疑核注射L-精氨酸和7-硝基吲哚对大鼠心率变异性的影响

The Influence of HRV with L-arg and 7-NI in Rats

目的研究大鼠疑核(NA)心抑制区的一氧化氮(NO)对心率(HR)和心率变异性(HRV)的影响。方法Wistar大鼠20只,随机分为两组,对照组脑干NA心抑制区右侧注射L-精氨酸(L-arg)5.0nmol/L和生理盐水各0.5μL;实验组脑干NA心抑制区单侧注射L-arg5.0nmol/L和7-硝基吲哚(7-NI)2.0nmol/L各0.5μL,分析HRV的变化。结果NA心抑制区微量注射L-arg后与给药前相比,HR显著降低(P<0.01),时域指标:24h正常R-R间期标准差(SDNN)和24h相邻R-R间期标准差值的均方根(rMSSD)升高(P<0.05),频域指标LF和HF升高(P<0.01);LF/HF降低(P<0.01)。微量注射7-NI和生理盐水后与注射L-arg后相比,实验组HR升高(P<0.05),时域指标SDNN、rMSSD和频域指标LF和HF降低(P<0.01或P<0.05),LF/HF升高(P<0.05)。结论大鼠脑干NA心抑制区产生的NO可增强心迷走神经的活性。

Objective To study the effects of nitric oxide （NO） in cardioinhibtory sites within the nucleus ambiguous （NA） on heart rate （HR） and heart rate variability （HRV） in anaesthetized rats. Methods Twenty healthy male Wistar rats were randomly divided into two groups： Control group （L - arg 5.0 nmol/L and saline 0.5 μL were injected into right cardioinhibtory sites, n = 10） ; Experiment group （L - arg 5.0 nmol/L and 7 - NI 2.0 nmol/L, 0.5/~L were injected into right cardioinhibtory sites, n = 10）. HRV was analyzed. Results After injections of L- arg into cardioinhibtory sites in NA, HR decreased remarkably, SDNN and rMSSD of time domain increased, LF and HF of frequency domain increased and LF/HF decreased, compared with baseline, After injections of 7 - NI and saline into cardioinhibtory sites, HR increased significantly after microinjection 7 - NI, SDNN and rMSSD of time domain decreased; LF and HF of frequency domain decreased and LF/HF of frequency domain increased, compared with L - arg medication. Compared with saline medication, HR was higher after microinjection 7 - NI, SDNN and rMSSD of time domain and HF of frequency domain were lower than microinjection saline. Conclusion Nitric oxide produced from cardioinhibtory sites within the nucleus ambiguous of rats could increase activity of cardiac vagus.