Psychostimulants, including methamphetamine (MA), haveneurotoxic effect,
especially, if they are targeting CNS during its critical periods of development. The present study was aimed to examine cognitive changes after prenatal and neonatal MAtreatment in combination with chronic MA
exposure in adulthoodof male rats. Eight groups of male rats were tested in adulthood:males whose mothers were exposed to MA (5 mg/kg) or saline(SA, 1 ml/kg) during the first half of gestation period (GD 1-11),the second half of gestation period (GD 12-22) and neonatalperiod (PD 1-11). In addition, we compared indirect neonatalapplication via the breast milk
with the group of rat pups that received MA or SA directly by injection
(PD 1-11). Males weretested in adulthood for cognitive changes in the
Morris WaterMaze (MWM). MWM experiment lasted for 12 days: Learning(Day 1-6), Probe test (Day 8) and Retrieval Memory test
(Day 12). Each day of the MWM animals were injected with MA(1 mg/kg)
or SA (1 ml/kg). Prenatal MA exposure did not inducechanges in learning abilities of male rats, but neonatal exposureto MA leads to an increase search errorsand latencies to find thehidden platform. Prenatal and also
neonatal MA exposureimpaired cognitive ability to remember the position of the platform in Retrieval Memory test in adulthood. Animals exposed to the
prenatal treatment within the second half of gestation(ED 12-22) swam longer, slower and spent more time to find the hidden platform in Retrieval Memory test than animals exposedthroughout other periods. The present
study demonstrated thatstage of development is crucial for determination
the cognitivedeficits induced by prenatal or neonatal MA exposure.
It is known that psychostimulants including methamphetamine (MA) have neurotoxic effect, especially, if they are targeting CNS during its critical periods of development. The present study was aimed on evaluation of cognitive changes following scheduled prenatal MA exposure in combination with long-term exposure in adulthood of male rats. Two periods of gestation were targeted: 1st half - the embryonic day (ED) 1-11 and 2nd half - ED 12-22. Rat mothers received subcutaneously a daily injection of MA (5 mg/kg) or saline (SAL, 1 ml/kg) throughout scheduled periods. Male offspring were tested for cognitive changes in the Morris Water Maze (MWM) in adulthood. Each day of the experiment animals received an injection of MA (1 mg/kg) or SAL (1 ml/kg) during 12 days. Our results demonstrated that in the group of animals exposed to the drug during ED 1-11, neither prenatal MA exposure, nor adult MA treatment changed the performance in the MWM test. Only the velocity was increased in group with long-term MA treatment (SAL/MA and MA/MA). In the group of animals exposed to the drug during ED 12-22, rats exposed to MA prenatally and also in adulthood (MA/MA) swam faster but learned the position of the platform slower in the Place Navigation Test than animals exposed to SAL in adulthood (MA/SAL). In the Probe Test, MA/SAL had decreased velocity and swam shorter distance than MA/MA or SAL/SAL rats suggesting increased floating of these animals. In the Memory Retention Test, SAL/MA rats swam shorter distance than SAL/SAL or MA/MA animals suggesting changes in used strategies in memory recall. As conclusion, our results suggest differences in the effect of combination of prenatal and adult exposure to MA. These effects further depend on the stage of CNS development and schedule of MA exposure affecting intrauterine development in male rats., I. Hrebíčková, M. Malinová-Ševčíková, E. Macúchová, K. Nohejlová, R. Šlamberová., and Obsahuje bibliografii