Differential effects of nitric oxide synthase inhibitors in rats.
- Author:
Jun Hee LEE
1
;
Chang Yell SHIN
;
Bong Su KANG
;
Ji Hoon JEONG
;
Kyeong Bum CHOI
;
Young Sil MIN
;
Jin Hak KIM
;
In Hoi HUH
;
Uy Dong SOHN
Author Information
1. Department of Pharmacology, College of Pharmacy, Chung Ang University, 221 Heuksuk-dong, Dongjak-gu, Seoul, South Korea.
- Publication Type:Original Article
- MeSH:
Acetylcholine;
Animals;
Aorta, Thoracic;
Arginine;
Neural Conduction;
NG-Nitroarginine Methyl Ester;
Nitric Oxide Synthase*;
Nitric Oxide*;
Nitroarginine;
omega-N-Methylarginine;
Phenylephrine;
Platelet Activating Factor;
Rats*;
Sciatic Nerve;
Superoxide Dismutase
- From:The Korean Journal of Physiology and Pharmacology
2000;4(2):99-104
- CountryRepublic of Korea
- Language:English
-
Abstract:
We investigated the action of NOS inhibitors on NOS in rats. Both of nitric oxide synthase inhibitors, NG-monomethyl-L-arginine (L-NMMA, 3 micrometer) or NG-nitro-L-arginine methylester (L-NAME, 30 micrometer), augmented phenylephrine (PE, 10-7 M)-induced contraction which was inhibited by acetylcholine (ACh) in rat thoracic aorta. This augmentation by L-NAME or L-NMMA was attenuated with the treatment of NO precursor, arginine. ACh, however, decreased the augmentation induced by L-NMMA, but not by L-NAME. Superoxide dismutase (SOD, 50 u/ml) potentiated an inhibitory effect of ACh on the PE (10-7 M)-induced contraction. It has been known that platelet activating factor itself induces iNOS. Platelet activating factor (PAF, 10-7 M) inhibited PE (10-7 M)-induced contraction. Pretreatment with L-NMMA (30 mM) or L-NAME (30 mM) significantly blocked the inhibitory action of PAF on PE-induced contraction. L-NMMA (100 mM) or L-NAME (100 mM) reduced nerve conduction velocity (NCV) relevant to nNOS in rat sciatic nerve. ACh attenuated the reduction of NCV by L-NMMA-, but not by L-NAME-induced reduction of NCV. These results suggest that L-NMMA and/or L-NAME have different action on three types of NOS in rats.
