Toxicology letters
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The present work investigated the effect of preperfusion of ascending concentrations of lead acetate (LA) (10(-9), 10(-7) and 10(-5) M) on digoxin (DGN) cardiotoxicity in isolated frog heart, in order to look for any consequent variations in its lead-induced potentiation. The DGN perfusion time(s) and DGN exposure (micrograms DGN/10 mg heart weight) for, and myocardial DGN level (ng DGN/g wet tissue) at, cardiac arrest were the parameters evaluated so as to assess cardiotoxicity. Both sodium acetate and LA (10(-7) M) preperfusion led to a diminution in cardiac rate at 10 min of DGN perfusion without altering the contractility compared to the DGN alone group. ⋯ On the other hand, in the experimental group that received preperfusion of 10(-9) M LA, the DGN exposure for cardiac arrest was not significantly different from that of the control, whereas in the 10(-7) and 10(-5) M groups, it was significantly lower (P < 0.05). In the experimental group that received preperfusion of 10(-7) M LA, the significant reduction in DGN perfusion time and DGN exposure was well corroborated by a diminution in the myocardial DGN level (4.01 +/- 0.17 ng/g wet tissue in comparison with the control value of 5.72 +/- 0.4 ng/g wet tissue, P < 0.05) at cardiac arrest. Taken together, these data reveal that with the preperfusion of LA in ascending concentrations, there is a relative increase in LA-induced potentiation of DGN cardiotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)