L-NNA对肾神经传入的内脏-减压反应的影响

Effects of L-NNA on the Viscero-Depressor Response from Renal Afferent Nerve

目的观察静脉注射一氧化氮合酶(NOS)抑制剂N-硝基-L-精氨酸(L-NNA)对肾神经传入的内脏-减压反应的影响并探讨其中枢机制。方法用电刺激大鼠肾神经传入纤维的方法模拟内脏痛,比较静脉注射L-NNA前后刺激肾神经传入纤维时血压的变化情况。结果用药后基础血压升高(P<0.01)。用药前刺激肾神经时为降压反应,平均动脉压下降(13.54±4.37)mmHg(P<0.01),脉压减小,心率减慢;而用药后刺激肾神经时,平均动脉压升高(5.52±6.33)mmHg(P<0.01),脉压增大,心率加快;若注射L-NNA之前先注射L-精氨酸(L-Arg),无论是基础血压还是刺激后的血压变化,与用药前的自身对照组相比,差异均无显著性(P>0.05)。结论在大鼠身上刺激肾神经传入纤维可引起内脏-减压反应;并发现L-NNA对上述反应有翻转作用,这一作用的机制可能是由于抑制了内源性一氧化氮的生成。

Objective To observe the effect of intravenous injection L-NNA on the viscero-depressor response from renal afferent nerve and to probe into the central mechanism of the reversion of the response induced by the intravenous injection of L-NNA. Methods The visceral pain was imitated by electric stimulation of the renal nerve.The basal blood pressure(BP) and the pressure responses to the electric stimulation were observed before or after intravenous injection of L-NNA. Results The basal BP was elevated after injection of L-NNA (P<0.01).When the nerve was stimulated without injection of L-NNA,BP dropped down (13.54±4.37)mmHg (P<0.01),the pulse pressure became smaller and the heart rate became slower,while the response of BP was elevated (5.52±6.33)mmHg (P<0.01) and the pulse pressure became larger,the heart rate became faster after injection of L-NNA.If L-arginine was injected before L-NNA,both the basal BP and responsive BP unchanged(P>0.05).Conclusion The viscero-depressor response was induced by stimulating the renal nerve in rats,which would be reversed by L-NNA,due to the inhibition of the intrinsic nitric oxide synthesis.