The effects of methamphetamine exposure during preadolescence on male and female rats in the water maze

Abstract

Exposure to methamphetamine early in life can have lasting effects on cognitive processes. The maturation of neurotransmitter systems targeted by methamphetamine differs by gender during childhood and preadolescence, which could lead to differential long-term effects of early drug exposure. Therefore, the current study assessed whether preadolescent exposure to methamphetamine has gender specific long-term effects on adult spatial memory in rodents. Male and female rats were given 1 daily injection of 0 or 2 mg/kg methamphetamine or not handled from PD21–35 and then tested as adults (PD95) in the Morris water maze. In general, male rats performed better than female rats in the water maze task regardless of treatment group. Female rats exposed to methamphetamine from PD21–35 had shorter latencies and took more direct paths to the hidden platform compared to control females during the 4 days of acquisition training and when the hidden platform was moved each day on matching to place trials. Male rats exposed to methamphetamine swam a shorter distance to the hidden platform on the first day of acquisition training, similar to the methamphetamine exposed females. However, the methamphetamine exposed males performed more poorly compared to control males in the matching to place trials. Overall, the current study found that methamphetamine exposure during preadolescence has long-term effects on spatial memory in a gender specific manner. These findings may contribute to our general understanding of the long-term effects of psychostimulant exposure at early developmental stages.