Ligustrazine inhibits high voltage-gated Ca~(2+) and TTX-resistant Na~+ channels of primary sensory neuron and thermal nociception in the rat:a study on peripheral mechanism

Objective Ligustrazine, also named as tetramethylpyrazine, is a compound purified from Ligusticum chuanxiong hort and has ever been testified to be a calcium antagonist. The present investigation was to determine the antinoci-ceptive effect of ligustrazine and, if any, the peripheral ionic mechanism involved. Methods Paw withdrawal Latency ( PWL) to noxious heating was measured in vivo and whole-cell patch recording was performed on small dorsal root ganglion (DRG) neurons. Results Intraplantar injection of ligustrazine (0.5 mg in 25μl) significantly prolonged the withdrawal latency of ipsilateral hindpaw to noxious heating in the rat. Ligustrazine not only reversibly inhibited high-voltage gated calcium current of dorsal root ganglion (DRG) neuron in dose-dependent manner with IC50 of 1.89 mmol/L, but also decreased tetrodotoxin (TTX) -resistant sodium current in relatively selective and dose-dependent manner with IC50 of 2.49 mmol/L. Conclusion The results suggested that ligustrazine could elevate the threshold of thermal nociception through inhibiting the high-voltage gated calcium current and TTX-resistant sodium current of DRG neuron in the rat.     

Trigeminal amyloidoma: case report and review of the literature.

The authors present a case of amyloid infiltration involving the trigeminal nerve that mimicked a malignant cavernous sinus tumor with perineural tumor infiltration. A 64-year-old man presented with trigeminal nerve numbness. Imaging revealed a plaque-like enhancing lesion along the right lateral cavernous sinus extending anteriorly into Meckel's cave and involving the proximal V2 and V3 branches of the trigeminal nerve. The patient underwent an extradural frontotemporal craniotomy with middle fossa exposure of the cavernous sinus to diagnose and treat the presumed malignant cavernous sinus tumor. A reddish mass involving the lateral dural wall of the cavernous sinus was resected. The gasserian ganglion, V2, and V3, the latter of which was biopsied, were enlarged. Permanent histopathological studies showed microscopic eosinophilic, amorphous material, which stained positive for Congo red, and an absence of neoplastic cells. The final diagnosis was amyloidoma. Thus, amyloidomas can involve the trigeminal nerve or ganglia and should be considered in the differential diagnosis of a cavernous sinus lesion mimicking a tumor. Patients may have symptomatic improvement of trigeminal neuropathy with resection of the amyloidoma outside the nerve capsule that is compressing the nerve, while resection of the lesion from within the capsule may result in permanent trigeminal nerve dysfunction.     

A Complication of Stellate Ganglion Block?

Abstract: Stellate ganglion block is commonly used to treat the sympathetically maintained pain which may occur in one‐third of patients with complex regional pain syndrome type 1. A complication that followed a single block and presented a diagnostic dilemma for the ophthalmologist is reported.     

Effect of nuclear factor-κB p65 ASOND on I typ collagen expression and rat hepatic stellate cells proliferation

Objective Sstudy effect of nuclear factor-κB ASOND on I type collagen expression and rat hepatic stellate cells(HSC)proliferation.Methods Rat HSCs were separated by affusing and digestingof Ⅳ type collagenenzyme and density acentric method.Lipid-mediated NF-κB p65 ASOND(0.001,0.01,0.1,1μmol/L)Was transferred into rat HSCs.Toxicity of HSCs caused by NF-κB p65 ASOND and activity of LDH were determined by trypan blue staining.Proliferation affection of transferring NF-κB p65 ASOND into HSCs was determined by MTT.In different concentration NF-κB p65 ASOND.expression of Ⅰ type collagen stimulated by 1mg/L TNF-αwas determined by RT-PCR and ELISA.Results After transfection of NF-κB p65 ASODN,expression of NF-κB protein in HSCs was decreasing.Toxicity experiment indicated that NF-κB p65 ASOND of different concentration(0.001,0.01,0.1 and 1.0 μmol/L)had no effect on HSCs livability and LDH activity(P<0.05).Four different concentration NF-κ B p65 ASOND could restrain HSCs proliferation stimulated by 1 mg/L TNF-α.The expression of I type collagen and mRNA stimulated by 1mg/LTNF-αwas increased,and had a positive correlation with concentration(P>0.05).Conclusion NF-κB p65 ASOND may depress NF-κB activity to restrain HSCs proliferation and Ⅰ type collagen expression,and reduce extracellular matrix.     

Chronic opioid treatment of neuroblastoma X dorsal root ganglion neuron hybrid F11 cells results in elevated GM1 ganglioside and cyclic adenosine monophosphate levels and onset of naloxone-evoked decreases in membrane K+ currents

Prolongation of the action potential duration of dorsal root ganglion (DRG) neurons by low (nM) concentrations of opioids occurs through activation of excitatory opioid receptors that are positively coupled via G_s regulatory protein to adenylate cyclase. Previous results suggested GM1 ganglioside to have an essential role in regulating this excitatory response, but not the inhibitory (APD-shortening) response to higher (μM) opioid concentrations. Furthermore, it was proposed that synthesis of GM1 is upregulated by prolonged activation of excitatory opioid receptor functions. To explore this possibility we have utilized cultures of hybrid F11 cells to carry out closely correlated electrophysiological and biochemical analyses of the effects of chronic opioid treatment on a homogeneous population of clonal cells which express many functions characteristic of DRG neurons. We show that chronic opioid exposure of F11 cells does, in fact, result in elevated levels of GM1 as well as cyclic adenosine monophosphate (AMP), concomitant with the onset of opioid excitatory supersensitivity as manifested by naloxone-evoked decreases in voltage-dependent membrane K⁺ currents. Such elevation of GM1 would be expected to enhance the efficacy of excitatory opioid receptor activation of the G_s/adenylate cyclase/cyclic AMP system, thereby providing a positive feedback mechanism that may account for the remarkable supersensitivity of chronic opioid-treated neurons to the excitatory effects of opioid agonists as well as antagonists. These in vitro findings may provide novel insights into the mechanisms underlying naloxone-precipitated withdrawal syndromes and opioid-induced hyperalgesia after chronic opiatf addiction in vivo. © 1995 Wiley-Liss, Inc.     

Development of neurochemical separation of ON and OFF channels at retinal ganglion cells

Anatomical and physiological segregation of neurons into ON (brightening detector) and OFF (darkening detector) channels in the retina and subsequent visual system ensure the high sensitivity required for contrast detection and spatial discrimination. This segregation is finest at the visual axis. Neurochemically, ON and OFF ganglion cells at the visual axis seem to be distinguished by different inhibitory transmitters but not excitatory transmitters. Microiontophoretic studies of inhibitory transmitters on the retinal ganglion cells in kittens and adult cats suggest that this neurochemical distinction is poor in immature ganglion cells at the visual axis. Initially both ON and OFF cells seem to be supplied by GABAergic, glycinergic, and catecholaminergic amacrine cells, but in adults, ON cells remain supplied only by GABAergic amacrines, while OFF cells are supplied by glycinergic amacrines. Postnatal elimination of multiple inputs and strengthening of the appropriate inputs, as seen in the central nervous system, also seem to occur at the retinal neurotransmitter synapses during development.     

Daily changes in presynaptic cholinergic activity of rat sympathetic superior cervical ganglion

The in vitro capacity of sympathetic superior cervical ganglia (SCG) to take up [³H]choline from the extracellular medium, to synthesize acetylcholine from [³H]choline, and to release [³H]acetylcholine in response to a high K⁺ concentration, were examined in rats throughout a 24-h cycle. Both the release of [³H]acetylcholine and the synthesis of [³H]acetylcholine from [³H]choline exhibited significant diurnal variations, showing maxima during the first half of the night. After these maxima, nocturnal acetylcholine release and synthesis decayed to daytime levels and remained low until the end of the night. [³H]Choline uptake by rat SCG did not vary significantly throughout a 24-h period. A 1.5-h exposure of rats to darkness at the 5th hour of light phase of the daily photoperiod did not change significantly any parameter studied. A 20-min, 5-Hz, electrical stimulation of the preganglionic trunk of SCG excised from rats at noon increased significantly subsequent K⁺-induced [³H]acetylcholine release but did not change [³H]acetylcholine synthesis. In decentralized SCG of rats subjected to a unilateral SCG decentralization and a contralateral sham-operation 7 days earlier, [³H]acetylcholine release and synthesis were highly reduced or abolished at the decentralized side, while [³H]choline uptake remained unaltered. The present results suggest that an activation of preganglionic rat SCG neurons takes place during the first half of the scotophase.     

The outcome of ganglion clipping in hyperhidrosis and blushing

A total of 114 patients with various sympathetic disorders underwent endoscopic sympathetic block over different thoracic ganglions by the clipping method. The advantages of this method include the recognition of the clipped level, changeability, and reversibility. However, 4.4% of patients were unilaterally clipped at the wrong level.     

Repetitive firing properties in subpopulations of the chick Edinger Westphal nucleus.

The avian Edinger Westphal nucleus, through the ciliary ganglion, controls accommodation, iris constriction, and blood flow through the choroid. In live brainstem slices, the nucleus is easily identifiable as an olive-shaped cluster of neurons dorsal to the oculomotor nerve and nucleus. Intracellular recordings from neurons in the nucleus identified two classes of responses to sustained (300 to 500 ms) injections of depolarizing current. One set of cells fired action potentials for the duration of the pulse while a second set of cells fired action potentials only transiently, during the first 50 to 100 ms, after which they remained silent regardless of the size of the depolarization. Intracellular recordings followed by injections of the fluorescent dye lucifer yellow revealed that repetitively firing cells were located in the lateral half of the nucleus while non-repetitively or transiently firing cells were located in the medial half. These locations correspond to different Edinger Westphal subdivisions which have distinct inputs and target populations. The varying firing patterns are discussed with reference to the known functions of the subdivisions in which they occur. Replacement of calcium by magnesium in the extracellular medium had no effect on the number of action potentials fired by non-repetitively firing cells, suggesting that a calcium-activated potassium current is not responsible for suppressing repetitive firing in these cells. In contrast, in repetitively firing cells removal of extracellular calcium increased the frequency of action potential discharge and decreased the amplitude of afterhyperpolarizations following single action potentials. Addition of cadmium to the bath medium had similar effects.(ABSTRACT TRUNCATED AT 250 WORDS)     

还原型谷胱甘肽对大鼠肝星状细胞TIMP—1表达的影响

目的 研究还原型谷胱甘肽对大鼠肝星状细胞（hepatic stellate,cells,HSC)中金属蛋白酶1组织抑制因子（TIMP－2）表达的影响。从分子和蛋白水平探讨还原型谷胱甘肽对大鼠肝纤维化的作用和可能机制。方法 采用50％CCl4制备大鼠肝纤维化模型，在造模过程中给予还原型谷胱甘肽进行干预。应用RT－PCR才Western Blot技术，在分子和蛋白水平检测体外分离大鼠HSC中的TIMP－1的表达情况。结果 还原型谷胱甘肽干预组与模型组和正常对照组相比，HSC中TIMP的表达降低（P＜0．05）。结论 还原型谷胱甘肽的干预可下调大鼠HSC中TIMP－1的表达，对实验性肝纤维化起到减轻作用。