Effects of intrastriatal injections of the cholinergic neurotoxin AF64A on spontaneous nocturnal locomotor behavior in the rat.

Rats with bilateral striatal cholinergic lesions induced by the neurotoxin AF64A were found to have increased spontaneous nocturnal locomotor activity as measured in terms of the amount of time spent moving, the total distance traveled and the number of episodes and time of stereotypic behaviors. No significant differences between control and AF64A injected rats were found in the actual velocities between the two groups indicating that the rats were simply spending more time moving rather than moving with greater speed. Striatal activity of choline acetyltransferase (CAT) was significantly decreased in AF64A treated rats compared to controls, whereas the activities of glutamate decarboxylase (GAD) were not. Furthermore, there were no significant differences between groups in enzymatic activities of CAT and GAD in either the cortex or the hippocampus, indicating that the lesion was restricted to the striatum. The hyperactivity found in these rats after intrastriatal injection of AF64A supports a role for the striatal cholinergic system in locomotor behavior.