Participation of vanilloid/capsaicin receptors, calcitonin-gene-related peptide and substance P in gastric protection of omeprazole and omeprazole-like compounds

The effects of omeprazole and different omeprazole-like compounds, associated with anti-ischaemic, antioxidant and poly(adenosine-diphosphate-ribose) polymerase (PARP) inhibitory properties, on the gastric acid secretion (4 h pylorus-ligated) and indomethacin-induced gastric mucosal damage connected with the specific immunohistochemical distribution of TRPV1, CRGP and SP during the effects of these compounds, were studied. The observations were carried out in CFY-strain rats (180–210 g), according to the standard methods and the above-mentioned parameters were studied in these experimental circumstances without and with application of different compounds. We found that: (1) all of the compounds dose-dependently inhibited the gastric acid secretion and mucosal damage; (2) the expression of TRPV1 receptor, CGRP and SP decreased significantly in both pylorusligated and indomethacin-treated animals and (3) the expression of TRPV1 and CGRP was reduced. Meanwhile, no change was obtained in SP expression during the gastric mucosal protection produced by omeprazole and omeprazole-like compounds. The conclusions were that (1) a functional overlap exists between the capsaicin-sensitive afferent and efferent vagal nerve during omeprazole effects; (2) chemical modification of omeprazole molecule offers a new pathway to obtain a new drug for the introduction in the clinical practice.