title: Selective right, but not left, coronary endothelial dysfunction precedes development of pulmonary hypertension and right heart hypertrophy in rats.
abstract: We investigated a causal role for coronary endothelial dysfunction in development of monocrotaline (MCT)-induced pulmonary hypertension and right heart hypertrophy in rats. Significant increases in pulmonary pressure and right ventricular weight did not occur until 3 wk after 60 mg/kg MCT injection (34 +/- 4 vs. 19 +/- 2 mmHg and 37 +/- 2 vs. 25 +/- 1% septum + left ventricular weight in controls, respectively). Isolated right coronary arteries (RCA) showed significant decreases in acetylcholine-induced NO dilation in both 1-wk (33 +/- 3% with 0.3 microM; n = 5) and 3-wk (18 +/- 3%; n = 11) MCT rats compared with control rats (71 +/- 8%, n = 10). Septal coronary arteries (SCA) showed a smaller decrease in acetylcholine dilation (55 +/- 8% and 33 +/- 7%, respectively, vs. 73 +/- 8% in controls). No significant change was found in the left coronary arteries (LCA; 88 +/- 6% and 81 +/- 6%, respectively, vs. 87 +/- 3% in controls). Nitro-L-arginine methyl ester-induced vasoconstriction, an estimate of spontaneous endothelial NO-mediated dilation, was not significantly altered in MCT-treated SCA or LCA but was increased in RCA after 1 wk of MCT (-41 +/- 6%) and decreased after 3 wk (-18 +/- 3% vs. -27 +/- 3% in controls). A marked enhancement to 30 nM U-46619-induced constriction was also noted in RCA of 3-wk (-28 +/- 6% vs. -9 +/- 2% in controls) but not 1-wk (-12 +/- 7%) MCT rats. Sodium nitroprusside-induced vasodilation was not different between control and MCT rats. Together, our findings show that a selective impairment of right, but not left, coronary endothelial function is associated with and precedes development of MCT-induced pulmonary hypertension and right heart hypertrophy in rats.
authors.affiliation: Dept. of Pharmacology and Toxicology, Univ. of Alabama at Birmingham, 1530 3rd Ave. S., Birmingham, AL 35294-0019, USA.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Sun
authors.forename: David D
authors.initials: DD
authors.lastname: Ku
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006976:Hypertension, Pulmonary / Q000139:chemically induced / Q000209:etiology*; D017380:Hypertrophy, Right Ventricular / Q000139:chemically induced / Q000209:etiology*; D008297:Male; D016686:Monocrotaline; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D009569:Nitric Oxide; D016686:Monocrotaline; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester