Bile in the stomach

Pepsinogen secretion in the intraluminally perfused stomach of narcotized rats was induced by electrical stimulation of the vagus nerve or intravenous injection of pentagastrin. Blockade of histamine H 2 receptors inhibited pepsinogen production induced by vagal stimulation by 35%, but caused only a 13% decrease in pentagastrin-stimulated pepsinogen secretion. Key Words: pepsinogen; vagus; pentagastrin; histaminePractically in all mammals, vagal cholinergic and gastrin effects on parietal cells of the stomach are mediated by histamine-producing cells [4]. Chief cells of the gastric mucosa producing pepsinogen are evolutionary similar to parietal cells [3,10] and functionally depend on their state. However, of mechanisms secretion, nervous and endocrine regulation in these cells differ considerably [5,6,11]. The data on the involvement of main secretagogues in the regulation of pepsinogen production are contradictory due to species specificities and peculiarities of experimental models [9,12]. The role of histamine in mediating vagal and gastrin effects on chief cells of the stomach remains unclear. Here we evaluated the role of cholinergic, gastrin, and histamine mechanisms in the regulation of pepsinogen secretion in the stomach of narcotized rats. MATERIALS AND METHODSExperiments were performed on 42 male SpragueDawley rats weighing 309• g and kept at 20+1~ under a 12-h light/dark schedule and ad libitum food supply (Rappolovo R50258-92). One day before operation, the animals were deprived of food, but had free access to water.The rats were narcotized with intraperitoneal injection of choral hydrate and urethane (800+ 100 mg/kg, Sigma). Isotonic NaC1 containing 3 mM NaHCO 3 and 2% glucose was administered intravenously (1 ml/h) to prevent acidosis and dehydration. The animals were heated on a temperature-controlled table with incandescent lamp. Heart rate (HR), blood pressure (BP), and rectal temperature were measured.After tracheotomy, catheterization of the right femoral artery and vein, and median laparotomy were carried out subdiaphragmatic vagotomy, gastric sympathectomy, and ligation of the left adrenal gland were conducted if required. The stomach was perfused with isotonic NaC1 at a flow rate of 0.7 ml/min, 37~ pH 6.0, and 0 mm Hg. The solution was administered through a catheter and removed via a perforated polyethylene tube introduced through a duodenal section into the pylorus. The peripheral end of the left subdiaphragmatic vagus nerve was demyelinated and stimulated with rectangular pulses (6 V, 1 msec, 8 Hz) delivered through silver electrodes for 10 min.Perfusate samples were taken at 15-min intervals using a fraction collector (LKB). Pepsinogen concen-0007-4888/00/0001-7525.00 9Kluwer Academic/Plenum Publishers

show abstract

“…Basal pepsinogen secretion in our experiments is consistent with the data obtained on alert animals and isolated mouse stomach (Table 1) [2,12].…”

Section: Resultssupporting

confidence: 93%

“…Exogenous histamine did not affect pepsinogen secretion in the stomach of awake rats [ 12] and even inhibited this process in dogs [5]. On the other hand, histamine stimulated pepsinogen secretion in isolated mouse [2] or rat [6] stomach and cultured human gastric mucosal cells [7].…”

Section: Resultsmentioning

confidence: 99%

Quantitative analysis of the role of cholinergic, gastrin, and histamine regulatory mechanisms of pepsinogen production in the stomach of narcotized rats

2000

View full text Add to dashboard Cite

show abstract

“…51 Bile salt dewetting occurs at concentrations much lower than those found in the duodenum and jejunum and therefore is not an important factor for the upper GI region. However, bile salt concentrations in the stomach range from 0.01 to 0.1 mM 42,52,53 , and this low concentration regime may be significant in the stomach. Although no dewetting occurs at low pH for TDC, the contact angles at low concentration are considerably high and indicative of poor wetting.…”

Section: Contact Anglementioning

confidence: 97%

Wetting Properties of Bile Salt Solutions and Dissolution Media

Luner

2000

Journal of Pharmaceutical Sciences

View full text Add to dashboard Cite

Use of rotary fluidized-bed technology for development of sustained-release plant extracts pellets: Potential application for feed additive delivery1

Meunier

Cardot

Gauthier

et al. 2006

Journal of Animal Science

View full text Add to dashboard Cite

The aim of this study was to develop sustained release plant extracts as a potential alternative to antibiotic growth promoters for growing pigs. Pellets with a core based on microcrystalline cellulose and 3 active compounds (eugenol, carvacrol, and thymol) were prepared using rotary fluidized-bed technology. Two particle sizes were produced that had a mean size of approximately 250 and 500 mum. Results show the process was able to produce pellets with a spherical and homogenous form when 10% of the active compounds were incorporated into the core. When active compounds were increased to 20%, the pellet became stickier, and the yield decreased from 90 to 65%. Different amounts of coating in the form of an aqueous-based ethylcellulose (EC) dispersion (Surelease) were applied to the core to modify the release of active compounds. The efficacy of the coating was evaluated in vitro using a flow-through cell apparatus. The time to achieve 50 and 90% dissolution increased with the increase in particle size (P < 0.05) and the increase in EC-coating level from 10 to 20% (wt/wt; P < 0.05), indicating the ability of the process to slow release depending on particle size and the amount of polymer applied. Differences in the release of the active compounds were observed in the same formulation of pellets, except for the formulation with small 10%-EC-coated particles, in which the active compounds were rapidly dissolved (more than 85% in 15 min or less). For all other formulations, the dissolution time for eugenol was always faster than for thymol or carvacrol. The close monitoring of plant extract behavior in the gastrointestinal tract could become a key factor in the continued use of phyto-molecules as alternatives to antibiotic growth promoters and in optimizing the balance between cost and efficacy. Different microencapsulation technologies can be used, of which the rotary fluidized bed warrants consideration because of the quality of the products obtained.

show abstract

Bile in the stomach

Cited by 3 publications

References 26 publications

Quantitative analysis of the role of cholinergic, gastrin, and histamine regulatory mechanisms of pepsinogen production in the stomach of narcotized rats

Quantitative analysis of the role of cholinergic, gastrin, and histamine regulatory mechanisms of pepsinogen production in the stomach of narcotized rats

Wetting Properties of Bile Salt Solutions and Dissolution Media

Use of rotary fluidized-bed technology for development of sustained-release plant extracts pellets: Potential application for feed additive delivery1

Contact Info

Product

Resources

About