Assessment of the effects of acrylamide, methylmercury, and 2,5‐hexanedione on motor functions in mice

Neurotoxic effects of acrylamide, methylmercury, and 2,5-hexanedione were studied in forty female BALB/c mice. Motor functions were quantified by measuring landing foot-spread and rotarod performance. Baseline data were collected before dosing started. Mice were placed, twice weekly, on an accelerating rotarod, and their retention time was recorded. Decreased retention time and increased hindlimb splay were observed in mice after 12 d of exposure to acrylamide. Recovery followed treatment cessation. Increased hindlimb splay preceded an obvious decline of rotarod performance in the group receiving the 10 ppM of methylmercury solution. Mice receiving the 20 and 40 ppM of methylmercury solutions did not display any change in these tests before overt signs of toxicity. 2,5-Hexanedione produced a small decline in performance to a constant level after 85 d of exposure. After dosing termination, performance returned to baseline values. Control groups showed no change in performance on either the rotarod or the landing foot-spread test. Our data show that the rotarod and hindlimb splay tests in mice are about equal in sensitivity to the effects of the neurotoxic chemicals tested.