Summary of findings.

<p>Compared with control (A), in 6OHDA-lesioned rats, there were relatively more VGLUT-1 labeled terminals making synapses upon the shafts of dendrites (red circle; B). We hypothesise that this is due to fewer spines being available. There was no change in density of glutamate labeling. With STN lesions, there was decreased glutamate labeling in VGLUT1-labeled terminals, indicating increased release, indicated here by increased line thickness (C). With STN stimulation, there was decreased glutamate labeling, suggesting increased release in both types of terminals, and an increase in the proportion of VGLUT1-labeled terminals upon spines (red circle; D). We did not count spines, but postulate that there were more spines available for synapses due to plasticity. The relative numbers of VGLUT1-labeled and –unlabeled terminals and their locations are not accurate.