迷走神经和交感神经系统不同活动状态对心率变异性的影响

实验在氯醛糖加氨基甲酸乙酯麻醉的新西兰兔上进行。记录血压、心率、心电图并对心电Ｒ－Ｒ间期（ＲＲＩ）作功率谱密度（ＰＳＤ）分析。以单调性电刺激和低频率的波动性电刺激分别刺激减压神经、疑核和右侧迷走神经外周端,观察到低频率的波动性刺激对增加ＰＳＤ中低频成分（ＬＦ）的作用比单调性电刺激更大（Ｐ〈０．０５）。注射新福林仅在头一个２５６个心动周期时间内引起总变异性（ＴＶ）、ＬＦ、ＰＳＤ中高频成分（ＨＦ）。Ｌ     

电刺激迷走神经对蟾蜍心率和心率变异的影响

目的:观察不同频率迷走神经刺激对蟾蜍离体心脏的心率及心率变异的影响。方法:将蟾蜍心脏和右侧迷走交感干离体后,以不同频率电刺激神经,记录心电图曲线并作心率变异性(HRV)分析。结果:交感神经阻断后,电刺激迷走交感干,心率(HR)显著下降(P0.01),全部正常心动周期的标准差(SDNN)和相邻正常心动周期差值的均方根(RMSSD)显著升高(P0.01),不同频率刺激组之间没有明显差异;与对照组相比,各指标变化较大;给药组0.2Hz时高频(HF)显著升高(P0.01),低频/高频比值(LF/HF)明显降低(P0.05),0.8Hz时HF和LF/HF接近刺激前水平。结论:一定范围内增加刺激频率,迷走神经降低心率的作用增强;没有交感神经调节条件下的迷走神经对心率和心率变异的调节可能存在不同的机制。     

有氧锻炼对心脏自主神经调节的影响：心率变异性分析结果

为阐明有氧锻炼对心脏自主神经调节功能的影响,以及这种变化与卧位／坐位下体负压（ＬＢＮＰ）作用下的心率调节及立位耐力之间是否有一定联系,用频域、动态谱及非线性指标较全面分析了大学生有氧锻炼６个月前、后心率变异性（ＨＲＶ）的变化。结果表明：常规ＡＲ谱分析的批处理结果只能代表一段时间内ＨＲＶ信号的平均统计特性,方差大,得不出有显著意义的结果。而时变ＡＲ谱则可反映ＬＢＮＰ作用下心迷走撤除及交感激活的动态过程。非线性的β估计得不出有显著意义的结果;但ＡｐＥｎ分析则可敏感地检测出有氧锻炼关联的心率动力学细微变化,且初步揭示ΔＡｐＥｎ与立位耐力变化（ΔＤＮＰ）间显著相关。以上对阐明有氧锻炼对心率动力学调节的影响以及改进ＨＲＶ信号分析工作均有一定意义。     

迷走神经兴奋性对HRV的影响及其机制的初步分析

实验在氯醛糖加氨基甲酸乙酯麻醉的新西兰兔上进行。记录血压,心率,心电图和心率变异性频谱分析。电刺激减压神经,疑核和右侧迷走神经外周端,均引起心率和血压下降,总变异性,低频成分,高频成分,ＬＦ／ＨＦ比值和极代频成分增大。静脉注射阿托品可使上述反应显著减小,而静脉注射心得安仅可阻断ＤＮ和ＮＡ所致ＬＦ的增大。     

兔心迷走神经传出放电的活动特征

兔心迷走神经传出放电有三种类型:1.与后膈神经传出发放同步的节律性放电。这种节律性发放包含两个时相,第一时相大致与膈神经传出放电同时起止,第二时相在膈神经传出发放后期或发放终止时出现。2.持续性放电,出现在上述节律性放电的间歇期。3.偶然出现的高幅高频暴发放电。这种放电出现时,膈神经传出放电即受到明显的压抑。开放预先夹闭的颈总动脉使心迷走神经传出放电增强。窒息、静脉注射肾上腺素使心迷走神经传出放电增强,心率减慢;扩张肺、过度通气、吸入亚硝酸异戊酯使心迷走神经传出放电减少,心率增快。     

不同年龄健康被试者心率变异性的谱分析研究

对不同年龄健康男性被试者卧、立位条件下,心率变异性（ｈｅａｒｔ ｒａｔｅ ｖａｒｉａｂｉｌｉｔｙ,ＨＲＶ）谱高、低频成分随年龄变化的规律进行研究。结果表明：虽然各年龄组间卧、立位时的静息平均心率并无显著差别,但ＨＲＶ却随年龄的增长而明显降低,青年组ＨＲＶ谱高、低频谱峰功率的显著高于中年组、中老年组及老年组（Ｐ〈０．０５或Ｐ〈０．０１）;ＨＲＶ谱低频谱功率、高频谱功率及总功率均随年龄增长呈指数衰减规     

基于复杂度的心率变异性分析研究进展

心率变异性（HRV）是当前心电图分析的一个前沿热点,它反映了交感神经和副交感神经对心血管系统的综合调节作用,是评价心血管系统功能的重要指标。随着非线性动力学和复杂性科学的发展,HRV信号被普遍认为是混沌或含有混沌成分的信号。复杂度是用来表征一个心率非线性动力学系统复杂程度的量度,以其简单快速的优点引起了众多研究者的兴趣,并广泛应用于心率变异性分析。本文综述了国内外复杂度算法的研究进展及基于复杂度的心率变异性分析的临床应用及前景。     

蝮蛇抗栓酶伍用刺五加冠心病心率变异性的影响

目的 探讨蝮蛇抗栓酶伍用刺五加对冠心病心率异性的影响。方法 观察蝮蛇抗栓酶伍用刺五加对冠心病为异性的影响，并与对照组对比。结果 治疗组ＳＤＮＮ、ＨＦ、ＬＦ／ＨＦ改变较对照组有显著差异性（Ｐ〈０．０１）。结论 该方法能显著提高冠心病患者的心率变异性，对冠心病源性猝死的预防有着重要意义。     

化学反射性活动对心率变异性的影响

心率变异性 (ｈｅａｒｔｒａｔｅｖａｒｉａｂｉｌｉｔｙ ,ＨＲＶ)正在被临床广泛用于作为疾病的诊断、治疗和愈后的指标。目前认为 ,在ＨＲＶ频谱分析图中 ,高频波段 (ｈｉｇｈｆｒｅｑｕｅｎｃｙ ,ＨＦ)与呼吸活动有关 ,由迷走神经单独介导。低频波段 (ｌｏｗｆｒｅｑｕｅｎｃｙ ,ＬＦ)受交感神经和副交感神经活动的双重调节。而极低频波段 (ｖｅｒｙｌｏｗｆｒｅｑｕｅｎｃｙＶＬＦ)除受自主神经的调节外 ,还受温度、外周血管运动活动以及神经激素的影响。近来有报道在慢性心衰患者中 ,ＶＬＦ与外周化学感受器的敏感性增加有关。本实验通…     

心率与血压的变异性：分析方法,生理意义及其应用

本文回顾了关心回顾变异性及血压变异性的最新进展。在分析方法方面介绍了单一生理变量多变量系统的线性分析技术及其主要结果。对ＨＲＶ／ＢＰＶ谱的生理意义及其应用问题,也进行了回顾了评述。     

The upper esophageal sphincter in the cat: the role of central innervation assessed by transient vagal blockade

Studies were performed on four cats to assess the role of extrinsic innervation via the cervical nerve trunks in the control of upper esophageal sphincter function. Transient vagal nerve blockade was accomplished by cooling the cervical vagosympathetic nerve trunks previously isolated in skin loops on each side of the neck. Upper esophageal sphincter pressure was measured using a multilumen oval manometry tube and a rapid pull-through technique. The upper esophageal sphincter response to cervical intraesophageal balloon distention and acid perfusion was assessed. The feline upper esophageal sphincter has a distinct asymmetric pressure profile, whereby anterior pressure greater than posterior pressure greater than left pressure greater than right pressure. Bilateral vagal nerve blockade lowered the mean upper esophageal sphincter pressure from 18.5 +/- 1.5 to 12.0 +/- 2.8 mmHg (1 mmHg = 133.3 Pa) (p less than 0.001), with a significant reduction in pressure in all four quadrants. Intraesophageal balloon distention and acid perfusion both produced a significant increase in upper esophageal sphincter pressure. Bilateral vagal nerve blockade completely abolished the response of the upper esophageal sphincter to balloon distention and acid perfusion. We conclude that normal upper esophageal sphincter tone in the cat is partially mediated by excitatory neural input via the cervical nerve trunks, presumably via the recurrent laryngeal nerves; and cervical intraesophageal balloon distention and acid perfusion produce reflex contraction of the upper esophageal sphincter, which is dependent on neural pathways via the cervical vagal nerve trunks, but the relative contribution of afferent and efferent pathways remains unknown.     

Oesophageal peristalsis in the cat: the role of central innervation assessed by transient vagal blockade

Studies were performed on five cats to assess the role of extrinsic vagal innervation in the control of peristalsis in the smooth muscle oesophagus. Transient vagal nerve blockade was accomplished by cooling the cervical vagosympathetic nerve trunks previously isolated in skin loops on each side of the neck. Peristalsis throughout the body of the oesophagus was monitored using a continuously perfused multilumen manometry tube. Striated and smooth muscle portions of the esophagus were delineated by abolishing smooth muscle activity with atropine. Secondary peristalsis was assessed by intra-oesophageal balloon distension studies. The threshold volume for balloon-induced secondary peristalsis was lower in the smooth muscle oesophagus. Unilateral vagal blockade reduced the incidence of primary and secondary peristalsis in the striated muscle oesophagus but not in the smooth muscle oesophagus. Bilateral vagal nerve blockade abolished primary swallow-induced peristalsis and secondary peristalsis in both the smooth and striated muscle cat oesophagus. Administration of cholinergic agents or adrenergic blocking agents failed to restore secondary peristalsis in the smooth muscle oesophagus during vagal cooling. We conclude that connections to the central nervous system via the vagal nerve trunks are required for normal secondary as well as primary peristalsis in both the smooth and striated muscle portions of the cat oesophagus.     

Adrenergic innervation of the dorsal vagal motor nucleus: possible involvement in inhibitory control of gastric acid and pancreatic insulin secretion

Summary Morphological and physiological approaches were used to investigate the possible role of an adrenergic innervation of the dorsal vagal complex in the control of basal gastric acid and pancreatic insulin secretion in the rat. The use of retrograde-tracing methods with injections of True Blue or of wheat-germ agglutinin into the stomach or pancreas first confirmed that most vagal preganglionic neurons innervating these two viscera are localized in the dorsal motor nucleus of the vagus, a number of them connected to both viscera. Light- and electron-microscopic investigation of the organization of adrenergic neuronal structures immunoreactive to phenylethanolamine-N-methyltransferase within this medullary nucleus further revealed: (i) that adrenergic axons establish profuse synaptic connections of the symmetrical type with perikarya and dendrites of this nucleus, and (ii) that several of these adrenergic fibers are connected with retrogradely labeled neurons innervating the stomach and/or pancreas. Lastly, measurements of basal gastric acid output and plasma insulin clearly indicated that both visceral secretions are rapidly and conspicuously decreased by local infusion of 2 nM adrenaline within the dorsal vagal complex. Taken together, these data strongly suggest that the adrenergic innervation of the dorsal medulla oblongata is involved in direct synaptic inhibition of the parasympathetic preganglionic neurons of the vagus that control secretion of gastric acid and pancreatic insulin.     

Gastric and duodenal motility in the cat: the role of central innervation assessed by transient vagal blockade

Experiments were performed on four cats to characterize fasting gastric and small bowel motility and to assess the role of extrinsic vagal innervation in the control of that motor activity. A multilumen manometry tube was positioned to record pressure changes from the proximal small bowel and stomach. Transient vagal nerve blockade was accomplished by cooling the cervical vagosympathetic nerve trunks, previously isolated in skin loops on each side of the neck. Two characteristic patterns of basal activity were documented in the stomach: (i) regular phasic contractions of variable amplitude in the body of the stomach; and (ii) infrequent, irregular contractions of high amplitude in the distal antrum. In the duodenum, two predominant activity patterns were noted: (i) periods of continuous irregular activity; and (ii) irregular clusters of contractions separated by quiescent intervals. No typical migrating motor complex activity was seen in the basal gastric or small bowel recordings. Bilateral vagal blockade did not consistently change the general pattern of gastric or small bowel activity, but did appear to reduce gastric contractile activity, as measured by motility indices. We conclude that extrinsic vagal innervation does not play a major role in the control of fasting feline gastric and duodenal motility.     

Chromatin matrix activity in hepatocyte nuclei after disturbance of the hepatic vagal innervation

The level of matrix activity of extranucleolar and nucleolar chromatin in hepatocytes of white noninbred rats has been studied in dynamics after disturbance of the vagal innervation. In order to estimate the labelling intensity of nuclear structures, the histoautoradiographic method is used. After bilateral subdiaphragmal vagotomy at early stages (1-2 weeks) the level of the nucleoplasm and nucleolus increases essentially, and by the 30th day a tendency to its normalization is noted. A conclusion is made that the peripheral nervous system influences the intensity of metabolic processes in the nucleus.