NO对家兔Oddi括约肌肌电活动和血压的影响

EFFECT OF NITRIC OXIDE ON THE MYOELECTRIC ACTIVITY OF SPHINCTER OF Oddi AND ARTERIAL BLOOD PRESSURE OF RABBIT

应用32只家兔观察一氧化氮（NO）对Qddi括约肌（SO）肌电和血压的影响。静脉注射NO合酶抑制剂NC-硝基-L-精氨酸（L-NNA），可见SO肌电振幅增大和血压升高，L-NNA所致的肌电活动增强可被L-精氨酸（L-arg）反转，而L-NNA所致的血压升高却未因L-arg的应用而下降。静脉注射能直接释放NO的药物硝普钠（SNP），引起SO肌电振幅、频率以及血压明显降低，而且存在明显的量效关系。上述结果提示：（1）在正常生理情况下，NO对SO运动发挥重要的抑制性调控作用，对血管平滑肌具有一定的舒张作用；（2）不同组织对L-ary的反应性存在差异；（3）体内NO水平升高，可明显抑制SO肌电的产生，同时使血压显著降低。

Thirty-two rabbits were used to investigate the effect of nitric oxide (NO) on the myoelectric activity of the sphincter of Oddi (SO) and arterial blood pressure. Intravenous infusion of NG-nitro-L-arginine(L-NNS), an inhibitor of nitric cxide synthase (NOS) ) caused increase in SO phasic wave amplitude and arterial blood pressure. The increase in SO phasic wave amplitude by infusion of L-NNA was reversed by L-arginine,but arterial blood pressure remained at a high level. It was observed that SO phasic wave amplitude, frequency and arterial blood pressure were significantly decreased by intravenously infusion of sodium nitroprusside (SNP), a substance producing NO. These Observations suggest that (1) NO inhibits the resting activity of SO and modulates relaxation of vascular smooth muscle; (2) different tissues show different responses to L-NNA and L-arginine.