Nitric oxide does not mediate flow induced endothelium dependent arterial dilatation in the cat.
OBJECTIVE
The aim was to determine whether the endothelium derived nitric oxide formed from L-arginine is the factor which mediates flow induced dilatation of conduit arteries.


METHODS
Changes in diameter of feline femoral artery caused by blood flow rate increases, acetylcholine, and ATP were recorded during perfusion with blood in situ before and after the inhibition of endothelium derived nitric oxide synthesis by NG-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine. Fourteen anaesthetised cats of either sex, weight 2.6-3.9 kg, were used for the studies.


RESULTS
Intravenous administration of NG-nitro-L-arginine methyl ester and NG-monoethyl-L-arginine in doses 10 and 30 mg.kg-1 evoked a rise in mean systemic arterial pressure, constriction of the femoral artery, and considerable decrease in acetylcholine and ATP induced dilatation. However, it did not affect the dilator response induced by increased blood flow rate.


CONCLUSIONS
Flow induced endothelium dependent arterial dilatation is not mediated by nitric oxide or, if nitric oxide is still released in response to flow rate increase, it has a source distinct from L-arginine.
Melkumyants
A M
AM
Department of Circulation Biomechanics and Control, Cardiology Research Centre, Moscow, Russia.
Balashov
S A
SA
Klimachev
A N
AN
Kartamyshev
S P
SP
Khayutin
V M
VM
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D004730:Endothelium, Vascular / Q000378:metabolism*; D005260:Female; D005263:Femoral Artery / Q000187:drug effects / Q000502:physiology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000378:metabolism*; D012039:Regional Blood Flow / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D019323:omega-N-Methylarginine
D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester