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Keywords:

  • angiotensin II;
  • blood pressure;
  • brain;
  • hypertension;
  • losartan;
  • statins;
  • stress;
  • vasopressin

Summary

  1. Brain angiotensin (Ang) II and vasopressin play important roles in the neurogenic regulation of the circulatory system, such as in cardiovascular responses to stress. Recently, it has become evident that the positive effects of statins are not limited to their lipid-lowering actions; for example, it has been found that statins interact with angiotensin peptides.
  2. In the present study we tested the hypothesis that simvastatin affects haemodynamic responses to air-jet stress and intracerebroventricular infusions of vasopressin and AngII. We maintained 12-week-old male Sprague-Dawley rats either on tap water (control) or on water containing simvastatin (20, 40 or 60 mg/L) for 4 weeks. Subsequently, we measured arterial blood pressure and heart rate (HR) at baseline and after air-jet stress or intracerebroventricular infusions over 30 s of 10 ng AngII, 20 ng vasopressin or their antagonists (10 μg losartan and 400 ng d(CH2)5[Tyr(Me)2,Ala-NH29] vasopressin, respectively).
  3. There were no significant differences between the control and simvastatin groups in terms of baseline mean arterial blood pressure (MAP) and HR. In rats given 60 mg/L simvastatin, the hypertensive response to air-jet stress was significantly smaller than in controls, as was the increase in MAP in response to AngII. In contrast, there was no significant difference between the groups in terms of the hypertensive response to vasopressin.
  4. These findings show that simvastatin affects the hypertensive response to air-jet stress and provide evidence that statins may affect the brain's regulation of the circulatory system.