You are here:
NEUROBEHAVIORAL EVALUATION OF RATS EXPOSED TO CHLORPYRIFOS VIA CHRONIC DIETARY AND REPEATED HIGH-LEVEL SPIKE EXPOSURE.
Citation:
Moser, V C., P. M. Phillips, K. McDaniel, R S. Marshall, D L. Hunter, AND S. Padilla. NEUROBEHAVIORAL EVALUATION OF RATS EXPOSED TO CHLORPYRIFOS VIA CHRONIC DIETARY AND REPEATED HIGH-LEVEL SPIKE EXPOSURE. Presented at Society of Toxicology, Nashville, TN, March 17-21, 2002.
Description:
This study aimed to model long-term subtoxic human exposure to an organophosphorus pesticide, chlorpyrifos (CPF), and to examine the influence of that exposure on the response to intermittent high-dose acute challenges. Adult Long-Evans male rats were maintained at 350g body weight by limited access to CPF-laced food pellets to produce an intake of 0, 1, or 5 mg/kg/day (n=40/feed group). During the year-long exposure, half of the rats in each feed group received bi-monthly challenges (spikes) of CPF, and the other half received vehicle. Rats were periodically tested, using a neurobehavioral screening battery and motor activity, to evaluate the magnitude of the acute response (spike days) as well as recovery and ongoing chronic effects (non-spike days). In non-spiked rats, the lower feed level produced blood but no brain cholinesterase inhibition, whereas the higher feed level produced about 50% brain cholinesterase inhibition. Effects of the spikes differed as a function of dietary level for several endpoints (e.g., tremor, lacrimation), and in general, the high-dose feed groups showed greater effects of the spike doses. In the intervening months, neurobehavioral differences among treatment groups were influenced more by the spike administration than by the level of CPF in the feed. Thus, chronic and intermittent CPF exposure produced long-lasting neurobehavioral changes and altered the response to acute challenges.
This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.