The purpose of this project is investigation of basic mechanisms associated with neurological disease using animal models that have been produced by exposure to synthetic or naturally occurring neurotoxins. The interactions of various toxins with neurotransmitters and hormones in the CNS have provided the focus for combined behavioral and neurochemical studies emphasizing basic mechanisms of action of proposed neurotoxins. Two major interests of this project are: 1) to define populations of individuals that may be at increased risk to neurological disease resulting from exposure to neurotoxins and 2) to use naturally occurring variability in central nervous system function, anatomy and/or neurochemistry, to elucidate mechanisms of actions of neurotoxins. The primary emphases this year have been: 1) the interaction of artificial food colors with neuronal membranes and neurotransmission; 2) the investigation of genetic and age variation in brain Na,K-ATPase (an enzyme previously demonstrated to be inhibited by artificial food color); and 3) neuronal interactions between neuropeptides and dopamine in the basal ganglia.