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The analgesic effect on neuropathic pain of retrogradely transported botulinum neurotoxin A involves Schwann cells and astrocytes.

In recent years a growing debate is about whether botulinum neurotoxins are retrogradely transported from the site of injection. Immunodetection of cleaved SNAP-25 (cl-SNAP-25), the protein of the SNARE complex targeted by botulinum neurotoxin serotype A (BoNT/A), could represent an excellent approach to investigate the mechanism of action on the nociceptive pathways at peripheral and/or central level. After peripheral administration of BoNT/A, we analyzed the expression of cl-SNAP-25, from the hindpaw's nerve endings to the spinal cord, together with the behavioral effects on neuropathic pain

Hermansky-Pudlak protein complexes, AP-3 and BLOC-1, differentially regulate presynaptic composition in the striatum and hippocampus.

Endosomal sorting mechanisms mediated by AP-3 and BLOC-1 are perturbed in Hermansky-Pudlak Syndrome, a human genetic condition characterized by albinism and prolonged bleeding (OMIM #203300). Additionally, mouse models defective in either one of these complexes possess defective synaptic vesicle biogenesis (Newell-Litwa et al., 2009). These synaptic vesicle phenotypes were presumed uniform throughout the brain. However, here we report that AP-3 and BLOC-1 differentially regulate the composition of presynaptic terminals in the striatum and dentate gyrus of the hippocampus. Quantitative immunoel

Dynamics of SNARE assembly and disassembly during sperm acrosomal exocytosis.

The dynamics of SNARE assembly and disassembly during membrane recognition and fusion is a central issue in intracellular trafficking and regulated secretion. Exocytosis of sperm's single vesicle--the acrosome--is a synchronized, all-or-nothing process that happens only once in the life of the cell and depends on activation of both the GTP-binding protein Rab3 and of neurotoxin-sensitive SNAREs. These characteristics make acrosomal exocytosis a unique mammalian model for the study of the different phases of the membrane fusion cascade. By using a functional assay and immunofluorescence techniq

Endogenous activation of mGlu5 metabotropic glutamate receptors contributes to the development of nigro-striatal damage induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in mice.

We combined the use of knock-out mice and subtype-selective antagonists [2-methyl-6-(phenylethynyl)pyridine (MPEP) and (E)-2-methyl-6-(2-phenylethenyl)-pyridine (SIB1893)] to examine whether endogenous activation of mGlu5 metabotropic glutamate receptors contributes to the pathophysiology of nigro-striatal damage in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of parkinsonism. High doses of MPTP (four injections of 20 mg/kg, i.p., every 2 hr) induced a high mortality rate and a nearly total degeneration of the nigro-striatal pathway in wild-type mice. mGlu5 knock-out mice were

Synaptic remodeling and free radical formation after brain contusion injury in the rat.

The purpose of this study was to explore whether bilateral frontal cortex contusion in rats would demonstrate changes relevant for understanding the pathology of frontal lobe injury in humans. Rats were allowed to survive for 3, 7, or 18 days postinjury (dpi). In the contused rats, albumin was trapped in frontal cortices, as well as in other brain areas, showing that neurons were exposed to plasma components. In the sham-operated rats, which had only craniotomy but no penetration of dura, the level of trapped albumin was also increased compared to intact controls, suggesting a partial lesion-l

Centella Asiatica поощряет антиоксидантное гениевые экспрессии и митохондриальное окисляющее дыхание в экспериментальном аутоиммунном энцефаломелите.

Справочная информация/задачи: Centella asiatica (L.) — традиционная ботаническая медицина, применяемая при старении и слабоумии. Водные выдержки из C. asiatica (CAW) использовались для лечения нейропсихиатрических симптомов в соответствующих моделях животных и связаны с увеличением генов антиоксидантов (ARE) и улучшением митохондриальной дыхательной функции и нейронного здоровья. Поскольку множественный склероз (MS) разделяет ее нейрогенеративную патологию окислительного стресса и митохондриальной дисфункции со старением и слабоумием, нейропсихиатрические симптомы в MS могут также выиграть от

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… ARE Gene Expression and Mitochondrial Respiratory Activity Gene expression was quantified in cortical synaptosomes. … Mitochondrial respiratory activity was assessed in cortical synaptosomes using the Seahorse XFe96 Analyzer (Agilent, Santa Clara, CA, USA). The total protein concentration of the synaptosomal preparation for each mouse was determined using a bicinchoninic acid (BCA) assay. …

Identification of a Novel Sequence Motif Recognized by the Ankyrin Repeat Domain of zDHHC17/13 S-Acyltransferases.

S-Acylation is a major post-translational modification affecting several cellular processes. It is particularly important for neuronal functions. This modification is catalyzed by a family of transmembrane S-acyltransferases that contain a conserved zinc finger DHHC (zDHHC) domain. Typically, eukaryote genomes encode for 7-24 distinct zDHHC enzymes, with two members also harboring an ankyrin repeat (AR) domain at their cytosolic N termini. The AR domain of zDHHC enzymes is predicted to engage in numerous interactions and facilitates both substrate recruitment and S-acylation-independent functi

Acute stress impairs hippocampal mossy fiber-CA3 long-term potentiation by enhancing cAMP-specific phosphodiesterase 4 activity.

The mossy fiber synapses onto hippocampal CA3 neurons show unique molecular features and a wide dynamic range of plasticity. Although acute stress has been well recognized to alter bidirectional long-term synaptic plasticity in the hippocampal CA1 region and dentate gyrus, it remains unclear whether the same effect may also occur at the mossy fiber-CA3 synapses. Here, we report that hippocampal slices prepared from adult mice that had experienced an acute unpredictable and inescapable restraint tail-shock stress showed a marked impairment of long-term potentiation (LTP) induced by high-frequen

Mechanism of toxicity of the branched-chain fatty acid phytanic acid, a marker of Refsum disease, in astrocytes involves mitochondrial impairment.

Phytanic acid is a saturated branched-chain fatty acid, which is formed by bacterial degradation of chlorophyll in the intestinal tract of ruminants. The methyl group in beta-position prevents degradation of phytanic acid by the beta-oxidation pathway. Therefore, degradation of phytanic acid is initiated by alpha-oxidation in peroxisomes. The inherited peroxisomal disorder Refsum disease is characterised by accumulation of phytanic acid. Unusually high concentrations of phytanic acid can be found in the plasma of Refsum disease patients, who suffer from neurodegeneration and muscle dystrophy.

Brain-derived neurotrophic factor induces mammalian target of rapamycin-dependent local activation of translation machinery and protein synthesis in neuronal dendrites.

In neurons, perisynaptic or dendritic translation is implicated in synapse-wide alterations of function and morphology triggered by neural activity. The molecular mechanisms controlling local translation activation, however, have yet to be elucidated. Here, we show that local protein synthesis and translational activation in neuronal dendrites are upregulated by brain-derived neurotrophic factor (BDNF) in a rapamycin and small interfering RNA specific for mammalian target of rapamycin (mTOR)-sensitive manner. In parallel, BDNF induced the phosphorylation of tuberin and the activation of mTOR i

Long-term potentiation selectively expressed by NMDA receptors at hippocampal mossy fiber synapses.

The mossy fiber to CA3 pyramidal cell synapse (mf-CA3) provides a major source of excitation to the hippocampus. Thus far, these glutamatergic synapses are well recognized for showing a presynaptic, NMDA receptor-independent form of LTP that is expressed as a long-lasting increase of transmitter release. Here, we show that in addition to this "classical" LTP, mf-CA3 synapses can undergo a form of LTP characterized by a selective enhancement of NMDA receptor-mediated transmission. This potentiation requires coactivation of NMDA and mGlu5 receptors and a postsynaptic calcium rise. Unlike classic

Ion regulation of homotypic vacuole fusion in Saccharomyces cerevisiae.

Biological membrane fusion employs divalent cations as protein cofactors or as signaling ligands. For example, Mg2+ is a cofactor for the N-ethylmaleimide-sensitive factor (NSF) ATPase, and the Ca2+ signal from neuronal membrane depolarization is required for synaptotagmin activation. Divalent cations also regulate liposome fusion, but the role of such ion interactions with lipid bilayers in Rab- and soluble NSF attachment protein receptor (SNARE)-dependent biological membrane fusion is less clear. Yeast vacuole fusion requires Mg2+ for Sec18p ATPase activity, and vacuole docking triggers an e

NMDA receptor-mediated immediate Ser831 phosphorylation of GluR1 through CaMKIIalpha in rat hippocampus during early global ischemia.

The phosphorylation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors subunit GluR1 at Ser831 has been implicated in the regulation of AMPA receptors channel. In this paper, Ser831 phosphorylation of GluR1 in rat hippocampus was investigated, which significantly increased during early global ischemia. To further illustrate the underlying mechanisms, calcium/calmodulin-dependent kinase IIalpha (CaMKIIalpha) inhibitor 1-[N,O-bis-(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN62), CaM antagonist trifluoperazine (TFP), N-methyl-D-aspartate (NMDA) rece

Tapentadol: A Review of Experimental Pharmacology Studies, Clinical Trials, and Recent Findings.

Tapentadol is an analgesic compound that acts centrally to attenuate pain. Previous studies have shown that tapentadol has dual mechanisms of action as a mu-opioid receptor agonist and noradrenaline re-uptake inhibition. Therefore, tapentadol provides a great advantage over classic opioids in pain management from nociceptive to neuropathic. Cumulative evidence from in vitro data suggests that tapentadol effect of norepinephrine re-uptake could be a new target that overcomes other classic opioids in chronic neuropathic pain. Compared to tramadol and other opioids, tapentadol is associated with

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… Tapentadol was also tested for its reuptake inhibitor activity against NE in a rat synaptosomal reuptake assay. It was found that tapentadol inhibited NE reuptake with a Ki value of 0.48 µM. … Moreover, tapentadol was tested for reuptake inhibitor activity of 5HT and found to have a Ki value of 2.37 µM in rat synaptosomes. In a binding assay to the human recombinant NE transporter, the Ki value was 8.80 µM and to the human recombinant 5HT was 5.28 µM. …

[Mechanism of Shuangshen Yiwei Granules in regulating gastric acid secretion and blocking malignant progression of chronic atrophic gastritis with gastric intestinal metaplasia].

This study aims to explore the mechanism of Shuangshen Yiwei Granules, an empirical prescription developed by Professor LU Zhi-zheng(a master of TCM), in regulating gastric acid secretion and impeding malignant progression of chronic atrophic gastritis with gastric intestinal metaplasia(GIM). Seventy-two specific-pathogen free(SPF) Wistar male rats were randomly divided into a normal group and a modeling group. GIM model rats were established by a four-factor GIM induction protocol involving "N-methyl-N'-nitro-N-nitrosoguanidine(MNNG), ranitidine, irregular feeding, and sodium salicylate&

RNAi-induced gene silencing by local electroporation in targeting brain region.

Genetic manipulation for "knockout" (KO) is a useful tool for characterizing a target gene. However, its shortcomings that need to be overcome hinder its easy and ready usage in ordinary laboratories. Here we describe a knockdown technique termed the RNA interference (RNAi)-induced gene silencing by local electroporation (RISLE). Small interfering RNA (siRNA) introduction by electroporation into a specific brain region results in a marked reduction in the expression levels of both the mRNA and protein of the target genes such as GluR2 and Cox-1 without affecting the expression levels of protei

Basal calcium entry in vascular smooth muscle.

Basal calcium leak into smooth muscle was identified 30 years ago yet remains poorly understood. We characterized this leak measuring 45Ca2+ uptake into cultured rat aortic smooth muscle cells. Wash solution (0 degrees C) containing lanthanum (3 mM) removed extracellular tracer and increased cellular 45Ca2+ retention more effectively than EGTA (0.2 mM). Basal Ca2+ entry was 1.45 x 10(9) Ca2+ x cell(-1) x min(-1). This translated to approximately 250 micromol(-1) x min(-1) given cell volumes of 4-15 pl as determined by 3-D image reconstruction. Gadolinium (100 microM) blocked 80% of the leak an

Disulfide bridge reorganization induced by proline mutations in maurotoxin.

Maurotoxin (MTX) is a 34-residue toxin that has been isolated from the venom of the chactidae scorpion Scorpio maurus palmatus, and characterized. Together with Pi1 and HsTx1, MTX belongs to a family of short-chain four-disulfide-bridged scorpion toxins acting on potassium channels. However, contrary to other members of this family, MTX exhibits an uncommon disulfide bridge organization of the type C1-C5, C2-C6, C3-C4 and C7-C8, versus C1-C5, C2-C6, C3-C7 and C4-C8 for both Pi1 and HsTx1. Here, we report that the substitution of MTX proline residues located at positions 12 and/or 20, adjacent

Adaptive changes in the nigrostriatal pathway in response to increased 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurodegeneration in the mouse.

Although several adaptive mechanisms have been identified that mask the existence of Parkinson's disease and delay the onset and aggravation of motor symptoms, the timescale and implications of this compensatory process remain an enigma. In order to examine: (i) the nature of the dopaminergic adaptive mechanisms that come into action; (ii) their sequential activation in relation to the severity of degeneration; and (iii) their efficacy with regard to the maintenance of a normal level of basal ganglia activity, we analysed the brains of mice treated daily with 1-methyl-4-phenyl-1,2,3, 6-tetrahy

WIP modulates dendritic spine actin cytoskeleton by transcriptional control of lipid metabolic enzymes.

We identify Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP) as a novel component of neuronal synapses whose absence increases dendritic spine size and filamentous actin levels in an N-WASP/Arp2/3-independent, RhoA/ROCK/profilinIIa-dependent manner. These effects depend on the reduction of membrane sphingomyelin (SM) due to transcriptional upregulation of neutral sphingomyelinase (NSM) through active RhoA; this enhances RhoA binding to the membrane, raft partitioning and activation in steady state but prevents RhoA changes in response to stimulus. Inhibition of NSM or SM addit