Effect of melatonin on neurobehavioral dysfunctions induced by intrauterine hypoxia in rats.

Intrauterine hypoxia associated with oxidative stress represents an important risk factor for development of neurobehavioral dysfunctions. In the present study, we investigated the potential protective effect of melatonin (MEL) on neurobehavioral dysfunctions induced by chronic intrauterine hypoxia in rats by the anticonvulsant drug phenytoin (PHT), which is known by its teratogenic potential. Pregnant female rats (Wistar/DV) were orally treated by PHT (150 mg/kg) from day 7 to 18 of gestation. MEL was dissolved in drinking water (40 microg/ml) and administered from day 0 to 19 of gestation. Neurobehavioral development of offspring was evaluated from birth up to day 90 of postnatal life. The results of the study confirmed the high behavior-teratogenic potential of PHT. Prenatal administration of PHT resulted in delayed neuromotor and reflex development, decreased exploration in the open field, abnormal "circling" and impaired performaces in water maze. Co-administration of MEL failed to have any effect on neurobehavioral dysfunctions induced by PHT treatment. Even administration of MEL alone caused developmental alterations in offspring manifested by accelerated testes descent and delayed onset of negative geotaxia and startle reflex. The results suggest to pay increased attention to MEL concerning its exogenous use during pregnancy.