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.
Phoon
Stephen
S
Department of Aged Care, St George Hospital, UNSW, Kogarah, NSW, Australia.
Howes
Laurence Guy
LG
D000368:Aged; D000804:Angiotensin II / Q000494:pharmacology*; D057911:Angiotensin Receptor Antagonists; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001562:Benzimidazoles / Q000494:pharmacology*; D001713:Biphenyl Compounds; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005542:Forearm / Q000098:blood supply*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D008875:Middle Aged; D011725:Pyridines / Q000494:pharmacology; D044140:Receptor, Angiotensin, Type 1; D012039:Regional Blood Flow / Q000187:drug effects; D013777:Tetrazoles / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*
D057911:Angiotensin Receptor Antagonists; D000959:Antihypertensive Agents; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D007093:Imidazoles; D011725:Pyridines; D044140:Receptor, Angiotensin, Type 1; D013777:Tetrazoles; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C073402:PD 123319; C081643:candesartan