Oliveira R B, Matsuda N M, Antoniolli A R, Ballejo G
Departamento de Clínica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil.
Braz J Med Biol Res. 1992;25(8):853-5.
The aim of the present study was to investigate in vitro the effect of NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, on neurogenic relaxation of human lower esophageal sphincter (LES) and distal pylorus (DP) circular muscle strips induced by electrical field stimulation (EFS). Muscle strips obtained from 5 patients who underwent total gastrectomy were suspended in 10-ml organ baths containing Krebs solution for recording isometric tension. L-NAME (30 microM) reduced the amplitude of the EFS-induced relaxation by 85 +/- 9% (N = 3) in the LES and by 52 +/- 16% (N = 3) in the DP but did not affect sodium nitroprusside-induced relaxation. L-Arginine (300 microM) partially reversed the L-NAME inhibition in the LES and totally in the DP. These findings suggest a role for L-arginine-derived NO in the nerve-mediated NANC relaxation of the human LES and DP.
本研究的目的是在体外研究一氧化氮（NO）合酶抑制剂NG-硝基-L-精氨酸甲酯（L-NAME）对电场刺激（EFS）诱导的人食管下括约肌（LES）和幽门远端（DP）环形肌条神经源性舒张的影响。从5例行全胃切除术的患者获取的肌条，悬挂于含Krebs溶液的10 ml器官浴槽中，记录等长张力。L-NAME（30 μM）使LES中EFS诱导的舒张幅度降低85±9%（N = 3），使DP中降低52±16%（N = 3），但不影响硝普钠诱导的舒张。L-精氨酸（300 μM）部分逆转了L-NAME在LES中的抑制作用，在DP中则完全逆转。这些发现提示L-精氨酸衍生的NO在人LES和DP的神经介导非肾上腺素能非胆碱能（NANC）舒张中起作用。
