[Role of ACE in the gastric cytoprotection. Dopaminergic and peripheral alpha 2 adrenergic mechanisms].

In Wistar rats, four experiments were carried out, studying specific inhibitors for ACE (angiotensin-converting enzyme), such as captopril, enalapril, lisinopril, ramipril and cilazapril, in presence of 20% and 95% ethanol induced gastric lesions. The effect of lisinopril and angiotensin I on the same injury was also studied. Subsequently, drugs with known role in gastric mucosa cytoprotection, such as enprostil, paracetamol, ketotiphen, levamisole, diazepam, bromocriptine, dopamine and clonidine, before and after absolute ethanol gastric injury were also studied. Finally, to examine the potential role of ACE in gastric cytoprotection, pretreatment with enalapril, followed by cytoprotective drugs, was carried out. We conclude that all ACE blockers aggravate the gastric lesion induced by 20% and 95% ethanol and are similar to the findings with angiotensin I. The gastric ACE probably plays an important role in the gastric mucosa defense. On the other hand, gastric ACE, as a physiologic regulator of microcirculation, acts by a double mechanism. a) converting the vasopressor amine, angiotensin I in angiotensin II. b) activating vasoactive peripheric receptors such as DA 2 dopaminergic and alfa 2 adrenoreceptors.