Forearm vasodilator response to angiotensin II in elderly women receiving candesartan: role of AT2- receptors

Abstract

The effects of angiotensin II (Ang II) and the Ang II type 2 (AT₂) receptor antagonist, PD 123319, on forearm vascular resistance (FVR) were studied in elderly women during Ang II type 1 (AT₁) receptor antagonist therapy. Eight women, aged 67±6 years, received the AT₁-receptor antagonist, candesartan, 8—16 mg once-daily for three weeks. FVR responses to intra-brachial arterial infusions of Ang II (8—32 ng/minute) during the co-infusion of PD 123319 (8 µg/minute) or placebo were measured at the end of the second and third weeks in a randomised, double-blind, crossover study.

Ang II produced dose-dependent reductions in FVR during both the placebo and PD 123319 infusions. However, FVR was significantly higher during PD 123319 infusions than during placebo infusions. Candesartan therapy unmasks a vasodilator response to Ang II in forearm resistance vessels of elderly women. AT₂-receptor blockade increases FVR, but does not prevent vasodilator responses to Ang II, suggesting that other vasodilator mechanisms may also be involved.

Keywords

angiotensin II candesartan elderly PD 123319 angiotensin type 2 receptors

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