大鼠肢体IRI后脊髓神经元Fos的表达

目的探讨脊髓神经元是否参与肢体缺血再灌注损伤（IRI）的发病过程以及有关神经元的分布特点。方法Wistar大鼠24只,随机分为4组,A：空白对照组;B：假手术对照组;C：单纯缺血组;D：缺血再灌注组。通过暂时阻断一侧髂总动脉和股动脉,建立肢体缺血再灌注损伤模型。采用免疫细胞化学ABC法,观察大鼠脊髓神经元原癌基因c—fos的表达和分布特点。结果大鼠肢体缺血4h,脊髓相应节段神经元Fos表达活跃。再灌注2h后,Fos表达更加活跃（P〈0．01）。并且Fos阳性神经元较集中分布于脊髓相应节段同侧后角及中央管周围。结论脊髓相应节段同侧神经元可能参与肢体IRI的发病过程,尤其是脊髓后角及中央管周围神经元可能具有更为重要的作用。     

Differential involvement of 3′, 5′-cyclic adenosine monophosphate-dependent protein kinase in regulation of Fos and tyrosine hydroxylase expression in the heart after naloxone induced morphine withdrawal

We previously demonstrated that morphine withdrawal induced hyperactivity of the heart by the activation of noradrenergic pathways innervating the left and right ventricle, as evaluated by noradrenaline (NA) turnover and Fos expression. We investigated whether cAMP-dependent protein kinase (PKA) plays a role in this process by estimating changes in PKA immunoreactivity and the influence of inhibitor of PKA on Fos protein expression, tyrosine hydroxylase (TH) immunoreactivity levels and NA turnover in the left and right ventricle. Dependence on morphine was induced by a 7-day s.c. implantation of morphine pellets. Morphine withdrawal was precipitated on day 8 by an injection of naloxone (5 mg/kg). When opioid withdrawal was precipitated, an increase in PKA immunoreactivity and phospho-CREB (cyclic AMP response element protein) levels were observed in the heart. Moreover, morphine withdrawal induces Fos expression, an enhancement of NA turnover and an increase in the total TH levels. When the selective PKA inhibitor HA-1004 was infused, concomitantly with morphine pellets, it diminished the increase in NA turnover and the total TH levels observed in morphine-withdrawn rats. However, this inhibitor neither modifies the morphine withdrawal induced Fos expression nor the increase of nonphosphorylated TH levels. The present findings indicate that an up-regulated PKA-dependent transduction pathway might contribute to the activation of the cardiac catecholaminergic neurons in response to morphine withdrawal and suggest that Fos is not a target of PKA at heart levels.     

CNQX对电刺激隐神经诱发大鼠扣带回前部神经元c-Fos基因表达的影响

目的阐明伤害性电刺激隐神经(saphenous nerve,SN)能否引起扣带回前部(anterior cingulategyrus,ACG)神经元c-Fos基因表达及其发生机制。方法用免疫组化方法研究伤害性电刺激SN后不同时间,ACG神经元c-Fos基因表达的变化,以及尾静脉注射α-氨基3-羟基5-甲基4-异恶唑丙酸/海人藻氨酸(α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid/kainate,AMPA/kainate)受体拮抗剂受体是谷氨酸受体之一,6-氰基-7-硝基喹喔啉-2,3-二酮(6-cyano-7-nitroquinoxaline-2,3-dike-tone,CNQX)对该变化的影响。结果伤害性电刺激SN后30 min ACG神经元Fos蛋白表达明显增加,60 min增加最明显,120 min后开始消退;并且尾静脉注射CNQX拮抗了伤害性电刺激SN引起的ACG神经元Fos蛋白表达的显著增加。结论伤害性电刺激SN能够引起ACG神经元Fos蛋白表达的显著增加,这种表达呈时间依赖性,提示ACG存有SN代表区,能够感受SN传入的伤害性信息;CNQX拮抗了伤害性电刺激SN引起的ACG神经元Fos蛋白表达的显著增加,提示AMPA/kainate受体参与此过程。     

Atypical antipsychotic properties of blonanserin, a novel dopamine D2 and 5-HT2A antagonist

Blonanserin is a novel antipsychotic agent that preferentially interacts with dopamine D₂ and 5-HT_2A receptors. To assess the atypical properties of blonanserin, we evaluated its propensity to induce extrapyramidal side effects (EPS) and to enhance forebrain Fos expression in mice. The actions of AD-6048, a primary metabolite of blonanserin, in modulating haloperidol-induced EPS were also examined. Blonanserin (0.3-10 mg/kg, p.o.) did not significantly alter the pole-descending behavior of mice in the pole test or increase the catalepsy time, while haloperidol (0.3-3 mg/kg, p.o.) caused pronounced bradykinesia and catalepsy. Blonanserin and haloperidol at the above doses significantly enhanced Fos expression in the shell (AcS) region of the nucleus accumbens and dorsolateral striatum (dlST). The extent of blonanserin-induced Fos expression in the AcS was comparable to that induced by haloperidol. However, the striatal Fos expression by blonanserin was less prominent as compared to haloperidol. Furthermore, combined treatment of AD-6048 (0.1-3 mg/kg, s.c.) with haloperidol (0.5 mg/kg, i.p.) significantly attenuated haloperidol-induced bradykinesia and catalepsy. The present results show that blonanserin behaves as an atypical antipsychotic both in inducing EPS and enhancing forebrain Fos expression. In addition, AD-6048 seems to contribute at least partly to the atypical properties of blonanserin.     

A role for the habenula in the regulation of locomotor activity cycles

Although much is known about the regulation of the circadian rest-activity cycle by the hypothalamic suprachiasmatic nucleus in nocturnal rodents, little is known about the neural substrates that regulate the temporal organization of nocturnal activity within the active phase. In this report, data are presented in Syrian hamsters to implicate the habenula - believed to be involved in motivation, reward and motor control--as a candidate site for such a role. First, by examining hamsters during the day and night and by introducing a 'novel' running wheel in order to induce daytime motor activity, we showed that immunoreactive c-Fos expression in the lateral and medial habenula is related to motor activity/arousal. Second, by transecting the habenula's major efferent pathway (fasciculus retroflexus), we showed that the interruption of habenula neural output alters the daily amount of motor activity, lengthens the period of the circadian rest-activity rhythm and disrupts the species-typical pattern of nocturnal motor activity, measured as either wheel-running behavior or general locomotor activity. Instead of the usual pattern of night-time locomotion, characterized by a prolonged bout of elevated activity in the early night followed by shorter sporadic bouts or the cessation of activity altogether, lesioned animals exhibited a more homogeneous, undifferentiated temporal profile extending across the night. These data suggest a previously unrecognized function of the habenula whereby it regulates the temporal pattern of activity occurring within a circadian rest-activity window set by the suprachiasmatic nucleus.     

体外切割损伤脊髓神经元对其Fos、ChAT及GAD表达的影响

目的:研究切割损伤对体外培养脊髓神经元Fos、胆碱乙酰转移酶(ChAT)及谷氨酸脱羧酶(GAD)表达的影响。方法:脊髓神经元纯化培养后分别计数碘化丙啶(PI)阳性细胞数和微管相关蛋白2(MAP2)阳性细胞数,决定脊髓神经元纯度。根据本实验室已建立的损伤模型,对原代纯化培养脊髓神经元进行切割损伤。通过免疫组化及WesternBlot方法比较神经元损伤前后Fos、ChAT和GAD表达的变化情况。结果:脊髓神经元纯化培养后纯度达到92%。免疫组化及WesternBlot显示,切割损伤组与正常组相比,Fos、GAD表达上调,而ChAT表达降低。结论:Fos、GAD和ChAT可能参与脊髓神经元急性损伤及随后的修复过程,其生物学意义有待进一步探讨。     

Activation in neural networks controlling ingestive behaviors: what does it mean, and how do we map and measure it?

Over the past thirty years many of different methods have been developed that use markers to track or image the activity of the neurons within the central networks that control ingestive behaviors. The ultimate goal of these experiments is to identify the location of neurons that participate in the response to an identified stimulus, and more widely to define the structure and function of the networks that control specific aspects of ingestive behavior. Some of these markers depend upon the rapid accumulation of proteins, while others reflect altered energy metabolism as neurons change their firing rates. These methods are widely used in behavioral neuroscience, but the way results are interpreted within the context of defining neural networks is constrained by how we answer the following questions. How well can the structure of the behavior be documented? What do we know about the processes that lead to the accumulation of the marker? What is the function of the marker within the neuron? How closely in time does the marker accumulation track the stimulus? How long does the marker persist after the stimulus is removed? We will review how these questions can be addressed with regard to ingestive and related behaviors. We will also discuss the importance of plotting the location of labeled cells using standardized atlases to facilitate the presentation and comparison of data between experiments and laboratories. Finally, we emphasize the importance of comprehensive and accurate mapping for using newly emerging technologies in neuroinfomatics.     

Knockdown of c-Fos suppresses the growth of human colon carcinoma cells in athymic mice

Here we have investigated whether inhibition of c-Fos expression in RKO human colon carcinoma cells (HCCCs) would result in reduced TGFβ1 expression and suppression of tumor growth in athymic mice. We stably transfected RKO cells with c-Fos small interfering RNA (siRNA) or with the corresponding control siRNA. Using these stable cell lines, we demonstrated that siRNA-c-Fos significantly suppressed both AP-1 binding, promoter reporter activity at the proximal AP-1 site in the TGFβ1 promoter, and TGFβ1 production. Further, we established colon cancer xenografts with each of RKO-siRNA-EV, RKO-siRNA-Ctrl and RKO-siRNA-c-Fos cells. By 24 days, the tumor size of RKO-siRNA-c-Fos xenografts was 40% that of either RKO-EV or RKO-siRNA-Ctrl. Immunohistochemistry (IHC) of tumor xenografts demonstrated that siRNA-c-Fos significantly blocked c-Fos expression, and consequently expression of TGFβ1. However, expression of TGFβ2 and TGFβ3 were unaffected. Overall, our results demonstrate that blockade of TGFβ1 production by siRNA-c-Fos effectively suppressed tumor growth in vivo.