Digestion

doi: 10.1159/000199334pmid: N/A

Schemann, M.; Ehrlein, H.-J.

doi: 10.1159/000199335pmid: 3488934

We investigated in conscious dogs the effects of intravenously administered 5-hydroxytryptophan (5-HTP) and cisapride on the postprandial jejunal mechanical activity by means of six closely spaced extraluminal strain gauge transducers. Drugs were given after administration of a nutrient meal. 5-HTP was given additionally after the administration of a noncaloric cellulose meal. Computer assistance was used to determine the temporal and spatial relationship of contractions and thereby to evaluate the length of spread of contractile waves. Both substances increased the propulsive activity, the contractile force and the motility index and fastened the transit rate of digesta. 5-HTP exhibited the most potent effect when given after administration of the nutrient meal.

Jenkins, S.A.; Baxter, J.N.; Devitt, P.; Taylor, I.; Shields, R.

doi: 10.1159/000199336pmid: 3743909

The effects of varying rates of alcohol infusion (0.015–0.12 mg/g body weight/ min) on hepatic haemodynamics were studied in male Wistar rats. An infusion of 0.015 mg/g body weight/min alcohol had no significant effect on portal pressure (PP) or wedged hepatic venous pressure (WHVP). However, increasing rates of infusion of alcohol (0.03–0.12 mg/g body weight/min) progressively increased PP and WHVP, the maximum increase in PP occurring following an infusion of 0.12 mg/g body weight/min (6.5 ± 0.5 – 10.3 ± 0.6 mm Hg). The effect of varying rates of alcohol infusion on portal venous flow and liver blood flow was biphasic. Thus following an infusion of 0.03 mg/g body weight/min alcohol, liver blood flow (40.6 ± 4.9–54.3 ± 5.8 ml/100g/min) and portal venous flow (28.6 ± 2.9–41.3 ± 4.1 ml/min) were increased. However, following infusions of 0.06 and 0.12 mg/g body weight/min alcohol, liver blood flow and portal venous flow were decreased. The results suggest that previous conflicting reports on the effects of alcohol on hepatic haemodynamics may be related to the dose of alcohol administered.

D’Agostino, Luciano; Ciacci, Carolina; Capuano, Gaetano; Daniele, Bruno; D’Argenio, Giuseppe; Barone, Maria Vittoria; Rodinò, Stefano; Budillon, Gabriele; Mazzacca, Gabriele

doi: 10.1159/000199337pmid: 3091435

After injection of an intravenous bolus of heparin (15,000 IU) in two groups of subjects, 10 normal volunteers and 6 subjects with external biliary drainage, blood and urine samples were collected; in the latter group bile samples were collected also. All samples were assayed for diamine oxidase (DAO). Persistently high values of this enzyme were found in plasma of both populations after heparin stimulation, while no increase in enzymatic activity was detected in bile and urine. In order to confirm and support the hepatic clearance of DAO, liver uptake of the enzyme derived from porcine kidney, human plasma and human placenta was studied by perfusion of isolated rat liver. Disappearance curves of the enzyme derived from three different sources showed a prompt liver uptake: activity decreased by about 50% in 10min (endocytic uptake) and a slower but constant reduction during the remaining 110 min of perfusion was observed. These data suggest the hypothesis of liver metabolism of plasma DAO.

Sidhu, G.S.; Garg, U.C.; Dhaunsi, G.S.; Bhari, S.K.; Ganguly, N.K.; Bhatnagar, R.

doi: 10.1159/000199338pmid: 3527833

The intestinal absorptive and digestive functions using the brush border membrane (BBM) vesicles were evaluated in guinea pigs receiving cholesterol-supplemented diet for 12 weeks. The Na⁺-gradient-dependent transport of D-glucose (p < 0.001), L-alanine and L-phenylalanine (p < 0.01) was decreased significantly the BBM of cholesterol-fed animals. The maximal velocity (Vmax) value of the sucrase and leucine aminopeptidase was decreased without any change in the affinity constant (Km) value, demonstrating that the enzyme contents were reduced in response to cholesterol-rich diet. However, both the Km and Vmax values of the alkaline phosphatase decreased markedly, suggesting that a new enzyme of increased substrate affinity had been formed due to intestinal adaptation of cholesterol load in diet. The present study demonstrated that cholesterol feeding caused a significant alteration in nutrients absorption, membrane enzymes and chemical composition of the small intestine.

Takeuchi, Koji; Ueki, Shigeru; Okabe, Susumu

doi: 10.1159/000199339pmid: 3743910

Mechanisms of antisecretory action of intragastric FPL-52694, a mast cell stabilizer, were investigated in anesthetized rats. In Schild’s rat preparation, intravenous FPL-52694 (10 mg/kg) significantly suppressed acid secretion in response to only tetragastrin (20 μg/kg, i.v.) (42.1 ± 19.4%), while intragastric application of FPL-52694 (100 mg/kg) for 30 min produced a marked, unequivocal inhibition (over 70%) in acid secretory responses to histamine (1 mg/kg, i.v.) and carbachol (2.5 μg/kg, i.v.) as well as tetragastrin. The inhibitory effect of intragastric FPL-52694 was confirmed in the lumen-perfused rats, where acid secretion (24–25 μmol/10 min) induced by intravenous infusion of histamine (8 mg/kg/h) was abolished for 1 h after exposure of the stomach for 30 min to this agent. Inhibition of histamine-stimulated acid secretion by intragastric FPL-52694 was much greater and lasted longer (2 h) as compared with xylocaine (4% solution), but significantly mitigated by pretreatment of the rats with subcutaneous administration of indomethacin (3 mg/kg). Furthermore, application of FPL-52694 but not of xylocaine to the stomach caused a reduction of transmucosal potential difference, an increase of luminal appearance of HCO₃^- (1–2 μmol/10 min), and an enhancement of H⁺ back-diffusion, although no damage was appreciated in the mucosa. These results suggest that antisecretory action of intragastric FPL-52694 may involve local mechanisms such as neutralization of acid with HCO₃^-, a loss of acid due to H⁺ back-diffusion, and inhibition of acid production mediated by endogenous prostaglandins, but is not related to the local anesthetic activity.

Konturek, S.J.; Bilski, J.; Tasler, J.; Konturek, J.W.; Bielański, W.; Kamińska, A.

doi: 10.1159/000199340pmid: 3091436

Duodenal secretion of HCO₃^- and luminal release of PGE₂ were measured in conscious dogs. The results show that the HCO₃^- secretion is closely correlated with the luminal release of PGE₂ and that both the HCO₃^- and the PGE₂ outputs increase dose-dependently after topical application of hydrochloric acid or arachidonic acid. Indomethacin reduced basal HCO₃^- and PGE2 release and prevented their increase in response to hydrochloric acid or arachidonic acid. We conclude that mucosal PGE₂ plays an important role in the alkaline secretion from the duodenum.

Siomiany, B.L.; Murty, V.L.N.; Carter, S.R.; Slomiany, A.

doi: 10.1159/000199341pmid: 2427379

The contribution of associated and covalently bound lipids to the viscosity of gastric mucus glycoprotein in healthy and cystic fibrosis (CF) individuals was investigated. While both preparations exhibited similar contents of protein and carbohydrate, the CF glycoprotein contained 1.3 times more associated lipids and 6 times more covalently bound fatty acids. The viscosity of CF mucus glycoprotein was about 1.8 times higher than that of normal glycoprotein. Extraction of associated lipids lead to 3-fold drop in the viscosity of CF glycoprotein and 5-fold drop in the case of normal glycoprotein. Removal of covalently bound fatty acids caused further 1.6-fold reduction in the viscosity of normal mucus glycoprotein and 6-fold in CF glycoprotein. The viscosity of the delipidated and deacylated CF mucus glycoprotein was only about 10% higher than that of the similarly treated normal glycoprotein. The results suggest that the elevated level of covalently bound and associated lipids is responsible for the increased viscosity of CF mucin.

Keinke, Oliver; Wulschke, Sabine; Ehrlein, Hans Jörg

doi: 10.1159/000199342pmid: 3743911

The effect of neurotensin (10 pmol/kg/min) on gastric emptying was investigated in 5 dogs. Gastroduodenal motility was recorded with strain-gauge transducers and induction coils, gastric emptying was measured radiographically. In the first 15 min, neurotensin abolished gastric emptying, reduced antral and duodenal contractions and diminished the pyloric opening and the duodenal lumen. Subsequently, antral and pyloric activity returned to control values. The emptying rate remained diminished due to segmenting contractions and a small lumen of the duodenum. Results suggest that neurotensin influences gastric emptying mainly by its long-lasting action on the duodenum.

doi: 10.1159/000199343pmid: N/A