Coronary vascular effects of endothelin-1 during arterial hypotension.
Endothelin-1 (ET-1) effects on left circumflex coronary artery (LCCA) flow, systemic arterial pressure, heart rate, and left ventricle (LV) pressure and dP/dt were recorded in five anesthetized goats under control conditions and during arterial hypotension. Hypotension, induced by mechanical constriction of the inferior vena cava, reduced mean systemic arterial pressure from 92 +/- 4 to 59 +/- 4 mm Hg (p < 0.002), LCCA flow from 26 +/- 4 to 17 +/- 3 ml/min (p < 0.01), systolic LV pressure from 108 +/- 2.5 to 79 +/- 2 mm Hg (p < 0.002), and peak systolic LV dP/dt from 1,500 +/- 106 to 990 +2- 130 mm Hg/s (p < 0.02). Heart rate did not change (p > 0.05). ET-1 (0.01-0.1 nmol) injected into LCCA reduced LCCA flow in a dose-dependent manner without affecting the other variables recorded during control periods (C) and hypotension (H). The percentage reductions of LCCA flow by ET-1 were: for 0.01 nmol, 4.5 +/- 2 (C) vs. 11 +/- 2 (H) (p < 0.05); for 0.03 nmol, 15 +/- 2 (C) vs. 32 +/- 4 (H) (p < 0.05); and for 0.1 nmol, 44 +/- 5 (C) vs. 67 +/- 5 (H) (p < 0.05). This indicates that the coronary vasoconstrictor effects of ET-1 are increased during hypotension. Therefore, heart ischemia may be aggravated in situations of arterial hypotension with increased plasma concentrations of ET-1.
Fernández
N
N
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma, Madrid, Spain.
García-Villalón
A L
AL
Monge
L
L
Gómez
B
B
Diéguez
G
G
D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects* / Q000502:physiology; D016232:Endothelins / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006041:Goats; D007022:Hypotension / Q000503:physiopathology*; D066298:In Vitro Techniques
D016232:Endothelins