Hydralazine dilates large epicardial coronary arteries in conscious dogs through an endothelium-independent mechanism.
In chronically instrumented conscious dogs, hydralazine (30-300 micrograms/kg) and nitroglycerin (NTG 0.03-10 micrograms/kg) dose-dependently dilated large epicardial coronary arteries. Simultaneously, hydralazine also dose-dependently dilated small coronary arteries, whereas a similar effect was observed only after NTG > 0.3 microgram/kg. When large coronary arteries were deendothelialized by a balloon angioplasty catheter, dilation of large coronary arteries in response to acetylcholine (ACh 0.3 microgram/kg) and to reactive hyperemia was reduced by 87 and 95%, respectively. In contrast, vasodilation of large coronary arteries induced by hydralazine and NTG was only minimally and similarly affected (-19% for both drugs). These findings demonstrate that in vivo hydralazine-induced dilation of large coronary arteries is endothelium independent.
Drieu la Rochelle
C
C
Département de Pharmacologie, Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France.
Dubois-Randé
J L
JL
Hittinger
L
L
Richard
V
V
Berdeaux
A
A
Giudicelli
J F
JF
D000800:Angioplasty, Balloon; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000033:anatomy & histology / Q000187:drug effects*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000502:physiology*; D006830:Hydralazine / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D006830:Hydralazine; D005996:Nitroglycerin