Z Gastroenterol 2006; 44 - A80
DOI: 10.1055/s-2006-943446

Drug actions on the afferent and efferent fibres of the vagal nerve in the gastric mucosal protection: a molecular pharmacological approach

G Mózsik 1, O Abdel-Salam 2, A Dömötör 1
  • 11st Department of Medicine, Medical and Health Centre
  • 2National Research Centre, Cairo, Egypt

Background: The gastric mucosal protection is associated with the effects of drugs affecting on the afferent and/or efferent fibers of the vagal nerve.

Aims: 1. To identify the dose-response curves of drugs affecting on the afferent (capsaicin, RTX) and efferent nerves (atropine, pirenzepine, cimetidin, ranitidine, famotidine, omeprazole, esomeprazole) on gastric acid secretion, chemicals-induced gastric mucosal damage in rats and in healthy human subjects; 2. To identify and to compare the ED50 values of these compounds.

Materials and Methods: 1. The observations were carried out in rats and in healthy human subjects. NSAIDs were used to produce gastric mucosal damage.

Results: 1. ED50 values of the compounds were found: 3,27 nmol/kg capsaicin for inhibition of gastric acid secretion in 2h pylorus-ligated rats and 0,954 nmol/kg RTX in 1h pylorus-ligated plus bethanecol (75µg/kg sc.), histamine (2,7 and 13,6µmol/kg sc.) and 65,1 nmol/kg pentagastrin sc. stimulated gastric acid secretion; 1,98 nmol/kg capsaicin and 0,95 nmol/kg RTX for inhibition the gastric mucosal damage in 20mg/kg indomethacin plus 4h pylorus-ligated rats, 20mg/kg indomethacin in 0,15 N HCl for 4h pylorus-ligated rats. 2. The ED50 value of capsaicin is 0,327–2,616µmol/kg for inhibition of gastric acid output and indomethacin-induced gastric mucosal damage in healthy human subjects; 3. The ED50 values for atropine 3,45µmol/kg, 0,1178 mmol/kg for Pirenzepine, 1,58–3,96 mmol for cimetidine, 0,478–0,954 mmol/kg for ranitidine, 0,119–0,237 mmol/kg for famotidine and 57,9–115,8µmol/kg for omeprazole and esomeprazole.

Conclusion: 1. The molecular concentrations (ED50 values) of drugs acting on the afferent nerve are 2–3 times less than those on the efferent nerves; 2. The stimulation of capsaicin-sensitive afferent nerves by capsaicin represents the first line in the regulation of gastric secretion and development of gastric mucosal prevention in animals and humans.