BEHAVIORAL AND NEUROCHEMICAL CHANGES ASSOCIATED WITH CHRONIC EXPOSURE TO LOW-LEVEL CONCENTRATION OF PESTICIDE MIXTURES

In order to assess behavioral and neurochemical changes resulting from pesticide exposure, food-restricted male weanling rats were exposed for 90 d to low doses (1 ppb-10, 000 ppb range) of individual pesticides (aldicarb, metribuzin, or methomyl) or mixtures of them. During exposure, rats were trained to run a T-maze and tested for spatial discrimination reversal learning. At sacrifice, three brain regions (cortex, hippo-campus, and neostriatum) were assayed for the neurotransmitters dopamine, acetylcholine, and serotonin. Animals treated with a mixture of two insecticides and one herbicide were found to have slower speeds in maze-running (motor control) and also had altered levels of choline in their neostriatums. Rats treated with one herbicide compound (metribuzin) took longer to learn on two reversals; this group also had a significantly lower acetylcholine/choline ratio in their hippocampus. © 1975 Taylor & Francis Group, LLC.