(+/–)3,4-Methylenedioxymethamphetamine (MDMA) Dose-Dependently Impairs Spatial Learning in the Morris Water Maze after Exposure of Rats to Different Five-Day Intervals from Birth to Postnatal Day Twenty
Developmental Neuroscience January 1, 2009 Charles V. Vorhees, Tori L. Schaefer, Matthew R. Skelton et al. 40 citations
Treating rat pups with MDMA during different preweaning periods (postnatal days 1–5, 6–10, 11–15, or 16–20) produced lasting effects. The three highest doses (15, 20, and 25 mg/kg) reduced spontaneous locomotor activity during the first 10 minutes of testing, especially when given on days 1–5 or 6–10. All MDMA-treated groups showed impaired allocentric learning in the Morris water maze during both acquisition and reversal phases; the two highest doses also impaired performance on the small platform phase. No effects were found on anxiety, novel object recognition, or egocentric learning, though a nonsignificant trend appeared. The results indicate that allocentric and egocentric learning have different exposure-duration sensitivities and that the stress hyporesponsive period is not critical for MDMA's effects on allocentric learning.