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目的研究内源性和外源性一氧化氮 (NO)对动脉压力感受器反射的不同作用。方法静脉注射苯肾上腺素 (PE ,30 μg·kg- 1 ) ,改变大鼠血压 ,诱发动脉压力感受器反射。分别静脉注射硝普钠 (SNP ,1 0 .2 μg·kg- 1 )和L 精氨酸 (L Arg ,2 5mg·kg- 1 )以产生外源性和内源性NO ,静脉注射L NAME( 1 0mg·kg- 1 )抑制内源性NO的产生 ,并估测NO的产生或抑制对压力感受器敏感性的影响。结果与正常状态比较 ,L Arg使大鼠压力感受器反射敏感性 (Gmax)和血压 -心率拟合曲线斜率τ显著下降 [Gmax=- 1 .469± 0 .1 2 0beats/(min·mmHg)vs. - 0 .664± 0 .0 80beats/(min·mmHg) ,P <0 .0 1 ;τ =0 .0 86±0 .0 0 5vs .0 .0 4 9± 0 .0 0 7,P <0 .0 5 ]。SNP尽管也引起了上述参数的减小 ,但作用不显著。与L Arg和SNP的作用相反 ,L NAME导致了Gmax和τ的上升 ,但变化不显著。结论内源性和外源性NO对压力感受器反射的作用不同 ,内源性NO可能抑制压力感受器反射的敏感性。
Objective To investigate the different effects of endogenous and exogenous nitric oxide (NO) on the reflex of arterial baroreceptors. Methods Phenylephrine (PE, 30 μg · kg-1) was intravenously injected to change the blood pressure of rats and induce the reflex of arterial baroreceptors. Sodium nitroprusside (SNP, 102 μg · kg -1) and L Arg (25 mg · kg -1) were intravenously injected to produce exogenous and endogenous NO, intravenous injection of L NAME (10 mg · kg -1) inhibited the production of endogenous NO and estimated the effect of NO production or inhibition on baroreceptor sensitivity. Results Compared with the normal state, L Arg significantly decreased the baroreceptor reflex sensitivity (Gmax) and the slope of the fitted curve of blood pressure-heart rate [Gmax = -1.469 ± 0.12beats / (min · mmHg) vs .-0 .664 ± 0 .0 80beats / (min · mmHg), P <0 .0 1; τ = 0 .086 ± 0 .0 5vs .0. 0 4 9 ± 0 .0 0 7, P <0 .0 5]. Although SNP also caused the above parameters to decrease, the effect was not significant. In contrast to the effect of L Arg and SNP, L NAME resulted in an increase in Gmax and tau, but the change was insignificant. Conclusion Endogenous and exogenous NO have different effects on baroreceptor reflex. Endogenous NO may inhibit the sensitivity of baroreceptor reflex.