Vascular response to angiotensin II in XXXX : role of the baroreflex.

@entity455 @entity95 @entity536 @entity731 @entity165
High- @entity165 alimentation is associated with an induction of angiotensin-converting enzyme and angiotensin II receptor expression within the vascular wall of the aorta. Despite an enhanced pressure response to angiotensin II in @entity731 conscious @entity95 , angiotensin II-induced contraction was reduced in isolated @entity455 from the aorta and unchanged in those from the iliac artery. We, therefore, investigated whether @entity165 -induced @entity731 enhances overall vascular responsiveness to angiotensin II in intact animals and whether an altered arterial baroreflex sensitivity can explain the discrepancy between experiments in intact animals and isolated blood vessels. @entity95 were maintained on a high- @entity165 diet (2 g/d @entity165 plus 20 mL/d sunflower seed oil, n=11) or on a standard diet (n=12) for 12 weeks. Total serum lipids markedly increased (P<0.05). Tissue examinations 6 weeks after termination of the high- @entity165 diet revealed distinct @entity731 and elevated @entity165 content in the aorta (P<0.05). A high- @entity165 diet did not change baseline hemodynamic parameters. However, angiotensin II-induced increases in total peripheral resistance were larger in the @entity731 animals (86.3+/-13.0 versus 41.9+/-9.7 mm Hg. L(-1). min, P<0.05). In addition, the blood pressure pulse interval relationship was markedly reduced (slope: 0.80+/-0.14 versus 0. 49+/-0.06 ms/mm Hg, P<0.05), which suggested that the baroreflex blunted the angiotensin II response to a lesser extent in @entity731 animals. In conclusion, the overall vascular responsiveness to angiotensin II is increased in the @entity731 @entity95 as indicated by the larger increase in total peripheral resistance. An @entity536 may contribute to this effect.
