Age of testing as a factor in the behavioral effects of early lead exposure in rats

The behavioral effects of postnatal administration of lead during weaning were tested in young and adult rats. Rats received either 10 mg/kg IP lead acetate or equimolar sodium acetate daily for the first twenty days of life. Tests of performance on an 8-arm radial maze and a passive avoidance task were begun at 25 days after birth or 90 days after birth. Lead-treated rats did not perform significantly different than control rats on the radial arm maze at either age tested. Young lead-treated rats performed with significantly longer lick latencies than young control rats on the passive avoidance task. Adult lead-treated rats performed with shorter food latencies than adult control rats. A group of young rats was retested on the passive avoidance task at 150 days after birth. Performance on the retest was similar to their early performance. Differences in performance of young and adult lead-treated animals on the passive avoidance task are discussed in terms of an interaction of the effects of lead exposure, maturation, and early experience.