Role of endothelium-derived nitric oxide and adenosine in functional myocardial hyperemia.
To investigate the role of endothelium-derived nitric oxide (EDNO) and adenosine in functional myocardial hyperemia, we examined the effect of NG-nitro-L-arginine (L-NNA) and 8-p-sulfophenyltheophylline (8-SPT) on coronary vasodilation in response to increased myocardial oxygen consumption in pentobarbital sodium-anesthetized dogs. L-NNA significantly attenuated the increase in coronary conductance from 28 +/- 6 to 16 +/- 2% with atrial pacing, from 69 +/- 5 to 36 +/- 6% with isoproterenol, and from 25 +/- 6 to 9 +/- 4% with constriction of the aorta. 8-SPT given alone attenuated the increase in coronary conductance to the same extent as L-NNA. The combined administration of L-NNA and 8-SPT did not further change coronary conductance. These findings suggest that EDNO and adenosine play an important role in functional hyperemia. EDNO-induced functional hyperemia appears to be dependent on adenosine receptor activation.
Maekawa
K
K
Department of Cardiovascular Medicine, Okayama University Medical School, Japan.
Saito
D
D
Obayashi
N
N
Uchida
S
S
Haraoka
S
S
D000241:Adenosine / Q000502:physiology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006940:Hyperemia / Q000503:physiopathology*; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D019335:Nitroarginine; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects
D019335:Nitroarginine; D009569:Nitric Oxide; C031433:8-(4-sulfophenyl)theophylline; D001120:Arginine; D013806:Theophylline; D000241:Adenosine