Acetylcholine causes endothelium-dependent contraction of mouse arteries.
The goal of this study was to determine whether acetylcholine evokes endothelium-dependent contraction in mouse arteries and to define the mechanisms involved in regulating this response. Arterial rings isolated from wild-type (WT) and endothelial nitric oxide (NO) synthase knockout (eNOS(-/-)) mice were suspended for isometric tension recording. In abdominal aorta from WT mice contracted with phenylephrine, acetylcholine caused a relaxation that reversed at the concentration of 0.3-3 microM. After inhibition of NO synthase [with N(omega)-nitro-l-arginine methyl ester (l-NAME), 1 mM], acetylcholine (0.1-10 microM) caused contraction under basal conditions or during constriction to phenylephrine, which was abolished by endothelial denudation. This contraction was inhibited by the cyclooxygenase inhibitor indomethacin (1 muM) or by a thromboxane A(2) (TxA(2)) and/or prostaglandin H(2) receptor antagonist SQ-29548 (1 microM) and was associated with endothelium-dependent generation of the TxA(2) metabolite TxB(2.) Also, SQ-29548 (1 microM) abolished the reversal in relaxation evoked by 0.3-3 microM acetylcholine and subsequently enhanced the relaxation to the agonist. The magnitude of the endothelium-dependent contraction to acetylcholine (0.1-10 microM) was similar in aortas from WT mice treated in vitro with l-NAME and from eNOS(-/-) mice. In addition, we found that acetylcholine (10 microM) also caused endothelium-dependent contraction in carotid and femoral arteries of eNOS(-/-) mice. These results suggest that acetylcholine initiates two competing responses in mouse arteries: endothelium-dependent relaxation mediated predominantly by NO and endothelium-dependent contraction mediated most likely by TxA(2).
Zhou
Yingbi
Y
Davis Heart and Lung Research Institute, College of Medicine and Public Health, The Ohio State University, 473 W. 12th Ave., Columbus, OH 43210, USA.
Varadharaj
Saradhadevi
S
Zhao
Xue
X
Parinandi
Narasimham
N
Flavahan
Nicholas A
NA
Zweier
Jay L
JL
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects / Q000502:physiology; D002339:Carotid Arteries / Q000187:drug effects / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D005263:Femoral Artery / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019001:Nitric Oxide Synthase / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D014661:Vasoconstriction / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D000109:Acetylcholine