Behavioral effects of ivermectin in mice

Background and Purpose: Ivermectin is a common anthelmintic drug, widely us ed in laboratory rodents for treatment of pinworm and mite infestations. We evaluated the action of ivermectin on sensitive behavioral tasks in mice d uring treatment for mites within a barrier facility. Methods: A total of 21 (5 males, 16 females) mice (129/SvEv) were used for measuring body weight, open field locomotor activity, and rotarod motor coo rdination. For acoustic startle and prepulse inhibition, 20 C57BL/6J and 29 AKR/J mice were studied. For the Morris water task, the same 20 C57BL/6J m ice were studied. Ivermectin (0.08% sheep drench) was administered in the d rinking water of the home cage for 8 weeks. Control groups received normal tap water in identical bottles. Results: Ivermectin did not affect general health, body weight, motor coord ination, swimming behavior, or spatial learning in several inbred strains o f mice. However, it induced a small but significant effect on some sensitiv e behaviors. Conclusions: A cautious approach to initiating ivermectin treatment in mice should be used for sensitive behavioral experiments.