Role of parasympathetic nervous system and endothelium-derived relaxing factor on hypotension during tooth extraction

为了评价副交感神经系统和内皮松弛因子在拔牙期间低血压中的作用，我们测量了年轻和老年患者(研究1)以及正常血压和高血压患者(研究2)的血压(BP)、脉率和心率变异性的变化。研究对象包括20名青年和20名老年受试者(研究1)，18名高血压患者和年龄、性别匹配的18名正常血压对照组(研究2)。用动态心电图监测牙科手术前后R-R变异性的功率谱。计算低频(低频：0.041~0.140 Hz)、高频(高频：0.140~0.500 Hz)和总谱功率(Tf：0.000~4.000 HZ)，并以低频与高频的比值和高频与Tf的百分比(%HF：HF/Tfx100)作为交感和副交感活动的指标。血液也是在Volu…中抽取的研究1受试者的基线血压为121/70毫米汞柱，含肾上腺素的局麻药利多卡因(1：80000)使血压升高，在拔牙期进一步升高至132/173毫米汞柱。血压升高在40岁以上的受试者中显著。局麻药注射可抑制年轻患者的HF百分比，而青年患者的LF/HF在局麻时升高，而老年患者的LF/HF则受到抑制。研究二：高血压病患者的静息血压为149/85 mm Hg，显著高于正常血压患者的119/71 mm Hg。两组患者的基线脉搏频率相似。两组患者拔牙时血压均升高，但两组间血压变化无差异。局麻药给药可显著降低血压正常患者的%HF，而高血压患者在局麻药给药和拔牙期间的LF/HF显著降低。研究3：牙科手术增加了血中肾上腺素和去甲肾上腺素的浓度，但不改变NO_x的浓度。这些结果表明，老年人拔牙引起的升压反应大于年轻人，而正常血压和高血压患者的升压反应相似。牙科手术中的心脏副交感神经系统和交感神经系统在年轻和老年受试者之间可能不同，在血压正常的受试者和高血压患者中也可能不同。内皮源性松弛因子，如NO_S，可能在牙科治疗过程中对血压的影响不起主要作用。高血压和衰老都可能抑制牙科手术引起的交感神经活动的增加。较少

To evaluate the role of parasympathetic nervous system and endothelium- derived relaxing factor on hypotension during dental extraction, we have measured the changes in blood pressure (BP), pulse rate, and heart rate variability in young and old patients (study 1) as well as in normotensive and hypertensive subjects (study 2). The study included 20 young, 20 old subjects (study 1), 18 essential hypertensives and age and sex matched 18 normotensive controls (study 2) who underwent tooth extraction at our hospital. Holter electrocardiographic monitoring was used to determine the power spectrum of R-R variability before and during dental surgery. The low frequency (LF : 0.041 to 0.140 Hz), high frequency (HF : 0.140 to 0.500 Hz), and total spectral powers (TF : 0.000 to 4.000 Hz) were calculated, and the ratio of LF to HF and percentage of HF relative to TF(%HF : HF/TF x 100) were used as indexes of sympathetic and parasympathetic activities, respectively. The blood was also drawn in volu … More nteer during dental extraction to measure blood NO_x and catecholamines concentrations (study 3).Studyl : The baseline BP for study 1 subjects was 121/70 mmHg, Local anesthetic lidocaine containing epinephrine (1 : 80000) increased BP, which was further increased up to 132/173 mmHg during dental extraction. The BP elevation was prominent in subjects older than 40 years old. The percent HF was suppressed by local anesthetic injection in younger patients, while LF/ HF was enhanced in young subjects but suppressed in old subjects during local anesthesia. Study 2 : The resting BP was 149/ 85mmHg for hypertensive patients, which was significantly higher than that for normotensive patients (119/71 mmHg). The baseline pulse rate was similar in both groups. BP increased during tooth extraction in both groups ; however, changes in BP did not differ between two groups. Administration of local anesthetic significantly decreased the %HF in normotensive patients In contrast, the LF/HF significantly decreased during the administration of local anesthesia and tooth extraction in hypertensive patients. Study 3 : Dental surgery increased blood concentrations of adrenaline and noradrenaline, but did not change the concentration of NO_x.These results showed that pressor response induced by tooth extraction was greater in older subjects than in younger subjects, while it was similar between normotensive and hypertensive patients. Cardiac parasympathetic and sympathetic nervous systems during dental surgery may be different between young and old subjects, and also differ in normotensive subjects and hypertensive patients. Endothelium- derived relaxing factor as NO_s may not play major roles on BP changes during dental treatment. Both hypertension and aging might suppress increases in sympathetic activity induced by dental surgery. Less