Forearm vasodilator response to angiotensin II in elderly women receiving candesartan: role of AT(2)- receptors.

The effects of angiotensin II (Ang II) and the Ang II type 2 (AT(2)) receptor antagonist, PD 123319, on forearm vascular resistance (FVR) were studied in elderly women during Ang II type 1 (AT(1)) receptor antagonist therapy. Eight women, aged 67 +/- 6 years, received the AT(1)-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 microg/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. AT(2)-receptor blockade increases FVR, but does not prevent vasodilator responses to Ang II, suggesting that other vasodilator mechanisms may also be involved.