香萱益神方对血管性痴呆模型大鼠神经元凋亡机制研究

目的:探讨香萱益神方治疗血管性痴呆(VD)模型大鼠认知功能作用及其对神经元凋亡机制的研究。方法:两血管阻断法建立VD大鼠模型,给予中药方香萱益神方灌胃治疗6周,分别于造模后、中药喂养6周后进行Morris水迷宫行为学检测,测试大鼠认知行为能力改变,行为学测试结束后,检测VD模型大鼠海马中海马组织脑源性神经营养因子(BDNF)表达水平的变化。结果:香萱益神方治疗6周后,血管性痴呆大鼠模型学习记忆能力得到改善,上调脑内海马组织神经营养因子水平,海马神经元凋亡率下降。结论:香萱益神方是治疗血管性痴呆的有效方剂,可以有效改善VD大鼠模型认知行为功能的障碍情况,起到减少海马神经元细胞凋亡,诱导海马神经元细胞修复的作用。香萱益神方可能是通过激活BDNF相关通路,起到保护海马神经元的作用。     

大鼠脊髓广动力范围神经元早成分放电对晚成分放电的调控

采用细胞外记录方法 ,通过选择性阻断有髓粗纤维的传入 ,观察大鼠脊髓背角深层广动力范围神经元(WDR)早成分放电对晚成分放电及其潜伏期的影响。结果显示 :0 3mg蛇毒溶液注入到大鼠坐骨神经鞘膜下后 ,WDR神经元出现如下动态变化 :(1)诱发放电的早成分显著减少 ,每次刺激所诱发的早成分放电个数由 6 94± 0 4 8降至 0 75± 0 2 5 (P <0 0 5 ) ,15min左右几近完全消失。 (2 )随着早成分放电的减少 ,晚成分放电则逐渐增加 ,放电数从 9 94± 0 9增加到 4 5 94± 1 16 (P <0 0 5 )。此时轻刷WDR神经元的感受野不能引起其活动改变 ,但伤害性齿镊夹捏仍可引起WDR神经元放电增多。 (3)晚成分放电的潜伏期缩短 ,即宁静期的时程变短 ,由给蛇毒前的116 83± 3 6 7ms降至 4 6 86± 1 13ms(P <0 0 1)。提示 :A纤维传入冲动在调控WDR神经元对伤害性刺激传入的反应性和兴奋性上具有重要作用     

Anti-apoptotic effects of hyperoside via inhibition of NR2B-containing NMDA receptors

Hyperoside (Hyp) is a flavonoid compound isolated from a folk remedy, Rhododendron ponticum L. leaves. It has been shown to have neuroprotective effects both in vivo and in vitro. However, little is known about the effects of Hyp on the neuronal apoptosis induced by glutamate. The present study showed that Hyp significantly attenuated, in a concentration-dependent manner, the apoptosis induced by the exposure of cultured neurons to NMDA. Western blot analysis revealed that Hyp antagonized the expression of excess NR2B-containing NMDA receptors; however, it had no effect on the expression of NR2A-containing NMDA receptors. Our results demonstrate that the neuroprotective effect of Hyp owes, at least partially, to its differential modulation of NR2A- and NR2B-containing NMDA receptors.     

羟丁酸钠对皮质神经元缺氧复氧损伤的保护作用(英文)

目的　研究羟丁酸钠 (GHB)对缺氧复氧脑损伤的保护机制。方法　用原代培养大鼠皮层神经元建立缺氧复氧损伤模型 ,缺氧 2h复氧 6h ;缺氧前30min在培养基内加入GHB(5 ,2 0 ,80mmol·L- 1) ,观察神经元的形态学变化 ,检测培养基中乳酸脱氢酶漏出率及细胞中丙二醛 (MDA)含量、超氧化物歧化酶 (SOD)和谷胱甘肽过氧化物酶 (GSH Px)的活力。结果　缺氧复氧降低神经元生存率 ,增加乳酸脱氢酶 (LDH)漏出及MDA含量 ,而导致SOD及GSH Px活力下降。GHB 2 0 ,80mmol·L- 1预处理能显著提高缺氧复氧神经元的生存率 ,减少LDH的漏出及MDA的生成 ,升高SOD和GSH Px的活力。结论　GHB对缺氧复氧引起的神经元损伤的保护作用与它保护抗氧化酶的作用有关。     

Baclofen-induced disinhibition in area CA1 of rat hippocampus is resistant to extracellular Ba

The mechanism of disinhibition produced by (±)-baclofen was studied using intracellular recording in area CA1 of rat hippocampal slices. Baclofen reversibly depressed monosynaptic IPSPs evoked by direct activation of interneurons in the presence of the excitatory amino acid receptor antagonists 6,7-dinitroquinoxaline-2,3-dione (DNQX) andd,l-2amino-5-phosphonovalerate (APV). Ba²⁺ prevented baclofen-induced hyperpolarization of pyramidal neurons but not depression of monosynaptic IPSPs by baclofen. Baclofen reversibly depressed monosynaptic IPSPs when applied close to the recording site, but was ineffective when applied close to the stimulating site in stratum radiatum. These results suggest that baclofen disinhibits pyramidal neurons in area CA1 of the rat hippocampus by activating receptors on the terminals of inhibitory neurons that are coupled to a Ba²⁺-insensitive effector mechanism.     

铅对大鼠海马神经元胞质PKC活性的影响

目的 :观察不同低浓度醋酸铅不同染铅时间对大鼠海马神经元原代培养细胞胞质蛋白激酶C(PKC)活性及神经元细胞生长的影响。方法 :出生 4～ 8dWistar大鼠海马神经元原代细胞培养 ,显微照相 ,并不同时间不同浓度染铅 ,应用改良的Takai法测定PKC活性的变化。结果 :0 .1～ 1.0 μmol/L染铅 ,PKC活性依浓度依赖方式被激活 ,染铅浓度 >1.0 μmol/L ,PKC活性下降 ;染铅 15min后PKC活性升高并保持。低浓度醋酸铅并可抑制原代神经元细胞生长 ,呈浓度依赖方式。结论 :低浓度醋酸铅可持续激活大鼠海马神经元原代培养细胞胞质PKC ,抑制原代神经元细胞生长。     

Frontotemporal dementia, motor neuron disease and tauopathy: clinical and neuropathological study in a family

We report a familial disorder occurring in three patients that presented as frontotemporal dementia (FTD). A neuropathological study was performed in a 58-year-old patient, who developed FTD 2 years prior to the onset of motor neuron disease (MND), and died at age 62. Lesions indicative of associated MND were observed: neuronal loss in the anterior horns of the spinal cord, Bunina bodies, axonal spheroids, degeneration of the pyramidal tracts, and of FTD: decreased neuronal density and laminar microvacuolation of layers II and III in the frontal and temporal cortex. Ubiquitin-only-immunoreactive changes were found in the spinal cord and medulla, but were absent from the temporal and frontal cortex. There were also widespread deposits of various neuronal and glial inclusions containing abnormally phosphorylated tau protein, the Western blotting pattern of which was characterized by two major bands of 64 and 69 kDa. There were no abnormalities of the entire coding sequences of microtubule-associated protein tau (MAPT) and copper-zinc superoxide dismutase (SOD₁) genes. Our results suggest that FTD associated with MND can be caused by a larger spectrum of neuropathological lesions than commonly accepted.     

l-DOPA induces concentration-dependent facilitation and inhibition of presynaptic acetylcholine release in the guinea-pig submucous plexus

Neurotransmitter- or neuromodulator-like actions ofl-DOPA were investigated with intracellular recordings from submucous plexus neurons of the guinea-pig caecum.l-DOPA at 30 nM augmented the amplitude of fast EPSPs, but did not affect depolarizations elicited by puff application of acetylcholine (ACh). The augmenting effect ofl-DOPA on the fast EPSPs was counteracted byl-DOPA methyl ester. The fast EPSPs were depressed by 10 μMl-DOPA, but transiently augmented after rinsing the drug.l-DOPA methyl ester did not affect the inhibitory action ofl-DOPA on the fast EPSPs, but antagonized the potentiation following the inhibition. The depolarization elicited by exogenously applied. ACh was inhibited by 10 μMl-DOPA. Intracellular Ca²⁺ concentrations ([Ca²⁺]_i) of the neuronal soma were measured with fura-2 microfluorophotometry. The transient increase in the [Ca²⁺]_i evoked by the somatic action potential (Δ[Ca²⁺]_AP) was facilitated by 30 nMl-DOPA, but decreased by the drug at 10 μM. It is concluded thatl-DOPA at low concentrations enhances the Δ[Ca²⁺]_AP, increasing the neurotransmitter release, but at high dose diminishes the Δ[Ca²⁺]_AP, inhibiting the neurotransmission.     

Optogenetically enhanced axon regeneration: motor versus sensory neuron‐specific stimulation

Brief neuronal activation in injured peripheral nerves is both necessary and sufficient to enhance motor axon regeneration, and this effect is specific to the activated motoneurons. It is less clear whether sensory neurons respond in a similar manner to neuronal activation following peripheral axotomy. Further, it is unknown to what extent enhancement of axon regeneration with increased neuronal activity relies on a reflexive interaction within the spinal circuitry. We used mouse genetics and optical tools to evaluate the precision and selectivity of system‐specific neuronal activation to enhance axon regeneration in a mixed nerve. We evaluated sensory and motor axon regeneration in two different mouse models expressing the light‐sensitive cation channel, channelrhodopsin (ChR2). We selectively activated either sensory or motor axons using light stimulation combined with transection and repair of the sciatic nerve. Regardless of genotype, the number of ChR2‐positive neurons whose axons had regenerated successfully was greater following system‐specific optical treatment, with no effect on the number of ChR2‐negative neurons (whether motor or sensory neurons). We conclude that acute system‐specific neuronal activation is sufficient to enhance both motor and sensory axon regeneration. This regeneration‐enhancing effect is likely cell autonomous.