The aim of the present study was to investigate the impact of
prenatal methamphetamine (MA) exposure and application of the
same drug in adulthood on cognitive functions of adult male rats
tested in Morris water maze (MWM). Adult male rats prenatally
exposed to MA (5 mg/kg), saline or no injection were examined.
Half of the animals were injected daily with MA (1 mg/kg) after
finishing the testing. Three types of tests were used: (1) “Place
navigation test” (Learning), (2) “Probe test” and (3) “Retention
memory test” (Memory). Our results showed that prenatal MA
exposure did not affect the test of learning and the Probe test. In
the test of memory prenatally MA-exposed rats showed smaller
search errors and used spatial strategies more than both control
groups. Further, MA application in adulthood prolonged
trajectories, increased the incidence of random search and
decreased the incidence of direct swim in the Place navigation
test. In addition, MA administration in adulthood increased the
speed of swimming regardless of prenatal exposure. The present
study thus demonstrates that 1) Prenatal MA exposure does not
affect learning in the MWM, 2) Prenatal MA exposure improves
performance in the Retention memory test in the MWM, and
3) MA application in adulthood impairs learning in the Morris
water maze.