Effects of Prenatal Exposure to Nicotine on Working Memory, Activity, Sensory Gating, and Dopamine Receptor Binding in Adolescent and Adult Male and Female Rats
UNIFORMED SERVICES UNIV OF THE HEALTH SCIENCES BETHESDA MD BETHESDA United States
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Exposure to nicotine in utero results in a wide array of physical, behavioral, and cognitive effects on the offspring. Some of these effects are evident at birth and some do not appear until later in life. In the present experiment, pregnant female Sprague-Dawley rats were administered nicotine 6 or 12 mgkgday or saline via osmotic minipumps chronically throughout pregnancy and the offspring were examined during adolescence and adulthood for changes in body weight, radial-arm and water maze performance, passive avoidance performance, acoustic startle reactivity, pre-pulse inhibition, locomotor activity, and dopamine 01 receptor binding in the medial prefrontal cortex. Effects of prenatal nicotine exposure depended on nicotine dosage, the sex and age of the subject. Specifically, females and males that had been exposed to the highest dose of nicotine in utero weighed less than the other offspring throughout the experiment. These females also made more mistakes on the radial-arm maze and were less active during adolescent testing than the other females. When tested in adulthood, the females that had been exposed to 6 mgkgday nicotine showed enhanced pre-pulse inhibition an index of sensory gating. Adolescent males that had been exposed to 6 mgkgday nicotine took longer to complete the water maze task, but were more active than the other adolescent males. When tested as adults, males that had been exposed to either dosage of nicotine performed more poorly than non-drug-exposed males on the radial-arm maze they made fewer correct choices before an error was made and took longer to complete the task and showed impaired pre-pulse inhibition. However, these same males showed enhanced passive avoidance learning. Dopamine D1 receptors of either sex were not significantly affected by prenatal exposure to nicotine.