前庭功能的中枢组胺能神经调制

组胺能药物已经长期用于治疗人类的平衡紊乱,但对于它们在前庭系统中作用的机制还缺乏了解。在本文中,我们综述了关于脑内（特别是脑干前庭核中）的组胺能神经传递,以及组胺在脑可塑性——“前庭代偿”（一种单侧外周前庭损伤之后发生的行为学恢复）中作用的新近文献。我们在综述组胺能类药物促进前庭代偿证据的同时,也讨论了这类药物临床应用的可能性。     

Adaptational Modifications of the Vestibular Postural Response in Humans under Conditions of Horizontal Visual Reversal

In healthy volunteers, we recorded stabilograms and studied postural responses evoked by galvanic stimulation of the labyrinth (binaurally applied 1-mA current, 4 sec) with the subjects' eyes open and closed and under conditions of reversed visual perception. Horizontal reversal of the visual space was provided by using spectacles with the Dove's prisms. In series consisting of 10 sequential tests with eyes open, we observed a gradual drop in the response amplitude, while there were practically no changes in the maximum velocity of the displacement. Postural responses with eyes closed were considerably greater than those with eyes open, but their amplitude and velocity demonstrated no changes with sequential tests. Under conditions of reversal of the visual perception, both the amplitude and maximum velocity of the postural responses decreased with successive testing. Under the above conditions, at the beginning of a test series responses to vestibular stimulation were greater than those with eyes closed, but in repeated tests they decreased and attained the same magnitude as in the tests with eyes closed. Therefore, the effect of short-term adaptation to visual reversal on the system controlling vertical posture resulted in simple rejection of the information coming via the visual input. In another experimental mode, we studied the adaptation effects at longer (3 h long) visual reversal. Postural responses to galvanic stimulation of the labyrinth (monaurally applied, 2-mA current, 4 sec) were tested with 1-h-long intervals; tests with visual reversal and with eyes closed were made in a random order with each other. A 3-h-long interval with the prismatic spectacles on did not modify the amplitude and velocity of the vestibular postural responses when the tests were made with the eyes closed. When the tests were performed with the eyes open, but in the inverting spectacles, postural responses significantly decreased (by about 50-60%) to the 2nd and 3rd h of the experiment. Such selective suppression of the vestibular input under conditions of visual reversal can be interpreted as a result of adaptational transformation of the visual-vestibular relation directed toward minimization of the visual-vestibular conflict.     

单侧迷路破坏后大鼠前庭神经内侧核区氨基酸含量的变化

本实验用脑部微量透析法和高效液相色谱法观察单侧迷路破坏(unilateral labyrinthectomy,经利多卡因或对氨基苯胂酸盐预处理以阻断单侧外周前庭器官)后大鼠同侧及对侧前庭神经内侧核(medial vestibular nucleus,MVN)区部分氨基酸(天冬氨酸、谷氨酸、谷氨酰胺、甘氨酸、牛磺酸和丙氨酸)含量的变化,以了解前庭代偿的部分神经化学机制.实验观察到,对照组大鼠MVN区天冬氨酸、谷氨酸、谷氨酰胺、甘氨酸、牛磺酸和丙氨酸浓度分别为(6.15±0.59),(18.13±1.21),(33.73±1.67),(9.26±0.65),(9.56±0.77)和(10.07±0.83)pmol/8 μL透析样本.左侧中耳内灌注2%利多卡因后10 min,同侧MVN区天冬氨酸、谷氨酸含量立即减少(P＜0.05),牛磺酸含量增加(P＜0.05);对侧MVN区谷氨酸含量立即增加(P＜0.05),甘氨酸和丙氨酸含量减少;双侧核团间谷氨酸、甘氨酸和丙氨酸含量失衡.而用对氨基苯胂酸盐永久阻断单侧前庭器官2周后,同侧MVN区谷氨酸和丙氨酸含量减少,谷氨酰胺含量增高;对侧MVN区谷氨酸含量也减少;同侧MVN区谷氨酰胺含量明显高于对侧MVN区.结果提示,单侧迷路破坏后双侧MVN区氨基酸含量立即失去平衡,随着前庭代偿的进展,此差异减少,但是在前庭代偿后却出现双侧前庭核区谷氨酰氨的含量失衡,说明在前庭代偿过程中氨基酸含量变化起着重要作用.     

Dependence of the Magnitude of Postural Reactions in Humans on the Strength of Unilateral Galvanic Anodal and Cathodal Vestibular Stimulations

In 13 healthy volunteers, we recorded stabilographic postural reactions (side inclinations of the body) to unilateral galvanic vestibular stimulation (GVS) by rectangular current pulses (4 sec long, 2, 3, 4, 5, or 6 mA). For the cathodal GVS, the dependence of the magnitude of reaction was linear within this range. The corresponding dependence for the anodal GVS was close to linear at small currents, but the increment of the magnitude became smaller with further increase in the stimulation intensity, and a plateau was formed. A significant divergence between the two curves was observed with stimulation currents 4 mA and higher. This difference can be explained considering modern concepts on the mechanism of GVS-induced effects (an increase or a decrease in the level of tonic impulsation in fibers of the vestibular nerve under the influence of polarization). Anodal GVS continues to suppress tonic activity up to the moment where all GVS-sensitive vestibular afferents stop to generate impulses; a further increase in the intensity of hyperpolarizing current is not accompanied by a decrease in the activity in the vestibular nerve and, consequently, by an increase in the magnitude of postural reactions. The tested approach can be used for qualitative estimation of the vestibular tone in humans. Neirofiziologiya/Neurophysiology, Vol. 37, No. 2, pp. 169–176, March–April, 2005.     

Intraobserver reliability of posturography in patients with vestibular neuritis

The aim of the study was to establish the intraobserver reliability of a posturographic method in patients (n?=?34) with vestibular neuritis. Intraclass correlation coefficients (relative reliability) for all parameters and test positions (ALL_mean) ranged from 0.71 (95% CI: 0.41–0.85) to 0.92 (95% CI: 0.84–0.96). Absolute reliability (coefficient of variation) ranged between 3.1% (95% CI: 2.60–8.67) and 42.3% (95% CI: 40.7–74.5). Reliability of single test positions is much lower. The posturographic system showed good relative and satisfactory absolute intraobserver reliability for ALL_mean.     

Early postnatal maturation in vestibulospinal pathways involved in neck and forelimb motor control

To assess the organization and functional development of vestibulospinal inputs to cervical motoneurons (MNs), we have used electrophysiology (ventral root and electromyographic [EMG] recording), calcium imaging, trans‐synaptic rabies virus (RV) and conventional retrograde tracing and immunohistochemistry in the neonatal mouse. By stimulating the VIIIth nerve electrically while recording synaptically mediated calcium responses in MNs, we characterized the inputs from the three vestibulospinal tracts, the separate ipsilateral and contralateral medial vestibulospinal tracts (iMVST/cMVST) and the lateral vestibulospinal tract (LVST), to MNs in the medial and lateral motor columns (MMC and LMC) of cervical segments. We found that ipsilateral inputs from the iMVST and LVST were differentially distributed to the MMC and LMC in the different segments, and that all contralateral inputs to MMC and LMC MNs in each segment derive from the cMVST. Using trans‐synaptic RV retrograde tracing as well as pharmacological manipulation of VIIIth nerve‐elicited synaptic responses, we found that a substantial proportion of inputs to both neck and forelimb extensor MNs was mediated monosynaptically, but that polysynaptic inputs were also significant. By recording EMG responses evoked by natural stimulation of the vestibular apparatus, we found that vestibular‐mediated motor output to the neck and forelimb musculature became more robust during the first 10 postnatal days, concurrently with a decrease in the latency of MN discharge evoked by VIIIth nerve electrical stimulation. Together, these results provide insight into the complexity of vestibulospinal connectivity in the cervical spinal cord and a cogent demonstration of the functional maturation that vestibulospinal connections undergo postnatally. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1061–1077, 2016     

Brief communication: Investigation of the semicircular canal variation in the Krapina Neandertals

Previous studies comparing bony labyrinth morphology in geographically‐dispersed samples of Neandertals and modern Homo sapiens (H. sapiens) showed that Neandertals generally have smaller semicircular canals than modern H. sapiens (Hublin et al., 1996 ; Spoor et al., 2003 ; Glantz et al., 2008 ). Here we analyze the morphology of a single group of Neandertal specimens from one locale, the Krapina site, to determine the intraspecific variation in Neandertal semicircular canal sizes. Dimensions of the semicircular canals were collected from computed tomography scans of nine temporal bones. With the rare exception, the dimensions of the semicircular canals in the Krapina sample are similar to those previously reported across a geographically‐dispersed sample of Neandertals, further supporting previous studies that suggest low levels of variation in the semicircular canals for Neandertals. Am J Phys Anthropol 154:302–306, 2014. © 2014 Wiley Periodicals, Inc.     

超重状态出生大鼠转入正常重力状态后行为和Fos表达的改变

本工作观察了在超重（2G）环境中出生、生态4个月后返回正常（1G）环境的Long-Evans大鼠运动行为的改变和恢复,以及相关脑区Fos表达水平的变化,并与旋转刺激（重力变化的对照组）和去前庭传入大鼠相比较,结果表明：重力的变化导致实验大鼠表态和运行行为模式改变,伸肌张力增加,运动平衡、游泳定向和空中翻正的能力降低,对1G环境再适应的时程因行为的不同而异,其中游泳定向能力的恢复时间最长,长于1个月,旋转只对运动行为有短暂的影响。Fos表达被认为是揭示参与应答感觉刺激而功能活跃脑区的有用工具。结果显示,正常和毁迷路的对照大鼠的Fos呈低水平表达,减重刺激使上、下丘脑和围导水管灰质、中缝背核及孤束核的水平显著上调,相反,下橄榄、蓝斑和前庭核团的Fos水平没有明显改变,表明脑干对不同重力刺激存在不同的调控神经途径。     

Balance Control Mediated by Vestibular Circuits Directing Limb Extension or Antagonist Muscle Co-activation

1. Download high-res image (162KB)
2. Download full-size image

     

Evolution of locomotion in Anthropoidea: the semicircular canal evidence

Our understanding of locomotor evolution in anthropoid primates has been limited to those taxa for which good postcranial fossil material and appropriate modern analogues are available. We report the results of an analysis of semicircular canal size variation in 16 fossil anthropoid species dating from the Late Eocene to the Late Miocene, and use these data to reconstruct evolutionary changes in locomotor adaptations in anthropoid primates over the last 35 Ma. Phylogenetically informed regression analyses of semicircular canal size reveal three important aspects of anthropoid locomotor evolution: (i) the earliest anthropoid primates engaged in relatively slow locomotor behaviours, suggesting that this was the basal anthropoid pattern; (ii) platyrrhines from the Miocene of South America were relatively agile compared with earlier anthropoids; and (iii) while the last common ancestor of cercopithecoids and hominoids likely was relatively slow like earlier stem catarrhines, the results suggest that the basal crown catarrhine may have been a relatively agile animal. The latter scenario would indicate that hominoids of the later Miocene secondarily derived their relatively slow locomotor repertoires.     

Effect of Long-Lasting Vibration on the Impulse Activity of Neurons of the Inferior Vestibular Nucleus

We analyzed the impulse background activity (BA) of neurons of the inferior vestibular nucleus (IVN) of rats during exposure to long-lasting vibration (daily 2-h-long sessions). It was demonstrated that 5 days after the beginning of vibration stimulation, practically all main characteristics of the BA of IVN neurons changed significantly. In the studied neuronal group, 10 days after the vibration onset we observed an increase in the mean frequency of the BA and shifts in many statistical parameters of the BA, while after 15 days of vibration only significant modifications of dynamic characteristics of the BA of IVN neurons were manifested.Neirofiziologiya/Neurophysiology, Vol. 37, No. 1, pp. 32–38, January–February, 2005.     

Modifications of Neuronal Activity in the Medial Vestibular Nucleus during Long-Term Vibration

The impulse background activity (BA) of neurons of the rat medial vestibular nucleus (MVN) was subjected to computer analysis, and its modifications related to long-term vibration were studied. It was shown that following 5 days of 2-h-long vibration sessions, statistically significant changes in some basic characteristics of BA generated by MVN neurons were observed. More than a twofold increase in the mean BA frequency and substantial shifts practically of all statistical BA parameters were found after 10 days of vibration. Following a 15-day-long vibration, MVN neurons showed a clear-cut tendency to restore control values of the BA indices, which probably was related to adaptation processes.     

前庭电刺激联合前庭康复治疗周围性眩晕的疗效观察

目的：观察前庭电刺激联合前庭康复治疗周围性眩晕的疗效。方法：在常规药物治疗基础上将2008年5月．2012年5月我科眩晕门诊收治的226例诊断明确的单侧前庭周围性眩晕患者随机分成两组：前庭康复组和前庭康复＋前庭电刺激组。前庭康复组行常规前庭康复治疗,前庭康复＋前庭电刺激组在药物治疗及前庭康复基础上加用前庭电刺激,即在双侧乳突采取双极直流电刺激,每次15-20分钟,每天2次,共6周。治疗前及治疗后第2、4、6周行BBS评分及计时平衡试验时间测定以评判和比较两组的疗效。结果：两组患者治疗后第2、4、6周BBS评分及计时平衡试验时间较治疗前均明显增加（P〈0．05）,且B组各时点BBS评分及计时平衡试验时间均明显高于A组（P〈0．05）。结论：前庭电刺激联合前庭康复是较单纯前庭康复治疗前庭周围性眩晕更加有效的方法,其简单、无创、值得推广。     

Studies of somatostatin-induced barrel rotation in rats

Somatostatin (SRIF) has been reported to induce abnormalities of motor behavior in rats when injected intraventricularly. Following an injection, non-lesioned rats develop unilateral extension of the limbs, a twist about the long axis, and repeated lateral rolling, called "barrel rotation". It has not been clear whether this behavior is due to a pharmacologic action of SRIF, such as an effect of SRIF on systems of motor control. Prior reports observed the response only at high doses of SRIF, and found no dose-response relationship for it. We have investigated whether this response is due to a pharmacologic effect of SRIF. We have also studied where SRIF acts, when injected intraventricularly, to induce this response. We have found that SRIF-induced rotation increases linearly with doses up to 10 micrograms and thereafter declines. Biologically inactive analogues of SRIF did not induce barrel rotation. Dose-response studies of intraventricular and intracerebral microinjections indicated that SRIF acts at the vestibular nuclear complex (VNC) to induce rotation. At VNC, 0.25 micrograms SRIF produced postural abnormalities. We conclude that barrel rotation is due to a pharmacologic action of SRIF, and that SRIF does act upon a system of motor control, the VNC, to induce this response.     

急性低血压对前庭神经内侧核区谷氨酸和牛磺酸含量的影响

本实验用脑部微量透析法和高效液相色谱法观察急性失血诱发大鼠低血压时前庭神经内侧核(medial vestibular nucleus,MVN)内氨基酸类神经递质谷氨酸(glutamate,Glu)和牛磺酸(tautine,Tau)含量的变化,以了解MVN内这些氨基酸类递质是否参与血压的调节。实验观察到,正常血压大鼠MVN内Glu和Tau浓度在透析探针植入90 min后趋于稳定,此时 Glu的平均含量为(18．96±0．27)pmol／8 μl透析液,Tau的平均含量为(7．73±0．05)pmol/8μl透析液。动脉抽血1．5 ml诱发急性低血压时,同侧MVN区Glu含量增加(P<0．05),Tau含量减少(P<0．05)。用利多卡因(lidocaine)短时阻断前庭传入及用化学方法永久破坏单侧前庭器官后,动脉抽血1.5 ml使血压降低30％,同侧MVN内氨基酸类神经递质无明显改变。结果提示,急性失血引起的低血压可通过前庭器官影响MVN的活动,该区内氨基酸类递质可能参与这一活动的调节。     

Visual learning and memory of Drosophila melanogaster wild type CS and the mutants dunce1, amnesiac, turnip and rutabaga

Dunce¹, amnesiac, turnip and rutabaga, mutants of Drosophila melanogaster deficient in olfactory learning and/or memory, were tested for visual learning ability and memory. All these mutants are able to learn conditioned visual information, but not as well as the corresponding wildtype CS. Memory of all four mutants is reduced during the first 30 min after training, but indistinguishable from that of the wildtype two hours after conditioning.