| Abstract: | 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. |
