Effects of nitro-L-arginine on endothelium-dependent relaxation of canine cerebral arteries.
1. The effect of NG-nitro-L-arginine (NO2Arg) on the relaxation of canine basilar artery was investigated and compared with those of middle cerebral and femoral arteries. 2. NO2Arg (10(-7)-3 x 10(-5) mol/L) inhibited the substance-P (Sub-P; 10(-12)-10(-8) mol/L) induced relaxation in the basilar artery precontracted with prostaglandin F2 alpha (PGF2 alpha; 10(-5) mol/L) or KCl (10(-2) mol/L) in a concentration-dependent manner and a ratio of the maximum inhibition by NO2Arg (3 x 10(-5) mol/L) was more than 90%. 3. The relaxation induced by A23187 (10(-9)-3 x 10(-6) was also abolished by NO2Arg (3 x 10(-5) mol/L), but that by glyceryl trinitrate (GTN; 10(-9)-3 x 10(-5) mol/L) was not, in the basilar artery precontracted with PGF2 alpha (10(-5) mol/L). NG-nitro-D-arginine (NO2ArgD; 3 x 10(-5) mol/L) did not affect the relaxation induced by Sub-P (10(-12)-10(-8) mol/L). 4. L-arginine (L-Arg; 3 x 10(-5)-10(-4) mol/L) did not inhibit Sub-P (10(-12)-10(-8) mol/L) induced relaxation in the basilar artery. Pretreatment of L-Arg (10(-4) mol/L) reversed the relaxation inhibited by NO2Arg (3 x 10(-6) mol/L) in the arteries. 5. NO2Arg (3 x 10(-5) mol/L) inhibited the Sub-P (10(-12)-10(-8) mol/L) induced relaxation in the canine middle cerebral artery as much as in the basilar artery.(ABSTRACT TRUNCATED AT 250 WORDS)
Ohta
F
F
Department of Pharmacology, Shimane Medical University, Izumo, Japan.
Kobayashi
Y
Y
Shinozuka
K
K
Shimoura
K
K
Hattori
K
K
Moritake
K
K
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001488:Basilar Artery / Q000187:drug effects* / Q000502:physiology; D000001:Calcimycin / Q000494:pharmacology; D002536:Cerebral Arteries / Q000187:drug effects* / Q000502:physiology; D015237:Dinoprost / Q000494:pharmacology; D004285:Dogs; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005263:Femoral Artery / Q000187:drug effects / Q000502:physiology; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D019335:Nitroarginine; D013373:Substance P / Q000494:pharmacology
D019335:Nitroarginine; D009569:Nitric Oxide; D013373:Substance P; D000001:Calcimycin; D001120:Arginine; D015237:Dinoprost