Evaluation of the angiotensinogen locus in human essential hypertension: a European study

Adult male Wistar rats were implanted bilateraly with bipolar electrodes in substantia nigra-ventral tegmental area (SN-VTA) to experience intracranial self-stimulation (ICSS) for 15 min per day over a period of 10 days. These rats were then assessed for the acquisition and performance of the operant and the spatial learning tasks. ICSS experienced rats showed rapid acquisition of both the operant and the spatial learning tasks. Both the lever press performance for 7 sessions in the operant learning task and mean number of alternations per session in the spatial learning task were significantly higher (p < .001) in ICSS experienced rats compared with controls. The results suggest that prior ICSS experience facilitates the acquisition and performance in both the operant and the spatial learning tasks, which may be due to the structural and neurochemical alterations in the hippocampus induced by ICSS experience.