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1.
Substance P: does it produce analgesia or hyperalgesia?   总被引:2,自引:0,他引:2  
In the hot plate test, substance P given intravenously at doses of 5 x 10-5 and 5 x 10-4 gram per kilogram caused analgesia, while lower doses caused hyperalgesia. The influence of substance P on nociception depended on the individual mouse's sensitivity to pain (control response latency). Analgesia was produced by substance P administered to mice with high sensitivity to thermic stimulation, whereas hyperalgesia occurred in mice whose control latencies were longer than normal. This result is interpreted as an indication that substance P is capable of normalizing responsiveness to pain and could be classified as a regulatory peptide.  相似文献   

2.
Inflammation and trauma lead to enhanced pain sensitivity (hyperalgesia), which is in part due to altered sensory processing in the spinal cord. The synaptic hypothesis of hyperalgesia, which postulates that hyperalgesia is induced by the activity-dependent long-term potentiation (LTP) in the spinal cord, has been challenged, because in previous studies of pain pathways, LTP was experimentally induced by nerve stimulation at high frequencies ( approximately 100 hertz). This does not, however, resemble the real low-frequency afferent barrage that occurs during inflammation. We identified a synaptic amplifier at the origin of an ascending pain pathway that is switched-on by low-level activity in nociceptive nerve fibers. This model integrates known signal transduction pathways of hyperalgesia without contradiction.  相似文献   

3.
Painful stimuli activate nociceptive C fibers and induce synaptic long-term potentiation (LTP) at their spinal terminals. LTP at C-fiber synapses represents a cellular model for pain amplification (hyperalgesia) and for a memory trace of pain. μ-Opioid receptor agonists exert a powerful but reversible depression at C-fiber synapses that renders the continuous application of low opioid doses the gold standard in pain therapy. We discovered that brief application of a high opioid dose reversed various forms of activity-dependent LTP at C-fiber synapses. Depotentiation involved Ca(2+)-dependent signaling and normalization of the phosphorylation state of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. This also reversed hyperalgesia in behaving animals. Opioids thus not only temporarily dampen pain but may also erase a spinal memory trace of pain.  相似文献   

4.
Conformational data for macromolecules in the gas phase have been obtained by the coupling of a matrix-assisted laser desorption ion source to an ion chromatograph. A series of polyethylene glycol (PEG) polymers "cationized" (converted to a cation) by sodium ions (Na(+)PEG9 to Na(+)PEG19) and a protonated neurotransmitter protein, bradykinin, were studied. Mobilities of Na(+)PEG9 to Na(+)PEG19 are reported. Detailed modeling of Na(+)PEG9 with molecular mechanics methods indicates that the lowest energy structure has the Na(+) ion "solvated" by the polymer chain with seven oxygen atoms as nearest neighbors. The agreement between the model and experiment is within 1 percent for Na(+)PEG9, Na(+)PEG13, and Na(+)PEG17, giving strong support to both the method and the deduced structures. Similar agreement was obtained in initial studies that modeled experimental data for arginine-protonated bradykinin.  相似文献   

5.
Kim D  Park D  Choi S  Lee S  Sun M  Kim C  Shin HS 《Science (New York, N.Y.)》2003,302(5642):117-119
Sensations from viscera, like fullness, easily become painful if the stimulus persists. Mice lacking alpha1G T-type Ca2+ channels show hyperalgesia to visceral pain. Thalamic infusion of a T-type blocker induced similar hyperalgesia in wild-type mice. In response to visceral pain, the ventroposterolateral thalamic neurons evokeda surge of single spikes, which then slowly decayed as T type-dependent burst spikes gradually increased. In alpha1G-deficient neurons, the single-spike response persisted without burst spikes. These results indicate that T-type Ca2+ channels underlie an antinociceptive mechanism operating in the thalamus andsupport the idea that burst firing plays a critical role in sensory gating in the thalamus.  相似文献   

6.
Concentrations of butylated hydroxyanisole as low as 8 x 10(-9) mole per liter can inhibit detectably the contraction of smooth muscle elicited by bradykinin. The mechanism of the inhibitory effect of this food grade anti-oxidant is apparently complex, and the effect is only partially reversible.  相似文献   

7.
研究表达的丙型肝炎病毒(HCV)NS4B对Hep3B细胞非折叠蛋白质反应的影响。NS4B重组真核表达质粒pcDNA3.1(-)NS4B通过脂质体转染Hep3B细胞,G418筛选和Western blot鉴定稳定转染细胞;RT-PCR检测稳定转染细胞内XBP1 mRNA剪接,Western blot鉴定ATF6蛋白切割,荧光素酶试验检测稳定转染细胞内GRP78和XBP1启动子活性。G418筛选和Western Blot鉴定证实获得稳定表达NS4B的Hep3B细胞;在该细胞内,XBP1 mRNA剪接、ATF6切割、XBP1和Grp78启动子激活均被检测到。NS4B在Hep3B的稳定表达诱导了非折叠蛋白质反应。  相似文献   

8.
The cumulative effects of a repetitive stress induced by anticipation of pain (noxious foot shock) were studied on the threshold of a nociceptive flexion reflex of the lower limb. The threshold of the nociceptive reflex progressively increased with the repetition of the stress. This effect was reversed by naloxone, which even produced hyperalgesia, since a rapid and significant decrease in this threshold, below the initial values, was noted. Tha data provide evidence for involvement of endogenous opioids in the phenomenon of stress-induced analgesia in normal man.  相似文献   

9.
从小麦叶片和穗部分离、筛选出对小麦赤霉病菌(Fusariumgraminearum)有很强拮抗作用的芽孢杆菌菌株B4、B6,经室内离体叶、穗防效测定和田间小区防效试验,二菌株对小麦赤霉病有较好防效,与清水对照相比,相对防效达684%、689%,接近多菌灵的防效(704%)。对B4、B6菌株进行形态和生理生化特征的分类鉴定,二菌株均为枯草芽孢菌(Bacilussubtilis)  相似文献   

10.
鸡粪高效除臭菌的组合筛选研究   总被引:5,自引:0,他引:5  
以正在腐熟的鸡粪、长期堆放鸡粪的土壤和污水沟中的污水为样本,从中分离出132株细菌,经过初筛、复筛,得到除臭效果较好的反硫化细菌8株、硫化细菌4株和亚硝化细菌4株。通过正交设计,研究菌株的组合除臭效果。结果表明:菌株除臭效果主要作用在前期。在不考虑交互作用时,处理C4B3A4的除NH3效果较对照降低55.5%,处理B1C3A2的除H2S效果较对照降低40.0%。在考虑交互作用时,处理C4B3A3的除NH3效果较好,NH3释放量较处理C4B3A4降低14.9%;2个处理的H2S释放量分别较对照减少45.2%和46.9%,但这2个处理效果差异不明显。  相似文献   

11.
利用半定量逆转录-聚合酶链式反应(RT-PCR)技术,测定新吉细毛羊皮肤组织中 BⅢB4基因mRNA表达水平,以18SrRNA为内标,分析相对表达量及其与羊毛细度的关系.通过探讨和优化PCR体系中退火温度、MgCl2浓度和循环次数等参数,建立了检测羊毛细度相关基因mRNA表达的半定量RT-PCR体系.用Independent Samples T Test分析BⅢB4 PCR产物与18SrRNA PCR产物电泳后的灰度比值,可知BⅢB4基因mRNA表达量对羊毛细度的影响.  相似文献   

12.
目的构建人B7-H4慢病毒表达载体。方法将RT-PCR扩增的B7-H4基因全长编码序列克隆到慢病毒转移载体,通过脂质体转染293细胞,包装成人B7-H4慢病毒颗粒。RT-PCR、流式细胞术和Western blot鉴定B7-H4在重组慢病毒感染293细胞中表达,50%组织培养感染剂量法(TCID50法)检测重组慢病毒滴度。结果成功构建了pMD18-T-hB7-H4质粒和pEZ-Lv105-hB7-H4质粒。基因测序分析证实人B7-H4编码序列成功整合到质粒载体。TCID50法测定Lenti-hB7-9H4慢病毒滴度为1.7×10^9 copies/mL。RT-PCR、流式细胞术和Western blot证实Lenti-hB7-H4慢病毒转染细胞后可有效表达人B7-H4 mRNA和蛋白质。结论成功构建了表达人B7-H4的慢病毒颗粒。  相似文献   

13.
Bradykinin infusion causes an increase in cardiac output in rats whether the autonomic nervous system is blocked or not. After autonomic blockade, bradykinin causes a lesser decrease in the total peripheral resistance but a greater increase in cardiac output, resulting in an elevation of arterial pressure. The increase in cardiac output is caused by a small increase in heart rate and a substantial increase in stroke volume. The fact that these increases are observed after autonomic blockade suggests that bradykinin increases cardiac output by direct stimulation of the heart.  相似文献   

14.
本试验采用二因子交叉设计方法研究了不同能量、蛋白质水平日粮对本地生长肉犬采食量、生长速度和饲料转化率以及经济效益的影响,同时比较了不同生长阶段生产性能的差异,由此筛选不同生长阶段的最佳营养需要量。结果表明:全期平均日增重B1最高,与B4差异极显著(P<0.01),与B3差异显著(P<0.05),比B2差异不显著;饲料转化率亦以B1最高,比B2、B3、B4分别提高14.2%、23.1%和39.2%;每千克增重饲料成本是B4>B3>B2>B1。两因子测定结果最佳组合为A1B1、A1B2和A3B1,其次为A2B2、A2B1和A3B3。  相似文献   

15.
【目的】探究贝莱斯芽孢杆菌B4-7联合水稻秸秆生物炭对烟草青枯病的防治效果,明确水稻秸秆生物炭对菌株B4-7防治烟草青枯病的增强作用,为进一步研发烟草青枯病的生防产品提供参考。【方法】采用平板培养法测定不同含量水稻秸秆生物炭(1%C、2%C、3%C和4%C)对烟草青枯病菌生长的抑制作用、吸附作用及运动性影响;通过盆栽试验测定菌株B4-7联合2%和5%水稻秸秆生物炭(B4-7+2%C、B4-7+5%C)对烟草的促生长作用及对烟草青枯病的防治作用。【结果】不同浓度的水稻秸秆生物炭对烟草青枯病菌均具有一定的生长抑制作用、吸附作用及运动性影响,与对照相比,1%C、2%C、3%C和4%C处理每培养皿中的青枯菌数量分别减少8.07%、37.01%、53.74%和69.29%,青枯菌的运动性分别减少28.57%、35.71%、42.86%和48.57%,对烟草青枯菌的吸附率分别为24.18%、42.42%、64.55%和81.97%。B4-7+5%C处理与对照相比,烟草株高、叶数、最大叶长和最大叶宽分别增加209.36%、27.98%、254.51%和185.09%;B4-7+5%C处理与B4-7单独处理相比,烟草株高和叶数均存在显著差异(P<0.05,下同),分别增加77.52%和11.74%。B4-7+5%C处理与对照相比,烟草青枯病发病率和病情指数分别显著减少81.33%和80.61%;B4-7+5%C处理与B4-7单独处理相比,烟草青枯病发病率和病情指数分别显著减少54.82%和45.29%,防治效果显著增加24.85%。【结论】水稻秸秆生物炭能增强生防细菌B4-7对烟草青枯病的防治效果,菌株B4-7联合5%水稻秸秆生物炭是烟草青枯病综合防控的一种有效措施,具有较大的应用前景,值得进一步推广和应用。  相似文献   

16.
用mRNA差别显示技术对白菜核雄性不育两用系中不育株群与可育株群花蕾总RNA进行了比较分析.在6种反转录模板和20种差异随机引物共120种组合的选择扩增中共回收了18个cDNA差异片段,对其中6个cDNA差异片段进行Northern验证,获得了一个白菜核雄性不育两用系可育株群并在花蕾中特异表达的阳性差异片段,简称为B0302-4.Northern验证结果表明它在不育株中的表达受到了明显的抑制,其长度为463 bp.经GenBank BLAST查询,它与拟南芥第一条染色体上编码细胞色素P450的基因CYP86C4核苷酸序列有84.3%的同源性.  相似文献   

17.
Four isolates of Bacillus subtilis coded, B4, B7, B8 and B10 were examined as biocontrol agents for their abilities and antagonistic effect on the in vitro growth of certain phytopathogenic fungi of peanut, Rhizoctonia solani and Sclerotium rolfsii. Bacillus subtilis isolate B4(GenBank accession no. EF150884) was the highly effective one for inhibiting the fungal mycelial growth. Batch fermentation of B. subtilis isolate B4 was carried out and the maximum biomass achieved was 4.53 g L~(-1) at 11 h. Bacillus subtilis isolate B4 was formulated and evaluated as a biofungicide to reduce peanut soil-borne diseases under greenhouse and field conditions at the side of Rizolex-T(fungicide) as standard. Treatments by formulated plant growth-promoting rhizobacteria(PGPR) B. subtilis B4 and Rizolex-T in a soil infested with R. solani, S. rolfsii and mixture of them were more effective in decreasing percentage of damping-off, root and pod rot disease incidence(%) in greenhouse and open field environment during the two seasons 2015 and 2016. Treatments by PGPR gave highly dry weight and number of healthy pods compared to control of fungi treatment which was nearby to dry weights of healthy pods achieved by treatments by Rizolex-T in a soil infested with S. rolfsii, R. solani and mixture of them. Formulated PGPR B. subtilis B4 gave higher increasing of yield percentage than treatment by Rizolex-T in the two evaluated seasons 2015 and 2016. It can conclude that the produced bioforumlated agent was more efficient as fungicide when compared with the other chemical synthesized fungicides, safe for human and the environment and economy.  相似文献   

18.
基于2005年江苏省森林资源连续清查数据,采用蓄积量——生物量换算因子连续函数法计算杨树林生物量,对生物量与LandsatTM数据各波段的比值B1/B3、B2/B4 、B2×B3/B4、B7/B5 、B7/B5、(B4+ B5-B2)/(B4+B5+ B2)、B3/(B1+B2 +B3 +B4 +B5 +B7)、B3/B4及植被指数NDVI、RVI、TNDVI进行相关性分析,筛选杨树生物量遥感估算模型的相应因子;并应用逐步回归技术建立估算杨树生物量遥感模型,估算出2005年泗阳县杨树林总面积为29 768.6 hm2,总生物量约为1 786 771.2 t,平均生物量约为60.0 t/hm2.结果表明,在森林资源连续清查的数据基础上,利用遥感影像在县级区域尺度上对杨树森林生物量进行有效估算是完全可行的,其方法具有时间分辨率高的特点,使生物量估算在较大的时间和空间尺度上具备操作的可能性.  相似文献   

19.
当归专用肥配方筛选及肥效试验   总被引:2,自引:0,他引:2  
为筛选当归专用肥配方及最佳施肥量,通过田间试验的方法,对8个专用肥配方与常规施肥对当归成药期根部形态特征及根产量影响进行比较分析。结果表明,当归专用肥最优配方为B1和B4,各处理中,配方B1和B4对当归成药期根部形态特征芦头径、主身径和根长的形成具有较好的效果,能有效提高当归产量,分别较常规施肥平均增产18.09%和16.82%。当归的芦头径、主身径随着配方B1和B4施肥量的增加而增加,而施肥量对根长影响不大,适宜的施肥量可有效提高当归阿魏酸质量分数,较常规施肥提高0.058%和0.075%,可有效提高氮、磷的利用率。配方B1和B4适宜施肥量为900~1 050kg/hm2,在1 050kg/hm2施肥量条件下,配方B1产值及纯收益最高。  相似文献   

20.
Inflammation, trauma, or nerve injury may cause enduring hyperalgesia, an enhanced sensitivity to painful stimuli. Neurons in lamina I of the spinal dorsal horn that express the neurokinin 1 receptor for substance P mediate this abnormal pain sensitivity by an unknown cellular mechanism. We report that in these, but not in other nociceptive lamina I cells, neurokinin 1 receptor-activated signal transduction pathways and activation of low-threshold (T-type) voltage-gated calcium channels synergistically facilitate activity- and calcium-dependent long-term potentiation at synapses from nociceptive nerve fibers. Thereby, memory traces of painful events are retained.  相似文献   

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