Cytokeratin localization in toe pads of the anuran amphibian Philautus annandalii (Boulenger, 1906)

We have examined cytokeratin distribution and their nature in toe pads of the Himalayan tree-frog Philautus annandalii. Toe pads are expanded tips of digits and show modifications of their ventral epidermis for adhesion. The toe pad epidermal cells, being organized into 3–4 rows, possess keratin bundles, especially in surface nanostructures that are involved in adhesion. Immunohistochemical localization using a pan-cytokeratin antibody revealed that cytokeratin immunoreactivity is the strongest in the mid- to basal cell rows of the epidermis, which parallels our previous ultrastructural observation of dense keratin bundles present in this part of the epidermis. The remainder of the epidermis (i.e., the superficial cell layer) showed little immunoreactivity. Immunoblot analysis revealed that toe-pads possessed keratins prominently in the molecular mass of 50 kDa. Possible presence of keratin 5 in toe pad epidermis has been correlated with its usual distribution pattern in mammalian epidermis.     

Haloperidol treatment at pre-exposure phase reduces the disturbance of latent inhibition in rats with neonatal ventral hippocampus lesions

Animals with neonatal ventral hippocampal lesions develop during or after adolescence abnormal behaviors related to schizophrenia such as anxiety and latent inhibition disruption. The aim of this study was to test whether haloperidol injection prior to pre-exposure session in the latent inhibition test would facilitate latent inhibition.     

Eating-Induced Dopamine Release from Mesolimbic Neurons Is Mediated by NMDA Receptors in the Ventral Tegmental Area: A Dual-Probe Microdialysis Study

Abstract: This study was aimed at identifying the neuronal pathways that mediate the eating-induced increase in the release of dopamine in the nucleus accumbens of the rat brain. For that purpose, a microdialysis probe was implanted in the ventral tegmental area and a second probe was placed in the ipsilateral nucleus accumbens. Receptor-specific compounds acting on GABA_A (40 µ M muscimol; 50 µ M bicuculline), GABA_B (50 µ M baclofen), acetylcholine (50 µ M carbachol), NMDA [30 µ M (±)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP)], and non-NMDA [300 µ M 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)] receptors were infused into the ventral tegmental area by retrograde dialysis, whereas extracellular dopamine was recorded in the ipsilateral nucleus accumbens. Intrategmental infusion of muscimol or baclofen decreased extracellular dopamine in the ipsilateral nucleus accumbens; CPP and CNQX were without effect, and bicuculline and carbachol increased dopamine release. During infusion of the various compounds, food-deprived rats were allowed to eat for 10 min. The infusions of muscimol, bicuculline, baclofen, carbachol, and CNQX did not prevent the eating-induced increase in extracellular dopamine in the nucleus accumbens. However, during intrategmental infusion of CPP, the eating-induced increase in extracellular dopamine in the nucleus accumbens was suppressed. These results indicate that a glutamatergic projection to the ventral tegmental area mediates, via an NMDA receptor, the eating-induced increase in dopamine release from mesolimbic dopamine neurons.     

梅毒螺旋体膜抗原基因在毕赤酵母中的表达和蛋白纯化

以梅毒螺旋体(Treponema pallidumsubsp.pallidum)Nichols菌株基因组DNA为模板,通过PCR扩增梅毒螺旋体47kDa、17kDa和15kDa 3个膜抗原基因,克隆进毕赤酵母表达载体pPICZ B,构建重组表达载体pTP47、pTP17、pTP15,转化酵母菌株GS115,甲醇诱导表达。表达菌体裂解后通过镍离子亲和层析获得3个抗原与6xHis tag的融合蛋白,重组蛋白的获得量分别为His-TP15:4.8mg/L;His-TP 17:6.6mg/L;His-TP47:25mg/L,经SDS-PAGE鉴定纯度都在96%以上,ELISA鉴定均具有很好的抗原性。从而首次在毕赤酵母中表达出梅毒螺旋体膜抗原,为梅毒血清学检测方法开辟了新的抗原制备途径。     

Effects of Locally Applied Cocaine, Lidocaine, and Various Uptake Blockers on Monoamine Transmission in the Ventral Tegmental Area of Freely Moving Rats: A Microdialysis Study on Monoamine Interrelationships

Abstract: Microdialysis was used to compare the effect of local perfusion of cocaine with that of functionally similar compounds on extracellular norepinephrine, dopamine, and serotonin (measured simultaneously) in the ventral tegmental area of freely moving rats. Tetrodotoxin (1 µ M ) potently inhibited both basal and cocaine-induced dialysate monoamine outputs. The local anesthetic lidocaine produced little or no effect on the monoamine output, whereas all uptake blockers tested (at 0.1–1,000 µ M ) increased the monoamine output in a dose-dependent manner. The selective norepinephrine-uptake blockers desipramine and nisoxetine did not show any selectivity for norepinephrine, whereas the selective serotonin-uptake blockers fluoxetine and citalopram, as well as the selective dopamine-uptake blocker GBR 12935, preferentially (but not exclusively) increased their target amine. Cocaine at low concentrations (1–10 µ M ) increased the three amines similarly, but at higher concentrations (100–1,000 µ M ) caused a relatively higher dopamine output. A positive relationship between blocker-induced dialysate norepinephrine and dopamine outputs suggests significant interactions between monoamine systems. The present results indicate that cocaine's action in the ventral tegmental area involves not only a dopamine-, but also a norepinephrine- and a serotonin-related component, and that cocaine-induced monoamine increase is independent of its local anesthetic property.     

Dopamine D3 (Auto)receptors Inhibit Dopamine Release in the Frontal Cortex of Freely Moving Rats In Vivo

Abstract: In freely moving rats, the novel, selective dopamine (DA) D₃ receptor agonist PD 128,907 dose-dependently [effective dose (ED₂₅) = 0.07 mg/kg, s.c.] reduced dialysate levels of DA in the frontal cortex, a structure innervated by the ventral tegmental area (VTA). This action of PD 128,907 (0.16 mg/kg, s.c.) was abolished by a selective DA D₃ receptor antagonist S 14297 (1.25 mg/kg, s.c.), which alone did not modify levels of DA. In contrast to S 14297, its inactive distomer, S 17777, did not modify the actions of PD 128,907. In addition, PD 128,907 dose-dependently and potently inhibited the firing rate of VTA-localized neurons in anesthetized rats (ED₅₀ = 0.001 mg/kg, i.v.). S 14297, but not S 17777, completely reversed the actions of PD 128,907 (0.005 mg/kg, i.v.) with a 50% inhibitory dose of 0.03 mg/kg, i.v. and did not itself significantly modify the firing rate. In conclusion, these data provide the first direct evidence that DA D₃ (auto)receptors modulate (inhibit) the release of DA in the frontal cortex.     

Isolation and Characterization of Multilayered Sheath Membrane Rich in Glucocerebroside from Shrimp Ventral Nerve

A membrane fraction rich in glucocerebroside was isolated from homogenates of ventral nerves of pink shrimp (Penaeus duorarum) by sucrose gradient centrifugation. The membrane fraction was observed at 0.15 M sucrose and was rich in lipids (lipid/protein ratio approximately 15:1). Electron microscopy showed that the fraction was derived from myelin-like multilayered glial membrane ensheathing axons, which has morphological similarities to myelin. Most of the lipids in shrimp nerve, including glucocerebroside, sphingomyelin, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and ethanolamine-plasmalogen, as well as cholesterol, appeared to be concentrated in this fraction. The fatty acids of these phospholipids were exclusively saturated or monounsaturated with C14-C26 chain lengths. The aldehyde moiety of plasmalogens contained only saturated C14-C18 carbon chains. Like glucocerebrosides, the sphingoid base of sphingomyelin consisted mainly of C14-C16 sphingenines and sphinganines, but they also contained significant amounts of C19 and C20 sphinganines. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the proteins in this fraction showed several bands in the 23,000-85,000 Mr range. Radioimmunoassay, however, did not show cross-reactivity with antibodies to myelin basic protein. The functional role of this membrane in relation to mammalian myelin is discussed.     

Chemerin induced by Treponema pallidum predicted membrane protein Tp0965 mediates the activation of endothelial cell via MAPK signaling pathway

Chemerin, a chemoattractant protein, is involved in endothelial dysfunction and vascular inflammation in pathological conditions. In a recent study, we observed the upregulation of chemerin in endothelial cells following in vitro treatment with Treponema pallidum. Here, we investigated the role of chemerin in endothelial cells activation induced by the T. pallidum predicted membrane protein Tp0965. Following stimulation of human umbilical vein endothelial cells (HUVECs) with Tp0965, chemerin and its receptor chemerin receptor 23 (ChemR23) were upregulated, companied with elevated expression of Toll-like receptor 2. Furthermore, chemerin from HUVECs activated endothelial cells via chemerin/ChemR23 signaling in an autocrine/paracrine manner, characterized by upregulated expression of intercellular adhesion molecule 1, E-selectin, and matrix metalloproteinase-2. Activation of endothelial cells depended on the mitogen-activated protein kinase signaling pathway. In addition, Tp0965-induced chemerin promoted THP-1-derived macrophages migration to endothelial cells, also via the chemerin/ChemR23 pathway. The RhoA/ROCK signaling pathway was also involved in THP-1-derived macrophages migration in response to chemerin/ChemR23. Our results highlight the role of Tp0965-induced chemerin in endothelial cells dysfunction, which contributes to the immunopathogenesis of vascular inflammation of syphilis.