成骨细胞表面不同神经肽受体的表达

背景：大量研究表明神经因素可调节骨代谢,迄今为止已发现5种神经肽参与骨代谢过程。 目的：观察正常人成骨细胞表面不同神经肽受体的表达。 方法：分别以降钙素基因相关肽、酪氨酸羟化酶、P物质、神经肽Y的单克隆抗体进行免疫组化染色,观察各种肽类受体在成骨细胞表面的表达情况。另外,利用计算机图像分析系统对染色灰度进行半定量分析。 结果与结论：正常人成骨细胞表面有神经肽Y、P物质、酪氨酸羟化酶、降钙素基因相关肽受体表达,这些因子可以通过与相应的受体结合影响细胞生物学特性。不同因子免疫组化染色的灰度值由小到大依次为神经肽Y、降钙素基因相关肽、酪氨酸羟化酶、P物质,神经肽是成骨细胞活性的重要调节因子。     

降钙素基因相关肽神经生长因子与失神经支配兔骨折愈合

背景：骨折不愈合严重影响患者生活质量,神经生长因子用于骨不连的防治是重建外科领域研究的重点和方向。 目的：观察神经生长因子降钙素基因相关肽对失神经支配兔骨折愈合的影响。 方法：构建大白兔失神经支配腓骨骨折模型后,实验组骨折端局部注射降钙素基因相关肽10 μg,每2 d一次;对照组骨折端局部注射等量生理盐水。术后2,4,6周分别测定静脉血中肾上腺素和去甲肾上腺素的水平,并进行生物力学和组织学分析。 结果与结论：术后两组血清肾上腺素和去甲肾上腺素水平均有显著增高,在术后第4周达到最高峰,比术前高出1倍以上,第6周时出现下降,但仍然显著高于术前;术后2,4,6周,实验组肾上腺素和去甲肾上腺素血清水平较对照组显著增高,差异具有显著性意义(P < 0.05~0.01)。在三点弯曲实验中,实验组骨痂的抗弯强度明显高于对照组(P < 0.05~0.001);术后第6周时苏木精-伊红染色可见实验组骨痂中的透明软骨细胞已被成骨细胞替代,对照组骨痂中的软骨细胞仍没有完全成骨细胞化。提示神经生长因子降钙素基因相关肽对失神经支配兔骨折愈合具有明显的促进作用。 关键词：神经生长因子;降钙素基因相关肽;骨折愈合;生物力学;生物化学     

骨折愈合过程中降钙素基因相关肽表达与脑损伤的影响

背景：临床观察及实验研究发现合并中枢神经损伤的骨折愈合加速,但其具体机制尚未明确。 目的：观察股骨骨折合并脑损伤大鼠骨痂中降钙素基因相关肽及其mRNA的表达变化,探讨脑损伤对骨折愈合的影响及作用机制。 设计、时间及地点：随机对照动物实验,于2007-01/10在华北煤炭医学院骨科实验室完成。 材料：健康12周龄雌性SD大鼠64只,建立大鼠开放骨折模型。 方法：骨折造模后64只SD大鼠随机数字法分为骨折合并脑损伤组和单纯骨折组,每组32只,骨折合并脑损伤组接着制备脑损伤模型。造模后7,14,21,28 d分批麻醉并处死动物,苏木精-伊红染色观察骨折愈合情况,免疫组织化学染色及原位杂交检测降钙素基因相关肽及其mRNA的表达变化。 主要观察指标：①造模后28 d大鼠右侧股骨X射线平片表现。②造模后不同时间点两组大鼠骨痂苏木精-伊红染色、免疫组织化学染色及原位杂交结果。 结果：64只SD大鼠均进入结果分析。①X射线平片显示与单纯骨折组相比,骨折合并脑损伤组骨折端骨痂形成早,骨痂量多。②苏木精-伊红染色示单纯骨折组呈典型骨折愈合过程,而骨折合并脑损伤组骨痂形成及改造提前,骨折愈合加速。免疫组织化学染色显示骨折愈合过程中内皮细胞、骨祖细胞、软骨细胞及成骨细胞表达降钙素基因相关肽。骨折合并脑损伤组造模后各时间点阳性细胞数均高于单纯骨折组,差异有显著性意义(P < 0.05)。原位杂交检测示骨折合并脑损伤组造模后7,14,21 d表达降钙素基因相关肽mRNA的成骨细胞数均高于单纯骨折组,差异有显著性意义(P < 0.05)。 结论：脑损伤对骨折愈合有促进作用,可能与合并脑损伤后降钙素基因相关肽及其mRNA表达水平升高有关。     

pcDNA3.1-成骨生长肽真核表达载体在骨髓基质干细胞中的表达**

背景：成骨生长肽具有明显的促进成骨细胞增殖、分化、成熟的作用。 目的：观察成骨生长肽基因转染兔骨髓基质干细胞后的表达及表达产物对骨髓基质干细胞向成骨细胞分化的影响。 方法：构建重组真核表达载体pcDNA3.1-成骨生长肽,并在脂质体介导下,将其导入兔骨髓基质干细胞。通过G418筛选获得阳性克隆。RT-PCR方法检测成骨生长肽基因在骨髓基质干细胞内的表达,并观察转染pcDNA3.1-成骨生长肽后骨髓基质干细胞向成骨细胞分化的情况。 结果与结论：实验成功构建了真核表达载体pcDNA3.1-成骨生长肽,转染pcDNA3.1-成骨生长肽的骨髓基质干细胞可见成骨生长肽mRNA的表达,同时羟脯氨酸的分泌水平增加,碱性磷酸酶活性增高。证实经pcDNA3.1-成骨生长肽转染的兔骨髓基质干细胞不仅可以表达成骨生长肽,而且具有向成骨细胞分化的特性。     

降钙素基因相关肽与偏头痛

降钙素基因相关肽(CGRP)是一种广泛存在于中枢及周围神经系统的神经肽。多项试验证实其在偏头痛发作中发挥着舒张血管、介导神经源性炎症、调节痛觉感受等作用。近年来大量Ⅱ、Ⅲ期临床试验结果显示,针对降钙素基因相关肽的药物在偏头痛的急性期治疗和预防治疗中均可产生良好疗效,这或许可以彻底改变偏头痛的药物治疗选择。本文即通过总结国内外相关文献,讨论降钙素基因相关肽的结构分布,其在偏头痛发作过程中的作用及其相关药物的研发。     

降钙素基因相关肽诱导脂肪干细胞向成骨细胞的分化

背景：已证实降钙素基因相关肽可促进成骨细胞的增殖与分化，并加速骨折的愈合、促进异位骨化的形成，但其是否具有促使脂肪干细胞向成骨细胞定向分化的作用作者未查到相关报道。 目的：探讨降钙素基因相关肽在体外定向诱导脂肪干细胞向成骨细胞增殖分化的可行性。 设计、时间及地点：细胞学体外观察，基因及蛋白质学检测，于2006-10/2007-08在武汉大学医学院中心实验室和三峡大学医学院病理实验室完成。 材料：清洁级4月龄健康新西兰大耳白兔2只。 方法：密度梯度离心+贴壁法体外分离培养兔脂肪干细胞，传至第3代分为2组：对照组加入含10 mmol/Lβ-甘油磷酸钠、50 mg/L抗坏血酸、1×10-8 mol/L地塞米松、体积分数为0.15的胎牛血清的RPMI 1640骨诱导培养基，实验组在此基础上加入1 μg/L降钙素基因相关肽进行诱导培养。 主要观察指标：细胞形态学变化，免疫组织化学染色测定细胞碱性磷酸酶活性，四环素标记法检测矿化结节的形成，RT-PCR和Western blot法检测成骨细胞标志性蛋白I型胶原、骨钙素的表达。 结果：实验组脂肪干细胞经成骨诱导培养后，形态规则、多角型细胞增多，细胞倍增时间明显短于对照组。随诱导时间的延长，实验组细胞碱性磷酸酶活性呈增加趋势，诱导7，10，14 d细胞碱性磷酸酶活性均显著高于对照组(t=13.26，P < 0.01)。诱导21 d与对照组比较，实验组形成的金黄色圆形矿化结节数量增多，结节增大。诱导7 d，14 d实验组I型胶原及骨钙素mRNA、蛋白水平的表达均强于对照组。 结论：在体外降钙素基因相关肽能诱导并促进兔脂肪干细胞向成骨细胞方向分化。     

不同质量浓度神经肽培养正常人成骨细胞的增殖活性

背景：大量的研究表明神经因素可调节骨代谢,迄今为止已发现5种神经肽参与骨代谢过程。 目的：进一步验证神经肽类物质对培养的正常人成骨细胞主要生物学行为的影响。 方法：分别以0.02,0.1,1 mg/L 3种质量浓度的降钙素基因相关肽、血管活性肠肽、物质P、神经肽Y、去甲肾上腺素、骨形态发生蛋白作用于成骨细胞,通过噻唑蓝法比较不同因子的效应、同一因子不同质量浓度的作用以及骨形态发生蛋白与其他5种因子复合后的效应。 结果与结论：5种神经肽类物质及骨形态发生蛋白均能促进成骨细胞的增殖,其中神经肽Y效应最强。并且除了骨形态发生蛋白外,其余5种因子的效应均与剂量成反比。结果提示,5种神经肽类因子及骨形态发生蛋白均能不同程度地促进成骨细胞活性,这从一个侧面对某些肽类物质促进成骨的现象做出了解释。     

降钙素对大鼠颅骨成骨细胞调控作用的体外观察

背景：降钙素是强有力的破骨细胞抑制剂,可直接、快速而广泛地抑制骨吸收,近年来有学者报道其有促进骨折愈合的功能,推测降钙素对成骨细胞也有直接的作用。 目的：体外观察降钙素对大鼠成骨细胞的药理作用,分析其是否通过细胞外信号调节激酶信号通路产生。 设计、时间及地点：分组对照观察,于2007-06/2008-05在南京医科大学药理学实验室完成。 材料：选用新生SD大鼠,分离培养颅骨成骨细胞。 方法：取第2代成骨细胞进行分组实验：0.01 μg/L降钙素组、0.1 μg/L降钙素组、1 μg/L降钙素组分别加入不同剂量降钙素进行干预,U0126＋1 μg/L降钙素组提前30 min加入100 μmol/L的细胞外信号调节激酶抑制剂U0126,并设空白对照组。 主要观察指标：通过四甲基偶氮唑盐比色法、对硝基苯磷酸盐法和钙结节茜素红染色法分别检测降钙素对成骨细胞的增殖、分化、矿化能力的影响;应用反转录-聚合酶链反应技术检测促骨形成关键基因核心结合因子a1 mRNA的表达情况;应用Western Blotting技术检测磷酸化细胞外信号调节激酶1/2蛋白表达情况。 结果：加入0.01,0.1,1 μg/L的降钙素干预后,成骨细胞的增殖、分化、矿化能力以及核心结合因子a1 mRNA的表达均随降钙素剂量增加而增强,且0.1,1 μg/L组与空白对照组比较差异具有显著意义（P < 0.05~0.01）;此外降钙素促进了磷酸化细胞外信号调节激酶1/2蛋白的表达(P < 0.05)。U0126可阻断以上所有效应（P < 0.05~0.01）。 结论：降钙素可能通过细胞外信号调节激酶信号通路调控促骨形成关键基因核心结合因子a1 mRNA的表达,进而促进成骨细胞的增殖、分化、矿化能力。     

脑损伤并胫骨骨折大鼠骨痂中神经肽的分布及意义*☆

目的: 研究证明，含有P物质、降钙素基因相关肽、血管活性肠肽、神经肽Y和酪氨酸羟化酶等神经肽的肽能神经共同存在于骨组织中，主要分布于骨代谢活跃的区域，表明这些肽能神经与骨的生长、发育密切相关。观察脑损伤后大鼠胫骨骨痂中神经肽的表达。 方法：实验于2007-02/05在广西医科大学实验动物中心完成。①实验分组：雄性Wistar大鼠130只，体质量450~550 g，随机数字表法分为单纯骨折组（n =60），脑损伤合并骨折组（n =60），正常对照组（n =10）。②实验方法：麻醉后显露大鼠右颅顶骨，中线旁2 mm 处开直径5 mm 骨窗，液压打击致中度脑损伤，并制备大鼠胫骨骨折模型，其中单纯骨折组头部只做颅骨开窗，正常对照组不做任何处理。③实验评估：术后3，7，14，21，28，35 d 苏木精-伊红染色和神经肽免疫组织化学染色观察神经肽在大鼠胫骨中的分布及胫骨骨折骨痂的连续性及骨折愈合情况。计算机X射线摄像仪（CR）摄片测定术后14，21，28 d 脑损伤合并骨折组及单纯骨折组骨痂面积大小。 结果：纳入大鼠130只，均进入结果分析。①脑损伤合并骨折组早期形成大量纤维骨痂和软骨骨痂，骨痂中神经肽免疫阳性神经纤维较多，明显增厚的骨膜内层骨祖细胞、幼稚的软骨细胞胞质内降钙素基因相关肽、P物质、血管活性肠肽、酪氨酸羟化酶、神经肽Y强阳性表达。②脑损伤合并骨折组14 d 纤维骨痂中的软骨细胞团增大，骨膜下软骨细胞层增厚；21 d 小梁骨明显增厚，软骨岛增大；28 d 仍可见大量的纤维骨痂和软骨骨痂，软骨细胞团周边有少量结构稀疏的编织骨形成。单纯骨折组骨膜反应轻，纤维骨痂量少，骨内成骨和软骨内成骨并存，以前者为主，骨折愈合过程明显晚于脑损伤合并骨折组。③14，21 d 脑损伤合并骨折组骨痂面积较单纯骨折组大（P < 0.01）；21，28 d 脑损伤合并骨折组骨痂面积变化明显快于单纯骨折组，提示骨痂塑性快（P < 0.01）。CR摄片发现，各骨折组大鼠骨折端均未发现不愈合现象，单纯骨折组骨折线清晰，骨痂量较少；脑损伤合并骨折组骨性愈合较好，骨痂量较多，骨折线模糊。 结论：正常大鼠骨生长活跃区有丰富的肽能神经支配。脑损伤后骨痂中神经肽有显著改变，并引起骨痂量和质的改变，骨折愈合加速。     

基因芯片分析成骨生长肽对OPG-/-小鼠骨髓间充质干细胞的作用

背景：合成成骨生长肽在体外可刺激骨髓间充质干细胞增殖和向成骨细胞分化,体内可增加骨密度改善骨质疏松,但具体作用机制尚未明确。 目的：应用小鼠全基因组芯片筛查合成成骨生长肽作用下OPG-/-小鼠骨髓间充质干细胞的差异表达基因,探索成骨生长肽作用下可能影响到的基因与信号传导通路。 方法：应用上海伯豪生物技术有限公司提供的小鼠全基因组Oligo芯片,筛选成骨生长肽干预组与空白对照组OPG-/-小鼠骨髓间充质干细胞差异表达基因,实时定量PCR分析验证部分与增殖分化相关的差异表达基因,并结合聚类分析及通路分析来探索成骨生长肽的作用机制。 结果与结论：芯片结果显示,成骨生长肽作用后使346条基因表达下调,121条基因表达上调。PCR验证结果与芯片结果相符。经BioCarta通路分析,涉及6条通路蛋白;经KEGG通路分析,涉及12条通路。成骨生长肽对OPG-/-小鼠骨髓间充质干细胞的作用涉及多条信号传导通路,其中MAPK信号传导通路可能对其促增殖起着至关重要作用。     

Decreased CGRP, but preserved Trk A immunoreactivity in nerve fibres in inflamed human superficial temporal arteries

The peptidergic sensory innervation of cranial blood vessels may play an important part in vascular head pain. The neuropeptides calcitonin gene-related peptide (CGRP) and substance P in sensory fibres are dependent on nerve growth factor (NGF) produced by the blood vessels, and when released from nerve terminals mediate neurogenic inflammation. NGF is increased in inflamed tissues, and acts via its high affinity receptor trk A on nociceptor fibres to produce hyperalgesia. CGRP and trk A immunoreactive nerve fibres have therefore been studied, for the first time, in inflamed (n=7) and non-inflamed (n=10) temporal arteries biopsied from patients with headache and suspected giant cell arteritis. CGRP immunoreactivity was markedly decreased to absent in adventitial nerve fibres in inflamed regions of vessels, which may reflect secretion from nerve terminals, as CGRP immunoreactivity could still be seen in nerve trunks in periadventitial tissue. Trk A immunoreactive nerve fibres were found in a similar distribution to CGRP containing nerve fibres in non-inflamed vessels, and the trk A immunoreactivity was virtually unchanged in inflamed vessels. The evidence supports a role for NGF related mechanisms in inflammatory vascular head pain. Anti-NGF or anti-trk A agents may represent novel analgesics in this condition.     

Understanding migraine: Potential role of neurogenic inflammation

Neurogenic inflammation, a well-defined pathophysiologial process is characterized by the release of potent vasoactive neuropeptides, predominantly calcitonin gene-related peptide (CGRP), substance P (SP), and neurokinin A from activated peripheral nociceptive sensory nerve terminals (usually C and A delta-fibers). These peptides lead to a cascade of inflammatory tissue responses including arteriolar vasodilation, plasma protein extravasation, and degranulation of mast cells in their peripheral target tissue. Neurogenic inflammatory processes have long been implicated as a possible mechanism involved in the pathophysiology of various human diseases of the nervous system, respiratory system, gastrointestinal tract, urogenital tract, and skin. The recent development of several innovative experimental migraine models has provided evidence suggestive of the involvement of neuropeptides (SP, neurokinin A, and CGRP) in migraine headache. Antidromic stimulation of nociceptive fibers of the trigeminal nerve resulted in a neurogenic inflammatory response with marked increase in plasma protein extravasation from dural blood vessels by the release of various sensory neuropeptides. Several clinically effective abortive antimigraine medications, such as ergots and triptans, have been shown to attenuate the release of neuropeptide and neurogenic plasma protein extravasation. These findings provide support for the validity of using animal models to investigate mechanisms of neurogenic inflammation in migraine. These also further strengthen the notion of migraine being a neuroinflammatory disease. In the clinical context, there is a paucity of knowledge and awareness among physicians regarding the role of neurogenic inflammation in migraine. Improved understanding of the molecular biology, pharmacology, and pathophysiology of neurogenic inflammation may provide the practitioner the context-specific feedback to identify the novel and most effective therapeutic approach to treatment. With this objective, the present review summarizes the evidence supporting the involvement of neurogenic inflammation and neuropeptides in the pathophysiology and pharmacology of migraine headache as well as its potential significance in better tailoring therapeutic interventions in migraine or other neurological disorders. In addition, we have briefly highlighted the pathophysiological role of neurogenic inflammation in various other neurological disorders.     

Effects of insulin-like growth factor-1 on expression of sensory neuropeptides in cultured dorsal root ganglion neurons in the absence or presence of glutamate

Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor and plays an important role in promoting axonal growth from dorsal root ganglion (DRG) neurons. Whether IGF-1 could influence expression of sensory neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) of the cultured DRG neurons with excitotoxicity induced by glutamate (Glu) remains unknown. In the present study, primary cultured DRG neurons were used to determine the effects of IGF-1 on expression of SP and CGRP of the neurons with Glu-induced excitotoxicity. The DRG neurons were dissociated and cultured for 48 hr and then exposed to Glu (0.2 mmol/L), IGF-1 (20 nmol/L), and Glu (0.2 mmol/L) plus IGF-1 (20 nmol/L) for additional 12 hr. The DRG neurons were continuously exposed to growth media as control. After that, all the above cultured DRG neurons were processed for detecting SP and CGRP expression by Western blot analysis. The expression of SP and CGRP increased significantly in primary cultured DRG neurons in the presence of IGF-1. The ability of IGF-1 on SP and CGRP expression may play a role in neurogenic inflammation or nociception.     

Inhibition of lipopolysaccharide-induced microglia activation by calcitonin gene related peptide and adrenomedullin

Calcitonin gene related peptide (CGRP) and adrenomedullin are potent biologically active peptides that have been proposed to play an important role in vascular and inflammatory diseases. Their function in the central nervous system is still unclear since they have been proposed as either pro-inflammatory or neuroprotective factors. We investigated the effects of the two peptides on astrocytes and microglia, cells of the central nervous system that exert a strong modulatory activity in the neuroinflammatory processes. In particular, we studied the ability of CGRP and adrenomedullin to modulate microglia activation, i.e. its competence of producing and releasing pro-inflammatory cytokines/chemokines that are known to play a crucial role in neuroinflammation. In this work we show that the two neuropeptides exert a potent inhibitory effect on lipopolysaccharide-induced microglia activation in vitro, with strong inhibition of the release of pro-inflammatory mediators (such as NO, cytokines and chemokines). Both CGRP and adrenomedullin are known to promote cAMP elevation, this second messenger cannot fully account for the observed inhibitory effects, thereby suggesting that other signaling pathways are involved. Interestingly, the inhibitory effect of CGRP and adrenomedullin appears to be stimulus specific, since direct activation with pro-inflammatory cytokines was not affected.Our findings clarify aspects of microglia activation, and contribute to the comprehension of the switch from reparative to detrimental function that occurs when glia is exposed to different conditions. Moreover, they draw the attention to potential targets for novel pharmacological intervention in pathologies characterized by glia activation and neuroinflammation.     

Intrathecal PKA-selective siRNA treatment blocks sustained morphine-mediated pain sensitization and antinociceptive tolerance in rats

Sustained morphine treatment has been shown to produce paradoxical pain sensitization (opioid-induced hyperalgesia) and also causes increase in spinal pain neurotransmitter, such as calcitonin gene related peptide (CGRP), concentration in experimental animals. Studies have also shown that cyclic adenosine-monophosphate (cAMP)-dependent protein kinase (PKA) plays a major role in the regulation of presynaptic neurotransmitter (such as CGRP and substance P) synthesis and release. We have previously shown that in cultured primary sensory dorsal root ganglion (DRG) neurons sustained in vitro opioid agonist treatment upregulates cAMP levels (adenylyl cyclase (AC) superactivation) and augments basal and capsaicin evoked CGRP release in a PKA dependent manner. In the present study, we investigated the in vivo role of PKA in sustained morphine-mediated pain sensitization. Our data indicate that selective knock-down of spinal PKA activity by intrathecal (i.th.) pretreatment of rats with a PKA-selective small interference RNA (siRNA) mixture significantly attenuates sustained morphine-mediated augmentation of spinal CGRP immunoreactivity, thermal hyperalgesia, mechanical allodynia and antinociceptive tolerance. The present findings indicate that sustained morphine-mediated activation of spinal cAMP/PKA-dependent signaling may play an important role in opioid induced hyperalgesia.     

Proinflammatory mediators and migraine pathogenesis: moving towards CGRP as a target for a novel therapeutic class

Migraine is a complex neurological disorder in which genetic and environmental factors interact. At present, frontline therapies in migraine's acute treatment include the use of NSAIDS and triptans. Restrictions in the use of frontline drugs for migraine treatment and evidence concerning CGRP's key role led research towards new pathways involved in migraine pathophysiology. CGRP is a strong vasodilatory neuropeptide released from activated trigeminal sensory nerves. The development of CGRP antagonists has also been driven by the fact that triptans are vasoconstrictive and cannot be used in patients with vascular risk factors. BIBN4096 (olcegepant) is the first CGRP antagonist for the treatment of migraine which has been tested in clinical trials, but its principal limitation is that BIBN4096 presents low oral bioavailability and has only been tested through intravenous formulation. The first oral nonpeptide CGRP antagonist, MK-0974 (telcagepant), has recently been shown to be highly effective in the treatment of migraine attacks. This development can be considered the most important pharmacological breakthrough for migraine treatment since the introduction of sumatriptan in the early 1990s. These results are important since they confirm the current pathophysiological concept of migraine. The future introduction of CGRP antagonists in clinical practice could represent a progress for migraine therapy.     

Nerve Growth Factor Treatment Increases Stimulus-evoked Release of Sensory Neuropeptides in the Rat Spinal Cord

In the adult rat, nerve growth factor (NGF) upregulates the nociceptive peptide substance P (SP) and calcitonin gene-related peptide (CGRP) in neuronal cell bodies of C fibres but the effects of NGF on release of these neuropeptides from the central afferent terminals have not been reported. Thus, this study compared rats treated with six doses of NGF over 2 weeks with controls and measured the release of the neuropeptides, SP and CGRP from the dorsum of the lumbar spinal cord in vitro. NGF (1.0 mg/kg s.c.) greatly increased basal and stimulus-evoked SP and CGRP release; at 0.1 mg/kg, NGF did not affect SP release but significantly increased CGRP basal outflow and evoked release. In a different set of experiments, topical application of NGF (100 ng/ml) to cords from naive rats did not increase stimulus-evoked release of SP or CGRP. These findings show marked stimulation by NGF treatment in vivo of release of sensory neuropeptides during stimulation of dorsal roots, albeit at relatively large doses of the neurotrophin.     

Changes in tracheo-bronchial sensory neuropeptide receptor gene expression pattern in rats with cisplatin-induced sensory neuropathy

An attenuated neurogenic broncho-constriction underpinned by a decrease in sensory neuropeptide release has been shown to be characteristic of cisplatin-induced neuropathy. The present work was to explore if beyond neuropeptide release, cisplatin at a treatment schedule attaining sensory neuropathy, produced changes in the expression of the receptors of sensory neuropeptides such as somatostatin, calcitonin gene-related peptide (CGRP) and substance P (SP) in bronchial tissue of the rat. Twenty-four Wistar rats were divided into three groups. The animals in the "Treatment groups 1 and 2" were given cisplatin (1.5mgkg(-1)) and mannitol (75mgkg(-1)) over 5 days. The rats in the "Control" group were given mannitol+isotonic saline. Four animals from each group were used to study the expression pattern of the neuropeptide receptors in bronchial tissue. The levels of somatostatin receptor 4 (SSTR 4), neurokinin 1 (NK1), neurokinin 2 (NK2) and CGRP receptor expression were examined by quantitative real time polymerase chain reaction (RT-PCR) method, 11 and 22 days after the last cisplatin/vehicle dose. The cisplatin treatment significantly increased plasma somatostatin immunoreactivity and the expression of SSTR4 receptor detected both on the 11th and 22nd post-treatment days with no change in either CGRP, NK1, and NK2 receptor gene expression or plasma CGRP and substance P levels. We conclude that cisplatin neuropathy is accompanied by an increase in plasma somatostatin immunoreactivity with an increase in SSTR4 expression in rats.     

Marked depletion of dorsal spinal cord substance P and calcitonin gene-related peptide with intact skin flare responses in multiple system atrophy.

In view of the presence of neuropeptides in spinal cord autonomic pathways, their regional concentration was studied in post mortem thoracic cord from four cases of multiple system atrophy with progressive autonomic failure (MSA). A marked depletion was observed of substance P, its related peptide substance K, and of calcitonin gene-related peptide (CGRP), particularly in dorsal regions where peptide-containing sensory fibres terminate. As substance P and CGRP in primary sensory fibres are considered mediators of skin flares in Lewis' triple response, histamine-induced skin flares were measured in 12 MSA patients and were found to be preserved. These results provide a new key to the classification and aetiology of autonomic and multiple system degenerations, as well as a model to study the role of sensory neuropeptides in man.