Behavioral effects of acrylamide in the mouse

Abstract

The behavioral toxicity of acrylamide was characterized in the mouse by comparing standard measures of toxicity such as body weight loss and mortality with measures of hindlimb grip strength, locomotor activity, and appetitive behaviors including episodic milk-licking. In the latter test, the mouse received 15-min access daily to a highly palatable, nonessential food substance (10% sweetened milk) that was not available in the maintenance diet. Two strains of mice, CD-1 and $\text{C57BL}\text{6J}$, were injected ip five times weekly with either saline, 20, 60, or 100 mg/kg of acrylamide. Subchronic, but not acute, administration of 100 mg/kg produced weight loss, a severe neuropathy within 3 days, and 100% mortality within 2 weeks. Mice receiving 60 mg/kg subchronically had only a slight loss of body weight but developed a neuropathy within 3 weeks of dosing at which time there was a 50% mortality. Preceding these signs of toxicity, there was a highly significant increase in episodic milk-licking; this increase was significant in both strains of mice by Day 2 and remained elevated throughout the dosing period. The 20 mg/kg dose of acrylamide decreased hindlimb grip strength after 5 weeks of dosing but did not affect milk-licking or body weight even after 7 weeks of dosing. The new use of this test of appetitive behavior has documented a robust effect of acrylamide which preceded other signs of toxicity. The appearance of the various toxic signs was better predicted by the magnitude of the daily dose than the cumulative dose. This study also demonstrated the feasibility of using the mouse in behavioral toxicology.