Behavioral effects of postnatal lead acetate exposure in developing laboratory rats

Abstract

At 23 days of age, three groups of male albino Sprague-Dawley rats were exposed to lead at concentrations of 0, 25, or 50 ppm, provided ad lib, in the acetate form, for 35 days in the drinking water. When tested on the problems of the Hebb-Williams closed-field maze learning task, the subjects receiving both 50 ppm lead acetate and 25 ppm lead acetate displayed significantly impaired learning ability when compared to water-fed controls in the total number of error zones entered over the 12 test problems. The time taken to traverse the maze enclosure, however, was significantly reduced only in the group receiving 50 ppm lead acetate. None of the overt manifestations characteristic of lead poisoning were observed. Learning deficits can be produced in the weanling rat at levels of exposure similar to those which cause encephalopathy in the developing neonate.