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

为了评估副交感神经系统和内皮来源的松弛因子在拔牙过程中对低血压的作用，我们测量了年轻和老年患者（研究1）以及血压正常和高血压患者（研究2）的血压（BP）、脉搏率和心率变异性的变化。该研究包括20名年轻人，20名老年人（研究1），18名原发性高血压患者，18名年龄和性别匹配的正常对照组（研究2），他们在我院进行了拔牙手术。采用动态心电图监测确定牙科手术前和手术中R-R变异性的功率谱。计算低频（LF: 0.041 ~ 0.140 Hz）、高频（HF: 0.140 ~ 0.500 Hz）和总频谱功率（TF: 0.000 ~ 4.000 Hz），分别以低频与高频的比值和高频相对于TF的百分比（%HF: HF/TF × 100）作为交感神经和副交感神经活动的指标。在拔牙期间，还抽取了大量血液，以测量血液中NO_x和儿茶酚胺的浓度（研究3）。研究：研究1受试者的基线血压为121/70 mmHg，含有肾上腺素的局部麻醉利多卡因（1:8 000）使血压升高，拔牙时血压进一步升高至132/173 mmHg。血压升高在40岁以上的受试者中尤为明显。局部麻醉对年轻患者HF百分比有抑制作用，而局部麻醉对年轻患者LF/ HF百分比有增强作用，对老年患者有抑制作用。研究2：高血压患者静息血压为149/ 85mmHg，明显高于正常患者（119/71 mmHg）。两组的基线脉搏率相似。两组患者拔牙时血压升高；然而，两组之间的血压变化没有差异。局麻可显著降低正常血压患者的HF %，而高血压患者在局麻加拔牙时，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，但没有改变NO_x的浓度。结果表明，拔牙引起的升压反应在老年受试者中大于年轻受试者，而在正常血压和高血压患者中相似。在牙科手术中，心脏副交感神经和交感神经系统在年轻人和老年人之间可能不同，在血压正常的人和高血压患者之间也可能不同。内皮源性舒张因子NO_s可能在口腔治疗过程中血压变化中起不主要作用。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。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