Prenatal Exposure to Cadmium During Organogenesis Impairs Memory in Young Rats

Pregnant rats were treated with 0.3 and 0.6 mg cadmium (CdCl₂)/kg injected subcutaneously on a daily basis from gestational day 7 to day 15 (organogenesis period). One control group was not injected and other received saline. The 45-day-old offspring were tested in a step-down inhibitory avoidance to evaluate short-term and long-term memory and in a radial maze for the study of spatial memory. These studies showed that gestational exposure to 0.6 mg Cd/kg produced in the male offspring a significant impairment in the retention of long-term memory evaluated 24 hours after training in the step-down inhibitory avoidance. The radial maze also demonstrated that the male offspring prenatally exposed to 0.6 mg Cd presented a significant deficit in the retention of spatial memory evaluated 42 days after training. These results demonstrate that the exposure to Cd during organogenesis may affect the retention of some types of memory.