MO082THE EFFECTS OF DIFFERENT MICROMOLAR CONCENTRATIONS OF CADMIUM IONS ON THE PERITUBULAR MEMBRANE POTENTIAL OF PROXIMAL TUBULAR CELLS IN PERFUSED FROG KIDNEYS

Abstract Background and Aims Cadmium (Cd2+) is toxic metal environmental pollutant. Accumulation of cadmium in the kidney results initially proximal tubule dysfunction. Although Cd2+ toxicity well documented, all mechanisms that are involved early stages nephrotoxicity, especially considering low micromolar concentrations ions still unknown. The Aim this study was to investigate effects acute exposure different peritubular (0.25, 0.50, 1.0, 2.0, 3.0, 5.0 μmol/L) on cell membrane potential tubular cells frog kidney. Method experiments were performed isolated, doubly perfused kidneys Rana esculenta both sexes. Aortic portal vein cannulated order perfusate luminal membraine. In controled conditions, Ringer solution simultaneously used membraines. chloride (different concentrations: 0.25, added separately, by switching from control with addition ions. Peritubular potentials (PD) measured conventional 3 mol/L KCl microelectrodes. Results application led a rapid, sustained, reversible hyperpolarization membrane: 0.25 µmol/L, −3.3±0.4 mV (n=8, p<0.001); 0.50 −3.0±0.5 (n=11, 1.0 −2.9±0.6 p<0.01); 2.0 −4.2±0.4 (n=13, 3.0 −3.4±0.3 (n=14, −3.0±0.4 (n=10, p<0.001). After perfusion Ringer, membraine returned average values maintained before (p>0.05). Comparing effect concentrations, there no difference (p>0.05).Each served as its own control. Conclusion Different provoked rapid sustained did not show concentration-dependent response.