Effect of angiotensin II on striatal dopamine release in the spontaneous hypertensive rat

We have previously demonstrated that angiotensin II stimulates the release of dopamine from the normotensive rat striatum via the AT1 receptor. In this study, the effect of angiotensin II-stimulated striatal dopamine release in the spontaneous hypertensive rat was compared to normotensive controls. In the spontaneous hypertensive rat, angiotensin II stimulated dopamine release to 169 +/- 13% (P < 0.05) in the experimental period, with levels remaining high in the recovery phase, 158 +/- 16% (P < 0.05). This effect was not significantly different from the response in normotensive controls, in which angiotensin II stimulated dopamine release to 149 +/- 18% (P < 0.05) in the experimental period, with the effect also persisting through the recovery period, 244 +/- 62% (P < 0.05). Thus, despite reports of increased activity of the brain angiotensin II and dopamine systems in the spontaneous hypertensive rat, there is no evidence of abnormal regulation of the striatonigral dopamine system.