The results of immunohistochemical staining were submitted for evaluation in an Olympus Bx50 microscope. Gastrin-, SY- and ANP-IR cells were searched for and their topography was observed. Immunopositive cells were counted in five (5) randomly selected microscopic fields, each field of 0.785 mm2, in magnification of 200 x (20 x the lens and 10 x the eyepiece) in the longitudinal sections of the stomach. Three (3) sections of each rat were analyzed. The numbers of positively stained cells were presented as mean values per 1 mm2 of the analyzed stomach section area. The corresponding mean values were computed automatically; significant differences were determined by Student’s t test; p < 0.05 was taken as the level of significance.