一氧化氮对犬下食管括约肌压力的作用

目的 :应用苄基二甲基十四烷氯化铵 (benzyldim ethyltetradecyl amm onium chloride,BAC)建立犬下食管括约肌(L ES)无神经动物模型 ,研究一氧化氮 (NO)对 L ES压力的作用。方法 :将 BAC环周注入犬 L ES,对照组注入等量生理盐水 ,均于注射前及注射后 6周测定 L ES压力 ;并观察 L -精氨酸、D -精氨酸、硝普钠及一氧化氮合酶 (NOS)抑制剂 N-硝基 - L -精氨酸 (L - NNA)对 L ES压力的影响 ;此外还测定了两组犬 L ES中 NO含量和 NOS活性。结果 :BAC处理组 L ES压力 [(4 2 .43±4.19) m m Hg,1m m Hg=0 .133 k Pa]显著高于对照组 [(2 2 .71± 5 .19) mm Hg]。 L -精氨酸可使对照组 L ES压力降低 ;L - NNA使其增高 ,但对 BAC处理组 L ES压力均无影响。硝普钠可降低两组犬 L ES压力。对照组 L ES中 NO为 (6 .0 5 8± 2 .0 6 7)μm ol/g,NOS为 (1.45 8± 0 .146 ) U /mg;而 BAC处理组 NO为 (1.797± 0 .873)μmol/g,NOS为 (0 .46 3± 0 .0 39) U /m g,均较对照组显著降低 (P<0 .0 1)。 结论 :BAC可使犬 L ES压力增高 ,其机制可能与 L ES局部 NO减少有关。

Effect of nitric oxide (NO) on lower esophageal sphincter pressure in dogs

Objective: To develop a denervated dog model in the loweresophageal sphincter(LES) and to investigate the role of nitric oxide(NO). Methods: Benzyldimethyltetradecyl ammonium chloride(BAC) was endoscopically injected circumferentially into the LES in 10 adult dogs and saline was injected in 10 adult dogs as control. Pre-injection and 6 weeks after injection, manometry was performed. With L-arginine, D-arginine, N-nitro-L-arginine(L-NNA) and sodium nitroprusside(SNP), pharmacological responses of the LES pressure(LESP) were observed and the content of NO and the activity of nitric oxide synthase (NOS) in LES were determined. Results: LESP in BAC-treated dogs was significantly higher than that in control [(42.43±4.19) mmHg vs (22.71±5.19) mmHg]. L-arginine significantly decreased and L-NNA increased LESP in control, but L-NNA had no effects on BAC-treated dogs. SNP reduced LES pressure in all dogs. The content of NO and the activity of NOS in LES of BAC-treated dogs were markedly lower than that in control [NO:(1.797±0.873) μmol/g vs (6.058±2.067) μmol/g), NOS: (0.463±0.039) U/mg vs (1.458±0.146) U/mg]. Conclusion: Injection of BAC into LES can increase LESP， and the elevated pressure of LES in dog may be closely related to the loss of NO in LES.