Coronary effects of endothelin-1 and vasopressin during acute hypotension in anesthetized goats.
Coronary effects of endothelin-1 and vasopressin during acute hypotension, and the role of NO and prostanoids in these effects were examined in anesthetized goats. Left circumflex coronary artery flow was measured electromagnetically, and hypotension was induced by constriction of the caudal vena cava in animals non-treated (7 goats) or treated with the inhibitor of NO synthesis N(w)-nitro-L-arginine methyl esther (L-NAME, 5 goats), the cyclooxygenase inhibitor meclofenamate (5 goats) or both drugs (5 goats). Under normotension (22 goats), mean arterial pressure averaged 93 +/- 3 mm Hg and coronary vascular conductance (CVC) 0.37 +/- 0.025 ml/min/mm Hg. Endothelin-1 (0.01-0.3 nmol) and vasopressin (0.03-1 nmol), intracoronarily injected, dose-dependently decreased CVC by up to 56% for endothelin-1 and 40% for vasopressin. During hypotension in every condition tested, mean arterial pressure decreased to approximately 60 mm Hg, and CVC only decreased during hypotension pretreated with L-NAME (23%) or L-NAME + meclofenamate (34%). Under non-treated hypotension, the decreases in CVC by endothelin-1 were augmented approximately 1.5 fold, and those by vasopressin were not modified. This increase in CVR by endothelin-1 was not affected by L-NAME and was reversed by meclofenamate or L-NAME + meclofenamate. The coronary effects of vasopressin were not modified by any of these treatments. Therefore, acute hypotension increases the coronary vasoconstriction in response to endothelin-1 but not to vasopressin. This increased response to endothelin-1 may be related to both inhibition of NO release and release of vasoconstrictor prostanoids.
Fernández
Nuria
N
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo 2, 28029 Madrid, Spain.
Martínez
Ma Angeles
MA
García-Villalón
Angel Luis
AL
Monge
Luis
L
Diéguez
Godofredo
G
D000208:Acute Disease; D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003326:Coronary Circulation / Q000187:drug effects* / Q000502:physiology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000494:pharmacology*; D005260:Female; D006041:Goats; D007022:Hypotension / Q000378:metabolism / Q000503:physiopathology*; D008469:Meclofenamic Acid / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology; D014667:Vasopressins / Q000494:pharmacology*
D016861:Cyclooxygenase Inhibitors; D019332:Endothelin-1; D014667:Vasopressins; D009569:Nitric Oxide; D008469:Meclofenamic Acid; D019331:NG-Nitroarginine Methyl Ester