Effects of a pyrethroid type II pesticide on conditioned behaviors of rats.

Our present work investigated the effect of fenvalerate, a pyrethroid type II pesticide, on conditioned behaviors of rats. Pre-training administration of the pesticide did not modify passive avoidance but decreased active avoidance responses and operant conditioned responses; pre-training or pre-test administration of fenvalerate induced a facilitatory effect on passive avoidance task; pre-training and/or pre-test treatments reduced active avoidance responses of rats which received the pesticide before test; and post-training treatments were not capable of modifying both active and passive avoidance responses. Increased emotionality produced by the action of fenvalerate on the sympatho-adrenal system could be responsible for the differences observed between active and passive avoidance responses.