The range finding study for dicrotophos suggested the same time
course as seen with monocrotophos, and therefore the same test
times, and molar-equivalent doses, were used. Brain ChE data (Fig. 4)
showed a significant dose-by-age interaction, and suggests that both
the PND11 and 17 pups were more sensitive compared to adults. On
the other hand, there was not a significant factor of age or an
interaction of dose and age for the RBC ChE data. These findings are
reinforced by the significant differences in ED50 estimates for brain
but not RBC ChE (Table 1). The lowest dose of 0.107 mg/kg
significantly decreased brain ChE in PND11 pups, and for all ages
and both tissues, doses of 0.213 mg/kg and above were significantly
different from control. PND11 pups were not tested in the motor
activity chambers, thus age differences could only be examined
between the PND17 and adult rats (Fig. 5). For motor activity counts