Electroacupuncture reduces the evoked responses of the spinal dorsal horn neurons in ankle-sprained rats

Acupuncture is shown to be effective in producing analgesia in ankle sprain pain in humans and animals. To examine the underlying mechanisms of the acupuncture-induced analgesia, the effects of electroacupuncture (EA) on weight-bearing forces (WBR) of the affected foot and dorsal horn neuron activities were examined in a rat model of ankle sprain. Ankle sprain was induced manually by overextending ligaments of the left ankle in the rat. Dorsal horn neuron responses to ankle movements or compression were recorded from the lumbar spinal cord using an in vivo extracellular single unit recording setup 1 day after ankle sprain. EA was applied to the SI-6 acupoint on the right forelimb (contralateral to the sprained ankle) by trains of electrical pulses (10 Hz, 1-ms pulse width, 2-mA intensity) for 30 min. After EA, WBR of the sprained foot significantly recovered and dorsal horn neuron activities were significantly suppressed in ankle-sprained rats. However, EA produced no effect in normal rats. The inhibitory effect of EA on hyperactivities of dorsal horn neurons of ankle-sprained rats was blocked by the α-adrenoceptor antagonist phentolamine (5 mg/kg ip) but not by the opioid receptor antagonist naltrexone (10 mg/kg ip). These data suggest that EA-induced analgesia in ankle sprain pain is mediated mainly by suppressing dorsal horn neuron activities through α-adrenergic descending inhibitory systems at the spinal level.     

Survival and phenotypic characteristics of axotomized neurons in spinal ganglia

Trauma to the peripheral processes of sensory neurons of different subpopulations was followed by indirect immunohistochemical analysis of the expression of Bcl-X_L and Bax, which are, respectively, antiapoptotic and proapoptotic proteins of the Bcl-2 family, and also of the cytokine interleukin-1, with the aim of identifying the roles of these substances in controlling apoptosis. The survival abilities of these neurons after central and peripheral axotomy were compared by studying the expression of the high molecular weight component of the neurofilament triplet NF200 and isolectin B₄ (IB₄). By day 30 after central axotomy, there were no changes in the total numbers of neurons in ganglia L_IV-L_V in rats, though there were significant reductions in the numbers of NF200⁺ neurons. In spinal ganglion L_V of mice, the proapoptotic protein was detected in the nuclei of 46% of small neurons, which account for 20% of all neurons in the ganglion. By day 30 after nerve compression, Bax was expressed in the nuclei of 30% of neurons and the cytoplasm of 20% of neurons. In intact animals, the antiapoptotic protein Bcl-X_L was seen in the cytoplasm of 30% of small neurons, as well as in satellite cells surrounding large and intermediate neurons. By day 30 after nerve trauma, Bcl-X_L was not expressed in spinal ganglion L_V. Interleukin-1 was present in the cytoplasm of 17% of neurons belonging to the subpopulations of large and intermediate neurons. By day 30 after nerve compression, interleukin-1⁺ neurons were not identified.Translated from Morfologiya, Vol. 125, No. 3, pp. 45–49, May–June, 2004.     

利福平对鱼藤酮处理的大鼠多巴胺神经元的保护作用

目的：观察利福平对鱼藤酮诱导帕金森病大鼠模型多巴胺神经元的保护作用以及对α-突触核蛋白形成和聚集的抑制作用。方法: 持续3周给SD大鼠背部皮下注射鱼藤酮（1.5 mg·kg^-1·d^-1）以诱导其黑质多巴胺神经元丢失的同时，应用利福平（30 mg·kg^-1·d^-1）灌胃给药，并通过对大鼠进行行为学、黑质病理学、TH和α-突触核蛋白的免疫活性以及蛋白量的表达情况等方面的检测以证明利福平对帕金森病动物模型多巴胺神经元具有保护作用，对α-突触核蛋白的形成和聚集具有抑制作用。结果: 低剂量长期背部皮下注射鱼藤酮可诱导SD大鼠出现行为学、黑质病理学、TH及α-突触核蛋白的免疫活性和蛋白量的表达情况的改变，而应用利福平灌胃后这些变化均显著减少。结论: 利福平对鱼藤酮帕金森病大鼠模型的多巴胺神经元具有保护作用，此作用与其对模型中α-突触核蛋白的形成和聚集的抑制作用密切相关。     

Postnatal rat nigrostriatal dopaminergic neurons exhibit five types of potassium conductances

1. We have investigated the electrical properties of neurons acutely dissociated from the substantia nigra zona compacta (SNZC) of the postnatal rat with whole cell patch-clamp recordings. Retrogradely labeled nigrostriatal neurons were identified with the use of rhodamine-labeled fluorescent latex microspheres. Over 90% of the rhodamine-labeled neurons in the SNZC demonstrated formaldehyde/glutaraldehyde-induced catecholamine fluorescence, indicating that they were dopaminergic (DA) neurons. 2. DA neurons had 15-20 microns ovoid or fusiform-shaped cell bodies with 2-3 thick proximal processes. Labeled neurons generated spontaneous action-potential activity in both regular and irregular patterns. These cells exhibited input resistances of 300-600 M omega and action-potential amplitudes of 60-80 mV. Locally applied dopamine inhibited the spontaneous activity of these neurons by hyperpolarizing the cells. 3. Outward currents were examined with voltage-clamp recordings using a tetrodotoxin (TTX)-containing medium. In all DA cells, depolarizing voltage commands activated several components of outward current depending on the holding potential of the cell. When cells were held at -40 mV (or more positive), voltage steps activated a sustained outward current. If the membrane potential was held more negative than -50 mV, a rapidly activating and inactivating component of outward current response could also be detected. 4. From a hyperpolarized holding potential (-90 mV) the transient outward current activated with depolarizing commands to -55 mV, peaking within 5 ms. The current inactivated with a monoexponential time constant of 53 +/- 4 (SE) ms. At more positive holding potentials (-40 mV) the steady-state inactivation of the current could be removed by applying a conditioning hyperpolarizing prepulse. In response to a fixed depolarizing voltage step, half-maximal inactivation occurred at about -65 mV. The transient current was blocked by 4-aminopyridine (4-AP). 5. The sustained outward currents were isolated by holding the cells at -40 mV. Two components of sustained outward current were distinguished by their sensitivity to the calcium channel blockers Co2+ (5 mM) and/or Cd2+ (200 microM). The current remaining in the presence of Co2+/Cd2+ was activated by depolarizing voltage commands more positive than -40 mV.(ABSTRACT TRUNCATED AT 400 WORDS)     

Electrophysiological responses of human spinal neurons in culture

Cell cultures were prepared from human fetal spinal cord and maintained in vitro for 30-100 days. Neurons were identified electrophysiologically by their ability to develop action potentials in response to intracellular depolarizing current pulses and in sister cultures by immunohistochemical and electron microscopic techniques. Extracellular applications of gamma-aminobutyric acid, glycine or histamine evoked hyperpolarizations which were associated with increases in membrane conductance. These data and the ultrastructural demonstrations of synapses suggest a functional differentiation of neurons in these cultures.     

Morphofunctional characteristics of neurons in the spinal ganglia of the dog in the post-distraction period

The aims of the present work were to study the morphofunctional state of neurons in the spinal ganglia and to perform a comparative analysis of changes in neuron-glial relationships after lengthening of the hindlimb of mongrel dogs by 14–16% of initial at different rates. Longitudinal serial sections of thickness 5 μm of the L6, L7, and S1 ganglia (n = 36) stained with thionine and cresyl violet by the Nissl method and hallocyanine and chromic alum by the Einarson method were examined. Reversible transformations of the structure of some neurons were seen at 45–48 days, these consisting of hyperchromia of the cytoplasm and nucleus, peripheral chromatolysis, displacement of the nucleolus, and increases in the quantities of perineuronal and interneuronal gliocytes. Changes were most marked in the ganglia on the side of limb lengthening at a rate of 3 mm/day, while the smallest changes were seen on the side contralateral to limb lengthening at a rate of 1 mm/day. __________ Translated from Morfologiya, Vol. 127, No. 2, pp. 44–47, March–April, 2005.     

不同时程吗啡依赖对大鼠中脑腹侧被盖区多巴胺能神经元的影响

目的:观察不同时程吗啡依赖对大鼠中脑腹侧被盖区(ventral tegmental area,VTA)多巴胺能神经元的影响。方法:建立吗啡慢性依赖大鼠模型,石蜡包埋组织连续切片,免疫组织化学染色观察多巴胺能神经元特异性标记物酪氨酸羟化酶(tyrosine hydroxylase,TH)的表达变化。结果:TH免疫组化结果显示随着吗啡依赖时间的延长VTA区内TH阳性细胞逐渐减少,吗啡依赖6周组阳性细胞减少明显。结论:较长时程吗啡依赖大鼠VTA多巴胺能神经元损伤明显。     

Characteristics of the responses of various spinal neurons to direct stimulation

Summary Responses of various units in the cat's spinal cord to direct stimulation were studied by means of double-barreled intracellular microelectrodes. Three main types of units were found, corresponding to the three types of single-unit responses during reflex stimulation.(Presented by Active Member AMN SSSR V. N. Chernigovskii) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 50, No. 9, pp. 8–11, September, 1960     

Localization of NADPH-diaphorase containing neurons in the spinal dorsal horn and spinal sensory ganglia of the turtle Chrysemys d’orbigny

 NADPH-diaphorase positive (NDP) neurons and nerve fibers were found in the spinal dorsal horn (DH) and sensory ganglia of the turtle Chrysemys d’orbigny. Three well-defined types of NDP neurons were found in the DH: (a) elongated nerve cells with two radially arranged dendritic branches, (b) neurons with rostro-caudal dendritic branches, (c) bitufted neurons with two, practically symmetric branches that project to the ipsilateral and contralateral dorsal horns. A combination of the techniques that reveal NADPH-diaphorase activity with the horseradish peroxidase transganglionic labeling of the dorsal root collaterals, suggested that NDP neurons of the DH are second-order cells of the spinal sensory pathway. NDP neurons were also found in the spinal sensory ganglia at all metameric levels. Our findings indicate that the DH of turtles, like that of mammals, contains both the enzymatic machinery and the neural connections required to postulate the participation of nitric oxide in ”plastic phenomena” such as hyperalgesia and central sensitization. Two other alternatives or complementary hypotheses are discussed: (a) NDP neurons in the DH and sensory ganglia may represent specific cell populations involved in the processing of sensory visceral information; (b) NADPH-diaphorase reactivity may indicate sustained levels of neuronal activity. Received: 12 February 1996 / Accepted: 2 August 1996     

Effect of space flight on composition of soluble proteins of the spinal cord and spinal ganglia of rats

The content of individual protein fractions extracted from the spinal cord, at the level of the lumbar enlargement, and the spinal ganglia of rats consecutively with distilled water, 0.85% NaCl solution, and 0.1 N NaOH solution was investigated. A significant decrease in the content of water-soluble proteins was found in the white and gray matter of the spinal cord 12 h after space flight. The content of salt-soluble and alkali-soluble proteins in the structures of the spinal cord and spinal ganglia per milligram wet weight of tissue was not significantly altered. A significant increase in the content of water-soluble proteins compared with the control was found in the gray matter of the spinal cord 25 days after space flight. The content of water-soluble proteins in the white matter of the spinal cord was increased to the control level. A significant increase also was observed in the content of alkali-soluble proteins in the spinal ganglia.Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 8, pp. 168–171, August, 1977.     

The organization of 10 nm filaments and microtubules in embryonic neurons from spinal ganglia

Summary The distribution of tubulin and 10 nm filament protein: vimentin and the 70 K neurofilament component, was investigated in cultures of dorsal root ganglion cells by indirect immunofluorescence using antisera specific for these proteins. The neuronal cell bodies and the neurites in these cultures were brightly stained. Fibres stained with both tubulin and 10 nm filament antibodies were visible at branch points, whereas only microtubules extended into growth cones, including those that were in the process of bifurcation. Differences in the arrangement of microtubules and 10 nm filaments were also detected during colcemid-induced neurite retraction. After complete retraction, perinuclear coils of 10 nm filaments were found in the cell bodies whereas only very weak diffuse tubulin staining was visible. When regrowth commenced on removal of colcemid, microtubule organizing centres were visible in the cell bodies and were then rapidly obscured by bright staining which later extended into the neurite stump. Similarly, the 10 nm coils were replaced by fibrous staining which also projected into the growing neurite. These observations suggest that the extension of microtubules and 10 nm filaments is both co-ordinated and sequential, with microtubules having a dynamic role in growth and 10 nm filaments stabilizing the pattern of growth thereafter.     

桩蛋白在两型星形胶质细胞及神经元中的差异表达

目的:观察桩蛋白在大鼠两型星形胶质细胞及神经元中的差异表达情况。方法:通过细胞培养并结合免疫荧光和RT-PCR方法,观察了桩蛋白的mRNA及蛋白在大鼠两型星形胶质细胞T1A和T2A以及神经元中的表达。结果:RT-PCR显示体外培养的T1A表达桩蛋白mRNA,而T2A和神经元未表达桩蛋白mRNA;免疫荧光染色显示桩蛋白主要分布于T1A的胞浆及突起中。结论:桩蛋白在T1A中表达,但未表达于T2A和神经元中;本实验结果为进一步研究桩蛋白在T1A中的生物学作用奠定了基础。     

Hypoglycemia enhances ionotropic but reduces metabotropic glutamate responses in substantia nigra dopaminergic neurons

It is widely accepted that energy deprivation causes a neuronal death that is mainly determined by an increase in the extracellular level of glutamate. Consequently an excessive membrane depolarization and a rise in the intracellular concentration of sodium and calcium are produced. In spite of this scenario, the function of excitatory and inhibitory amino acids during an episode of energy failure has not been studied yet at a cellular level. In a model of cerebral hypoglycemia in the rat substantia nigra pars compacta, we measured neuronal responses to excitatory amino acid agonists. Under single-electrode voltage-clamp mode at -60 mV, the application of the ionotropic glutamate receptor agonists N-methyl-D-aspartate, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid, kainate, and the metabotropic group I agonist (S)-3,5-dihydroxyphenilglycine (DHPG) produced reversible inward currents in the dopaminergic cells. In addition, an outward current was caused by the superfusion of the metabotropic GABA(B) agonist baclofen. Glucose deprivation enhanced the inward responses caused by each ionotropic glutamate agonist. In contrast, hypoglycemia depressed the DHPG-induced inward current and the baclofen-induced outward current. These effects of hypoglycemia were reversible. To test whether a failure of the Na(+)/K(+) ATPase pump could account for the modification of the agonist-induced currents during hypoglycemia, we treated the midbrain slices with strophanthidin (1-3 microM). Strophanthidin enhanced the inward currents caused by glutamate agonists. However, it did not modify the GABA(B)-induced outward current. Our data suggest that glucose deprivation enhances the inward current caused by the stimulation of ionotropic glutamate receptors while it dampens the responses caused by the activation of metabotropic receptors. Thus a substantial component of the augmented neuronal response to glutamate, during energy deprivation, is very likely due to the failure of Na(+) and Ca(2+) extrusion and might ultimately favor excitotoxic processes in the dopaminergic cells.     

Naloxone prevents microglia-induced degeneration of dopaminergic substantia nigra neurons in adult rats

Resident microglia are involved in immune responses of the central nervous system and may contribute to neuronal degeneration and death. Here, we tested in adult rats whether injection of bacterial lipopolysaccharide (which causes inflammation and microglial activation) just above the substantia nigra, results in the death of dopaminergic substantia nigra pars compacta neurons. Two weeks after lipopolysaccharide injection, microglial activation was evident throughout the nigra and the number of retrogradely-labeled substantia nigra neurons was reduced to 66% of normal. This suggests that inflammation and/or microglial activation can lead to neuronal cell death in a well-defined adult animal model. The opioid receptor antagonist naloxone reportedly reduces release of cytotoxic substances from microglia and protects cortical neurons in vitro. Here, a continuous two-week infusion of naloxone at a micromolar concentration close to the substantia nigra, prevented most of the neuronal death caused by lipopolysaccharide, i.e. 85% of the neurons survived. In addition, with systemic (subcutaneous) infusion of 0. 1mg/d naloxone, 94% of the neurons survived. Naloxone infusions did not obviously affect the morphological signs of microglial activation, suggesting that naloxone reduces the release of microglial-derived cytotoxic substances. Alternatively, microglia might not cause the neuronal loss, or naloxone might act by blocking opioid receptors on (dopaminergic or GABAergic) neurons.Thus, local inflammation induces and the opioid antagonist naloxone prevents the death of dopaminergic substantia nigra neurons in adult rats. This may be relevant to the understanding of the pathology and treatment of Parkinson's disease, where these neurons degenerate.     

黄芪甲甙对大鼠LPS诱导原代培养多巴胺神经细胞的保护效应

目的:观察黄芪甲甙(AS-IV)对大鼠脂多糖(LPS)诱导多巴胺能细胞增殖的影响,检测炎症因子肿瘤坏死因子α(TNF-α)和诱导型一氧化氮合酶(iNOS)mRNA表达变化。方法:建立原代多巴胺细胞培养,加入LPS刺激,给予不同浓度AS-IV预处理。通过MTT方法检测多巴胺能细胞增殖情况,通过RT-PCR检测TNF-α、iNOSmRNA表达变化。结果:LPS刺激后多巴胺能细胞MTT值降低,经AS-IV预处理后MTT值升高。LPS刺激后TNF-α、iNOS mRNA表达上调;经AS-IV预处理后,TNF-α、iNOS mRNA表达明显下调(P<0.05)。结论:大鼠用AS-IV预处理可降低LPS对多巴胺能细胞毒性作用,提示AS-IV预处理可阻断LPS诱导多巴胺细胞变性和炎症变化,对中脑多巴胺能神经元具有保护性作用。     

Extrastriatal dopaminergic innervation of human basal ganglia.

A tyrosine-hydroxylase immunohistochemical analysis of the brains of normal human individuals has revealed nigrostriatal axons providing collaterals that arborize in the pallidum and subthalamic nucleus. These thin and varicose collaterals emerge from thick and smooth axons that course backward along the main output pathways of the basal ganglia, including the ansa lenticularis, the lenticular fasciculus and Wilson's pencils. Many of these fibers run within pallidal medullary laminae before reaching the putamen, whereas others climb along the reticular thalamic nucleus to reach the caudate nucleus. This extrastriatal innervation, which allows nigral dopaminergic neurons to directly affect the pallidum and subthalamic nucleus, may play a crucial role in the functional organization of human basal ganglia, in both health and disease.