Abstract

Selenium is an essential element with a narrow margin between beneficial and toxic effects. The learning and sensory motor reflexes-changes were studied after the perinatal exposure of mice to acute toxic doses of sodium selenite. Atomic absorption as well as the behavioral observations were employed. Adult pregnant mice was assigned into three groups: the first group was remained as a control group; the second and the third groups were orally administrated sodium selenite at doses of 1 mg/Kg (1 ppm) and 4 mg/kg (4 ppm) of the diet, respectively started from the 7^th day of gestation to the 15^th day of birth. Results revealed that body weight gain came significantly lower in pups born to treated mothers than those of the control pups. The appearance of body hair and opening of eyes of the pups from treated mothers were delayed in a dose-dependent manner. Selenite also inhibited the sensory motor reflexes in all elements in a dose dependent manner. The active avoidance test indicated that selenite exposure was associated with learning impairment. Acetylcholine recorded a significant decrease in treated pups. Significant high concentrations of selenium in the brain, liver and kidney was detected, indicating active transfer of selenium from mothers during pregnancy and lactation periods.

Key words: Perinatal, sodium selenite, atomic absorption, acetylcholine, active avoidance test, sensory motor reflexes, mice.