Effects of exposure to a pyrethroid insecticide during lactation on the behavior of infant and adult rats

RESUMO

Cyhalothrin, a pyrethroid insecticide, was administered to female Wistar rats as a 0.02% solution plus 0.04% sucrose (w/v) in drinking water from whelping to pup weaning after 21 days of lactation. The pesticide did not change the maternal behavior of the dams as measured by the scoring system of Sderstein and Eneroth. The body weight of pups exposed to the pesticide and at age 90 days was not different from that of controls, and the motor activity of the pups measured in a simple photocell activity cage was not affected by pesticide treatment. Furthermore, no overt sings of neural toxicity were observed in the offspring. However, the treatment disrupted rat behavior in adulthood when assessed by using an inhibitory avoidance learning task. Thus, inhibitory avoidance tests carried out on rats at 90 days of age were capable of demonstrating neural toxicity of Cyhalothrin (0.02%) present only in the drinking water of dams during 21 days of lactation