Role of nitric oxide on the endothelium-dependent vasodilation in newborn piglet cerebral arteries.
1. The present study was undertaken to determine whether endothelial nitric oxide (NO) is involved in the endothelium-dependent vasodilation elicited by bradykinin (BK) in rings of newborn (1-7-day-old) piglet cerebral arteries precontracted with KCl (25 mM). 2. In these rings, BK (10(-10)-10(-6) M) induced concentration-dependent relaxation. The preincubation with the precursor of NO synthesis, L-arginine (10(-4) M), reduced KCl-induced contraction and increased the BK relaxation. However, preincubation with the NO synthase inhibitor, NG-nitro-L-arginine-methyl ester (L-NAME; 3 x 10(-5) M), increased KCl contraction and basal tone, and inhibited BK relaxation. 3. These results suggest that the endothelium of these arteries possesses the ability to produce NO, either basal or stimulated by agents like BK.
Servicio de Pediatría, (Unidad de Neonatología), Hospital Virgen de la Luz, Cuenca, Spain.
J
J
Martínez-Orgado
M
M
Salaices
M A
MA
Rodríguez-Martínez
C F
CF
Sánchez-Ferrer
J
J
Marín
D000818:Animals; D000831:Animals, Newborn; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D002536:Cerebral Arteries / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D066298:In Vitro Techniques; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000502:physiology*; D013552:Swine; D014664:Vasodilation / Q000187:drug effects*
D009569:Nitric Oxide; D001120:Arginine; D001920:Bradykinin; D019331:NG-Nitroarginine Methyl Ester