The goal of this study to evaluate the possible effects of three different doses of pantoprazole exposure on rat pyloric sphincter contractile tone and contraction frequency in an in vitro experimental study. Following a 60 min equilibration period for stabilization, the contractile response to carbachol was obtained by application of a single dose of carbachol. After the contractions plateaued, pantoprazole concentration-response curves for the experimental group (n= 10) were obtained in a cumulative manner for pantoprazole doses of 5 x 10(-6) mol/L, 5 x 10(-6) mol/L and 1.5 x 10(-4) mol/L, with each dose being held for 15 min. In the control group (n= 10), distilled water was added to the organ bath. Mean percentage of changes in contractile tone and contraction frequency were calculated for each 15 min periods. The contractile tone and contraction frequency decreased in all periods in both groups. Neither contraction tone nor contraction frequency mean percentage of change differed among the periods in the control group. In the experimental group, significant inter-period differences were observed for mean change in contraction tone (period 1 vs. 2, p = 0.013) but not for mean change in contraction frequency (all p > 0.05). It was thought that pantoprazole may relax the pyloric ring by decreasing contractile tone in a dose-dependent manner.