title: Hypertension decreases small arteriole responses to acetylcholine in skeletal muscle.
abstract: Television microscopy was used to quantitate in vivo the responses of skeletal muscle small arterioles to acetylcholine. Five groups of rats were used: normotensive and one (1K1C)- and two (2K1C)- kidney one clip renovascular hypertensive Sprague-Dawley rats (SDR), as well as WKY normotensive and spontaneously hypertensive (SHR) rats. Third-order arterioles dilated to acetylcholine with an EC50 of 3 x 10(-7) M in SDR and 10(-6) M in WKY animals. In contrast, the concentration-response curve to acetylcholine was shifted to the right (less reactive) by 100 fold in the 1K1C- and by 1000 fold in the 2K1C-hypertensives. The dose-responsive curve to acetylcholine was shifted 10-fold to the right in the SHR's compared to the WKY's. Because acetylcholine acts through endothelium-dependent mechanisms and because maximal vasodilation could be induced by an endothelium-independent vasodilator, Na-nitroprusside, in all but the 2K1C-group, we conclude that different forms of hypertension interfere to a variable degree with endothelium-dependent vasodilator mechanisms in the skeletal muscle microcirculation.
authors: Center for Applied Microcirculatory Research, University of Louisville, KY 40292.
authors: A S
authors: AS
authors: Lübbe
authors: P D
authors: PD
authors: Harris
authors: N L
authors: NL
authors: Alsip
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006978:Hypertension, Renovascular / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D009132:Muscles / Q000098:blood supply*; D009599:Nitroprusside / Q000494:pharmacology; D009994:Osmolar Concentration; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D014664:Vasodilation
chemical_list: D009599:Nitroprusside; D000109:Acetylcholine