sincalide and Alcoholism

Three-month-old female Wistar rats were fed with 20% alcohol in their drinking fluid over 6-17 mo using an interrupted feeding regimen. At different times, pancreatic acini were isolated by mild collagenase digestion. The concentrations of inositol-1,4,5-trisphosphate (1,4,5-IP3) were determined by a specific radioreceptor assay, before and at different times after stimulation with varying concentrations of CCK-8. CCK-induced dynamics of cytoplasmic calcium ([Ca2+]c) was investigated in acinar cells by confocal laser raster microscopy. Acinar alpha-amylase (Aml) secretion was measured as enzyme activity in the medium compared to the total activity in the suspension.. In 12-13-mo-old rats, the CCK-stimulated 1,4,5-IP3 formation in acini was found to be decreased compared to young rats (age 4 mo). In rats of the same age fed with ethanol from the age of 3 mo on, 1,4,5-IP3 concentrations in acini were higher and reached values comparable to those in young rats. Correspondingly, the CCK-induced [Ca2+]c dynamics in acini isolated from 9-mo-old rats was impaired compared to that of young rats but normal in aged, chronically alcohol-fed rats. Aml secretion under CCK stimulation, however, which was decreased in aged rats, was additionally impaired after alcohol feeding.. Chronic alcohol feeding modifies 1,4,5-IP3 formation, the [Ca2+]c dynamics of, and the Aml secretion of rat pancreatic acini in response to CCK stimulation. Obviously, the age-related impairment of 1,4,5-IP3 formation and [Ca2+]c dynamics is improved. In contrast, the decrease in Aml secretion of acini isolated from aged rats is more pronounced after long-term alcohol-feeding.

Topics: Aging; Alcoholism; alpha-Amylases; Animals; Calcium Signaling; Cytoplasm; Female; In Vitro Techniques; Inositol 1,4,5-Trisphosphate; Pancreas; Rats; Rats, Wistar; Sincalide

A "free choice" two-bottle drinking test paradigm was implemented in naive adult male Wistar rats, resulting in a clear identification of rats drinking mainly water (water-preferring, WP rats) and rats spontaneously drinking also a consistent amount of a solution of cocaine (0.5 mg/ml water, cocaine-drinking, CD rats) or ethanol 10% v/v (ethanol-drinking, ED rats). Low, selective doses (5 micrograms/kg) of the specific cholecystokinin (CCK)-A receptor antagonist L-364,718 largely reduced the intake of ethanol 10% of ED rats only. In contrast, low, selective doses of GV-150013 (5 micrograms/kg) reduced significantly the consumption of cocaine of CD rats only. These results indicate that the CCK-A or B receptors are selectively involved in the modulation of alcohol or cocaine intake, respectively, and suggest an involvement of the CCKergic system in the drug-seeking behavior. WP rats and CD rats were then prepared for ex vivo electro-neurochemical analysis by means of differential pulse voltammetry (DPV) with micro-biosensors to monitor catechol, 5-hydroxyindole and peptidergic oxidation signals in the nucleus accumbens (nAcc). In this area, the peptidergic signal appeared to be related to the oxidation of endogenous CCK, which basal levels resulted higher in ED and CD rats than WP rats. Thus, the hypothesis that the endogenous tone of the CCK system is higher in the ED and CD rats than in the WP rats is proposed, and is supported by the observation that treatment with CCK-5 (CCK receptor agonist) selectively induced the WP rats to drink alcohol or cocaine. The selective effect of the CCK-antagonists on reducing the drug intake of ED or CD rats further supports this view, as it suggests that CCK antagonists may modify the individual sensitivity towards drugs of abuse set by the stimulating effect of high endogenous CCKergic tone over CCK-B or CCK-A receptors in spontaneous ED or CD rats, respectively. Therefore, the present data indicate that: i) Free-choice models may reveal the presence of individual sensitivity to alcohol or cocaine in naive rats; ii) the dopaminergic system is involved within the reward state, while peptidergic (CCKergic) activities modulate the drug-seeking state (craving state); iii) the CCK system could be a new target in the study of the drug dependency phenomenon. In particular, the data imply a CCK-A receptor mechanism in the regulation of individual sensitivity towards ethanol and a CCK-B receptor mechanism in the regulation of i

Topics: Adamantane; Alcohol Drinking; Alcoholism; Animals; Benzodiazepinones; Cocaine; Cocaine-Related Disorders; Drinking; Male; Peptide Fragments; Phenylurea Compounds; Rats; Rats, Wistar; Receptor, Cholecystokinin A; Receptor, Cholecystokinin B; Receptors, Cholecystokinin; Sincalide

Brain cholecystokinin (CCK) receptors have been implicated in anxiety disorders and suicidal behaviour. We have examined the radioligand binding ability of CCK and benzodiazepine receptors in rat brain after long-term intermittent voluntary vs voluntary and forced low-dose ethanol exposure. During 58 weeks, one group of rats had a choice between ethanol and water as the drinking fluid for 24 hr each week. Another group of rats had the same weekly choice between ethanol and water, but at the end of each 24 hr choice period, ethanol (2.0 g/kg) was injected. During the second period of ethanol treatment, lasting for 32 weeks, both ethanol-treated groups had continuous free access to ethanol and water. These two treatments have previously been shown to induce partially different neurochemical alterations. In the present investigation, benzodiazepine receptor binding in the frontal cortex, hippocampus and striatum was similar in both ethanol treatment groups compared to controls. CCK receptor binding in the hippocampus and striatum did not differ between the three groups; however, in the frontal cortex, there was an increase in the apparent number of CCK binding sites in the group of rats submitted to voluntary plus forced ethanol exposure as compared to the control group or the voluntary intake group. These results suggest that long-term ethanol treatment may lead to alterations in brain CCK-ergic neurotransmission, but that the changes are specific to the treatment schedule.

Topics: Alcoholism; Animals; Binding, Competitive; Brain; Corpus Striatum; Dose-Response Relationship, Drug; Flunitrazepam; Frontal Lobe; Hippocampus; Male; Radioligand Assay; Rats; Rats, Sprague-Dawley; Receptors, Cholecystokinin; Receptors, GABA-A; Sincalide

In this study we examined the ability of intraperitoneal cholecystokinin COOH-terminal octapeptide (CCK-8; 0.2, 0.6, and 2.0 micrograms/kg) to suppress food intake in rats that had consumed a control diet, 6-8 g.kg-1.day-1 of ethanol (EtOH) in sucrose, or sucrose alone for 6 mo. Both the EtOH- and sucrose-fed rats developed significant dietary obesity. After 3 mo, the EtOH group was significantly more sensitive to CCK-8 than the sucrose and control groups, while the responses of the sucrose and control groups were comparable. In contrast, after 6 mo the EtOH and sucrose groups' response to CCK-8 was no longer significantly different. After 6 mo there were no significant differences in basal or postprandial plasma CCK-8 levels. The sucrose group had significantly higher basal insulin levels than the control and EtOH groups, and postprandial insulin levels, relative to basal, were significantly elevated in the EtOH group. Basal glucose levels did not differ among groups. Postprandial glucose levels (relative to baseline) were significantly lower in the EtOH group compared with the other groups and in fact never rose above baseline levels. These results are consistent with the hypothesis that EtOH, when taken on a chronic basis, increases the sensitivity to CCK-8.

Topics: Alcoholism; Animals; Anorexia; Blood Glucose; Cholecystokinin; Eating; Insulin; Male; Rats; Rats, Inbred Strains; Sincalide; Time Factors

Adverse effects observed in alcoholic rats are often attributed to alcohol per se. Alcoholic liver damage, however, can be avoided by modulating nutritional factors despite high blood alcohol concentrations. Hence, we examined the effect of blood alcohol concentration on pancreatic enzyme activity and release. Three liquid diets containing 36 and 18% of total energy derived from alcohol and protein, respectively, were fed. Each alcohol diet contained 11, 21 or 31% of energy from carbohydrate, and the fat concentration was appropriately adjusted. The control groups of rats (fed an isoenergetic liquid diet without alcohol) and the alcoholic groups of rats were maintained for 2 wk. The three groups of alcoholic rats consumed 13.3 +/- 2.3, 13.3 +/- 2.2 and 13.2 +/- 1.9 g/kg of alcohol daily, and their corresponding blood alcohol levels were 41.5 +/- 4.3, 55.4 +/- 8.9 and 44.6 +/- 2.2 mmol/L. Pancreatic acinar amylase activity in alcoholic rats was proportional to carbohydrate ingested, despite high blood alcohol concentrations; chymotrypsin and trypsin activities were unchanged. Acinar enzyme activities in control rats were similar. Furthermore, cholecystokinin-octapeptide-stimulated amylase release in alcoholic rats corresponded with the amylase concentration in acini, whereas stimulated trypsin output was unaltered in both control and alcoholic rats. These results demonstrate that neither alcohol ingestion nor high blood alcohol concentration affects the activities of pancreatic proteases and that the changes in the activity and release of amylase are related to the intake of carbohydrate.

Topics: Alcoholism; Amylases; Animals; Chymotrypsin; Dietary Carbohydrates; Dietary Fats; Energy Intake; Ethanol; Kinetics; Male; Pancreas; Rats; Rats, Inbred Strains; Sincalide; Trypsin

Carbohydrate consumption regulates pancreatic amylase synthesis in rats. The Lieber-DeCarli 36% alcohol diet employed in chronic alcohol studies and the isocaloric control diet contain 11 and 47% of total calories from carbohydrates, respectively. Young rats fed ad libitum the 36% ethanol diet for 2 weeks obtained 1.2 g/day of carbohydrate, whereas those pair-fed with control diet received 5.8 g/day. Rats fed the 36% ethanol diet and given an intramuscular injection of a solution of 1.5 g of glucose daily for 2 weeks received twofold greater amounts of carbohydrate than saline-injected controls (2.7 versus 1.2 g). These changes in carbohydrate intake produced proportionate changes in pancreatic amylase levels. The secretory responses to cholecystokinin-octapeptide (CCK8) of acini from control and glucose-injected rats were significantly higher compared with those in the saline-injected or noninjected alcohol groups. The blood alcohol levels in glucose-injected rats were markedly reduced compared with other alcohol groups (71.7 versus 274.9 mg/dl) despite similar amounts of ethanol ingestion daily (2.4 g) in the three groups. In vitro experiments with acini from rats fed a nutritionally optimal diet revealed that high pharmacologic concentrations of ethanol, while inducing basal secretion, inhibited CCK8-stimulated amylase secretion. These results indicate that: (a) the amount of alcohol consumption does not correlate with either the levels of blood alcohol or of pancreatic amylase; (b) the carbohydrate availability in rats regulates pancreatic amylase levels despite significant levels of alcohol in blood; (c) blood alcohol levels observed in vivo may not affect synthetic and secretory processes of amylase in pancreatic acini.

Topics: Alcoholism; Amylases; Animals; Carbohydrates; Glucose; Infusions, Parenteral; Male; Pancreas; Rats; Rats, Inbred Strains; Sincalide

The effects of sustained, high blood alcohol levels (216 +/- 120 mg/100 ml, S.D.) for 30 days on cholecystokinin (CCK)-mediated pancreatic exocrine function were studied in a rat model that achieves both maximally controlled, optimal nutrition and high alcohol intake (approximately 40.5% of total calories). In alcohol-fed rats, basal plasma levels of immunoreactive cationic trypsinogen (ICT) were reduced by 50% (P less than 0.05), but intravenous doses (0-30 IDU/kg/hr; 1 IDU = approximately 62.5 ng CCK-8) of cholecystokinin octapeptide (CCK-8) resulted in a 3-fold greater maximal concentration of ICT and an 80% steeper slope of the dose-response curve compared to those of pair-fed control animals. Basal plasma levels of amylase were not different in the two groups at basal conditions and did not change significantly following CCK-8 administration. In vitro studies with isolated pancreatic acini have shown that basal secretion of ICT into the media was similar in the two groups. However, ICT secretion in response to CCK-8 (30-3000 pM) was 2-fold greater in alcohol-fed rats than in pair-fed controls, resulting in a CCK-8 EC50 which was about half that of controls. On the contrary, the basal and maximal amylase secretion from acini isolated from alcohol-fed rats was reduced by 67 and 43%, respectively, causing a reduction in the magnitude of the response curve with almost identical EC50 and slopes. Despite the marked alterations in CCK-stimulated enzyme secretion, radioiodinated CCK-33 binding to receptors on acini isolated from both control and alcohol-fed rats was similar. Cellular concentrations of ICT and amylase, however, revealed similar patterns of alterations: 2 to 3-fold increase in ICT and 70% reduction in amylase in alcoholic acini compared to controls. These results indicate that the inverse changes in amylase and ICT secretions following continuous ethanol administration are probably due to differential effects on enzyme synthesis.

Topics: Alcoholism; Animals; Cholecystokinin; Ethanol; Male; Pancreas; Rats; Rats, Inbred Strains; Secretin; Sincalide; Time Factors; Trypsinogen

Previous studies have suggested that chronic alcohol consumption in man is associated with an increased secretion of pancreatic enzymes. Precise quantitation of the output of protein and trypsin in the interdigestive state has not been possible because of large variations and small volume of pancreatic juice. We utilized a multilumen, marker-perfused duodenal catheter to simultaneously monitor intraluminal pressures and collect mixed duodenal juice at the ligament of Treitz in five groups of patients: normal volunteers (group I), alcoholics without pancreatitis (group II), alcoholics who had recovered from acute pancreatitis (group III), alcoholics with chronic pancreatitis (group IV), and nonalcoholics who had recovered from acute pancreatitis secondary to biliary tract disease (group V). The output of trypsin and protein during 30 min of phase II and 60 min of CCK-OP 40 ng/kg/hr was determined in each group. The output of trypsin during phase II was 1.3 +/- 1.2 and 3.0 +/- 2.5 mg/kg/hr in groups II and III, respectively, compared to 0 +/- 0.1 in group IV (normal = 0.6 +/- 0.5). The outputs in group V were similar to normals. The output of protein during the interdigestive state was 15.7 +/- 13.7 mg/min in group III, compared to 4.5 +/- 3.6 in normals (group I). The duodenal contraction rate was 4.6 +/- 3.0 and 3.3 +/- 2.7 contractions/min in groups III and II, respectively (significantly greater than the normal rate of 2.2 +/- 1.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Alcoholism; Biliary Tract Diseases; Catheterization; Digestion; Duodenum; Fluoroscopy; Gastric Juice; Gastrointestinal Motility; Humans; Hydrogen-Ion Concentration; Pancreas; Pancreatic Juice; Pancreatitis; Pressure; Proteins; Sincalide; Sulfobromophthalein; Trypsin

A review of gallbladder scintigraphy in patients with potentially compromised hepatobiliary function revealed two groups in whom cholecystitis might be mistakenly diagnosed. In 200 consecutive hospitalized patients studied with technetium-99m-PIPIDA for acute cholecystitis or cholestasis, there were 41 alcoholics and 17 patients on total parenteral nutrition. In 60% of the alcoholics and 92% of those on parenteral nutrition, absent or delayed visualization of the gallbladder occurred without physical or clinical evidence of cholecystitis. A cholecystagogue, sincalide, did not prevent the false-positive features which presumably are due to altered bile flow kinetics related to alcoholism and parenteral nutrition. Four patients on parenteral nutrition undergoing cholecystectomy for suspected cholecystitis had normal gallbladders filled with jellylike viscous thick bile. A positive (nonvisualized or delayed visualized) gallbladder PIPIDA scintigram in these two populations should not be interpreted as indicating a need for cholecystectomy.

Topics: Alcoholism; Bile; Cholecystitis; Cholecystokinin; Cholestasis; False Positive Reactions; Gallbladder; Humans; Imino Acids; Organotechnetium Compounds; Parenteral Nutrition; Parenteral Nutrition, Total; Peptide Fragments; Radionuclide Imaging; Sincalide; Technetium