[Abstract Title]. - Society for Neuroscience

Title: The effects of environmental enrichment with exercise on the antipsychotic-induced
reduction of tyrosine hydroxylase-immunopositive nigrostriatal neurons
Authors: *K. B. REYNOLDS 1 , L. E. S. MACGILLIVRAY 1 , P. I. ROSEBUSH 2 , M. F.
MAZUREK 2 ;
1 Hlth. Sci., 2 Psychiatry and Behavioural Neurosciences, McMaster Univ., Hamilton, ON, Canada
Abstract: Background and Objectives: Patients treated with antipsychotic drugs (APDs) are
prone to developing parkinsonism. We have previously reported a long-term downregulation of
nigrostriatal dopaminergic neurons following treatment with APDs similar to the changes
observed in animal models of idiopathic Parkinson‟s Disease (PD). Environmental enrichment
(EE) prior to or following toxin exposure, has been shown to attenuate both the behavioural
consequences and the neurochemical changes seen in animal models of PD. We postulated that
EE with exercise may attenuate the toxic effects associated with APD treatment.
Methods: At 3 weeks of age male Sprague-Dawley rats (n=41) were placed into either a
standard or an enriched environment. In the standard environment, animals were housed
individually with no enrichment objects. In the enriched environment, animals were housed ten
animals per cage with two running wheels as well as other enrichment items that were changed
and rearranged regularly. After approximately 9 weeks, the rats were assigned to one of four
different treatment groups. One group of rats in enriched housing (n=10) and one group in
standard housing (n=11) received oral haloperidol treatment (HAL; 2 mg/kg/day) for 7 days
while the other two groups (n=10; n=10) received saline. Sections of the substantia nigra (SN)
were processed for tyrosine hydroxylase (TH) immunoreactivity, and cells were counted
manually. Results were analyzed by pre-planned t-tests. Significance was set at p