Master of Arts (MA)
Faculty of Science
Five experiments examined the effects of repeated exposure to stimulants, largely apomorphine (APO), on wheel running in male Sprague-Dawley rats. In these experiments, minor changes in procedure resulted in profound differences in the effects of APO on wheel running. Experiment 1 I compared changes in wheel running after repeated injections of 3.0 mg/kg amphetamine (AMP), 5.0 mg/kg of APO or vehicle (VEH). AMP resulted in a suppression in wheel running which become more pronounced over trials, while running in APO animals remained similar to the VEH group. Testing provided support for a conditioned suppression of wheel running rats previously treated with AMP relative to those treated with VEH. Experiments 2 to 4 examined the effects of repeated injections of a wide range of APO doses on wheel running in two different environments, a wheel rack and separate wheel cages. Results showed significant quadratic trends in Experiments 2 and 3, suggestive that low APO doses suppress running and higher doses elevate running. However, running in rats repeatedly injected with 1.0 mg/kg APO was either suppressed or elevated, depending on the environment in which they were tested. Experiment 4 concurrently examined the effects of 1.0 mg/kg APO in both environments and found that running on the rack was significantly higher than in the separate cages for the APO animals, but did not differ from VEH treated controls. The effect of noise on APO-induced running in the SEP cages was examined in Experiment 5 but had no effect on the wheel running.
Vilaysinh, Vanhthong, "Sensitization to indirect and direct dopamine agonists: Behavioural differences in wheel running" (2001). Theses and Dissertations (Comprehensive). 719.