisting of the roots of Platycodon grandiflorum and Glycyrrhiza sp., stimulates the pancreatic exocrine secretion of conscious rats. The present study focused on the effective components of kikyo-to and the mechanism of stimuli to pancreatic secretion of rats. When 10 to 100 mg of platycodin D, a saponin from the root of Platycodon grandiflorum, was intragastrically administered, the pancreatic secretion of rats was stimulated. At the same time, the plasma CCK concentration increased. On the other hand, the stimulative effects of glycyrrhizin, a saponin from the root of Glycyrrhiza sp. were weak compared to platycodin D. The effects of 10 mg/kg of platycodin D on pancreatic secretion were inhibited by loxiglumide (50 mg/kg, i.g.), a CCK receptor antagonist. In contrast, the suppressive effect of atropine (300 micrograms/kg/h, i.v.) on pancreatic secretion was reduced by administering 10 mg/kg of platycodin D. In addition, up to 1 mM of platycodin D did not inhibit the trypsin activities in vitro. In conclusion, kikyo-to serves to stimulate pancreatic exocrine secretion mainly because platycodin D causes gastrointestinal hormones, particularly, CCK to be released from the duodenum.

Animals↗