TRACE ELEMENTS AND ELECTROLYTES, cilt.20, sa.3, ss.154-159, 2003 (SCI-Expanded)
In this study, we investigated the effects of chronic manganese chloride (MnCl2) application at high dosage on the mechanical responses evoked by acetylcholine (2.7 x 10(-7) M) on isolated rat ileum in standard and calcium-free tyrode perfusion solutions with diltiazem (5.5 x 10(-7) M) and non-diltiazem mediums. In the experimental group (n = 10), MnCl2 (50 mg/kg/day) was injected for 50 days intraperitoneally. Acetylcholine-induced contraction amplitude increased significantly with respect to that of the control in standard tyrode perfusion medium. When ileal segments were pre-incubated with diltiazem, the amplitude of acetylcholine-induced contractions decreased in experimental and control groups with respect to those of the standard mediums. In calcium-free medium, pretreatment with diltiazem did not cause any change in acetylcholine-induced contractions. Our data suggested that manganese (Mn2+) might have penetrated through cell membrane and accumulated in the cell when. manganese was applied chronically and overdose. Increase in plasma manganese level might have induced the increase in manganese influx whereas calcium influx might have been induced by manganese itself The increase in contraction amplitude maybe attributed to this phenomenon.