Measurement of Gastric Acid Secretion in the Anaesthetized Rat

Maristella Adami1, Gabriella Coruzzi1

1 University of Parma, Parma, Italy
Publication Name:  Current Protocols in Toxicology
Unit Number:  Unit 21.5
DOI:  10.1002/0471140856.tx2105s45
Online Posting Date:  August, 2010
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Abstract

The protocols described in this unit are designed to assess the effects of substances on gastric acid secretion by the rat stomach, with the animal under general anesthesia. Both stimulatory and inhibitory effects of compounds can be evaluated and specific mechanisms of action can also be investigated. Acid secretion is induced by substances that directly activate parietal cell receptors (histamine and bethanechol), by indirect stimuli, like 2‐deoxy‐D‐glucose, by electrical stimulation of vagal nerves, or by the peptide pentagastrin. Reference antisecretory drugs are represented by histamine H2 receptor antagonists and proton pump inhibitors. This model allows the evaluation of complete dose‐response curves together with a time‐course of the secretory/antisecretory effects. Indirect effects involving activation or inhibition of vagal pathways are evaluated in intact animals by means of electrical vagal stimulation or in vagotomized animals. Curr. Protoc. Toxicol. 45:21.5.1‐21.5.12. © 2010 by John Wiley & Sons, Inc.

Keywords: stomach; gastric acid secretion; anaesthetized rat; histamine; pentagastrin; bethanechol; 2‐deoxy‐D‐glucose; vagal pathways

     
 
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Table of Contents

  • Introduction
  • Basic Protocol 1: Acid Collection from the Stomach of the Anaesthetized Rat
  • Support Protocol 1: Isolation of Vagal Nerves
  • Alternate Protocol 1: Measuring Gastric Secretion in Vagotomized Animals
  • Reagents and Solutions
  • Commentary
  • Literature Cited
  • Figures
  • Tables
     
 
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Materials

Basic Protocol 1: Acid Collection from the Stomach of the Anaesthetized Rat

  Materials
  • Male Wistar rats (∼200 to 250 g)
  • Rat food
  • 25% (w/v) urethane (see recipe)
  • Saline: 0.9% (w/v) NaCl (see recipe), 37°C
  • 10 mM NaOH ( appendix 2A)
  • Test compounds in appropriate vehicle: histamine, bethanechol, pentagastrin, or 2‐deoxy‐D‐glucose (see reciperecipes)
  • Rat cages and access‐restricted temperature/light‐controlled room
  • Animal balance accurate to 1 g (e.g., Sartorius)
  • Surgical instruments:
    • Sharp and blunt scissors
    • Small straight anatomical forceps
    • Large straight anatomical forceps
    • Cotton wool
    • Esophageal cannula (≥10‐cm long polyethylene tube with beveled end; 0.2‐cm diameter)
  • Glass pipets
  • 5‐ml plastic syringes
  • Duodenal cannula (≥6‐cm long polyethylene tube; 0.2‐cm diameter)
  • Rat surgical board
  • Adhesive tape
  • Rectal temperature probe
  • Thermostat‐controlled heat lamp
  • Perfusion setup including:
    • 40° to 42°C water bath
    • Peristaltic pumps (two pumps capable of delivering 0.1 to 1 ml/min)
    • 500‐ml flasks
    • Perfusion tubes (e.g., accurate tubing: flow rate 0.10 ml/min and 1.40 ml/min)
    • Thermometer
  • 30‐ml plastic beakers
  • Automatic titration system (Radiometer, Copenhagen)
  • pH meter (pH 4 and pH 7 buffers for pH meter calibration)
  • Titration assembly with electrodes

Support Protocol 1: Isolation of Vagal Nerves

  Materials
  • Blunt‐end forceps
  • Cotton thread
  • Electrodes (two handmade platinum curved electrodes; 0.8‐cm long and 0.2‐mm diameter)
  • Electronic stimulator (Grass model S88K stimulator)
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Figures

Videos

Literature Cited

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   Bertaccini, G., Endean, R., Erspamer, V., and Impicciatore, M. 1968. The actions of caerulein on gastric secretion of the dog and the rat. Br. J. Pharmacol. 34:311‐329.
   Black, J.W., Duncan, W.A., Durant, C.J., Ganellin, C.R., and Parsons, E.M. 1972. Definition and antagonism of histamine H2‐receptors. Nature 236:385‐390.
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   Sababi, M. and Nylander, O. 1996. Comparative study of the effects of nitric oxide synthase and cyclo‐oxygenase inhibition on duodenal functions in rats anaesthetized with inactin, urethane or α‐chloralose. Acta Physiol. Scand. 1158:45‐52.
   Schubert, M.L. 2009. Gastric exocrine and endocrine secretion. Curr. Opin. Gastroenterol. 25:529‐536.
   Shea‐Donohue, T. 1996. Methods for assessing gastric secretion. In Methods in Gastrointestinal Pharmacology (T.S. Gaginella, ed.) pp. 1‐36. CRC Press, Boca Raton, Florida.
   Soll, A.H. and Berglindh, T. 1994. Receptors that regulate gastric acid secretory function. In Physiology of the Gastrointestinal Tract, Volume 2 (R.L. Johnson, ed.) pp. 1139‐1169. Raven Press, New York.
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   Takeuchi, K., Ohuchi, T., Miyake, H., Niki, S., and Okabe, S. 1993. Effects of nitric oxide synthase inhibitors on duodenal alkaline secretion in anaesthetized rats. Eur. J. Pharmacol. 231:135‐138.
   Vatier, J., Olivier, A., and Mignon, M. 1988. Modern aspects of antisecretory drug evaluation: Animal models. In Control of Acid Secretion (M. Mignon and J.P. Galmiche, eds.) pp. 73‐89. John Libbey Eurotext, Paris.
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   Watanabe, H., Mochizuki, T., and Maeyama, K. 1996. Transient increase of blood histamine level induced by pentagastrin. Continuous monitoring by in vivo microdialysis. Scand. J. Gastroenterol. 31:1144‐1150.
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Key Reference
   Schubert, 2009. See above.
  An up‐to‐date and comprehensive review describing the regulation of acid secretion.
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