Alterations in Motor Activity Induced by High Dose Oral Administration of Dextromethorphan Throughout two Consecutive Generations in Mice

To achieve a better understanding of the effects on behavioral safety caused by possible neuroprotective doses (50 mg/kg, p.o.) of dextromethorphan HBr (DM), several motor activity measures were monitored in two generations of mice through a long-term period of ten months. Adult male mice (G1), in the presence of DM, developed behavioral tolerance after an initial suppression period. Prenatally exposed, second generation (G2) mice formed two groups, prenatal exposure alone (G2C) and prenatally exposed with additional postnatal exposure (G2T). In the presence of DM, group G2T was characterized by significant behavioral impairment; while G2C exhibited behavioral activation. These results suggest that more attention should be given to the prenatal effects of DM on a developing organism.