The gastric secretion mechanism and the factors related to the formation of the peptic ulcer are important aspects for the medicine development new that can act as antagonistic in these processes. The used medicines as citoprotetores tend to increase the resistance of the gastric mucosa and to diminish the harmful agents (CAVALINI, 2005). 3.3. Mechanisms of gastric protection Physiological, the aggressive and protective agents of the gastric mucosa are in balance. The concentration of H+ in the lumen of the stomach is raised, however, mechanisms exist that hinder its return for the gastric cells. Amongst the protective mechanisms it is to the stimulation of the mucous cells, for the Ach, for protective release of muco (MILK, 2004).

The electric resistance of the membrane of the epithelial cells, the high cellular junctions and the negative electric potential of the way hinder the passive ticket them ons H+ through the cellular membranes. The defense of the gastric mucosa is based on three main mechanisms: humorais (release of E2 Prostaglandin) and nitric oxide (IN), neural (sensorial neurons) and functionaries (secretion of muco, motilidade and microcirculation) (RODRIGUES, 2008). The mucous cells liberate muco protective, forming viscous, transparent, adherent and elastic a system (95% water and 5% glycoproteins). Muco recovers the fabric gastric, acting as a sweeper of free radicals, aid in cellular regeneration and the cicatrizao of ulcerativas injuries (RODRIGUES, 2008). The barrier muco-bicarbonate-fosfolipdios hinders the installation of microorganisms, making physical protection against foods and acts as a powerful lubricant (ROZZA, 2009).

In the interior of the cells of the mucosa, the oxidation-reduction system functions (redox), that it acts as a citoprotetor system. The free radicals are formed physiological and in inflammatory processes, then, the system redox if it becomes essential for the reduction of less reactive free radicals ons, increasing the cellular protection (MAYER, 2007).