Further evidences on gastric cytoprotection exerted by pirenzepine

Pirenzepine (P) exerts cytoprotective action through a mechanism so far poorly understood. The aim of the present work was to evaluate the protective effect of P and by comparison PGE2, in different cytoprotective models: NaOH 0.2 N; antral ulcer induced by indomethacin; and in an "in vivo" model using ethanol (50% 1ml/rat p.o.) as mucosal barrier damaging agent. In this last group of experiments gastric mucosal potential difference (DP), Na+ concentrations and pH were measured. These parameters provided a clear measure of the mucosal barrier recovery from damaging agents. P., like PGs, significantly protect mucosa against NaOH 0.2 N induced ulcers with an ED50 = 21.94 mg/kg os, a similar activity was found for the antral ulcers induced by indomethacin (ED50 22.06 mg/kg os). Moreover P. significantly antagonized the PD reduction induced by ethanol in rat. PGE2 was strikingly active in this model. P. and PGE2 significantly decreased also Na+ ion concentration altered by ethanol. Although this paper shows a positive effect of P on the gastric mucosal barrier, further studies are necessary to clarify the mechanism of gastric cytoprotection of P.