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Dendrites and spines undergo dynamic changes in physiological and pathological conditions. Dendritic outgrowth has been observed in surviving neurons months after ischemia, which is associated with the functional compensation. It remains unclear how dendrites in surviving neurons are altered shortly after ischemia, which might reveal the mechanisms underlying neuronal survival. Using primary cortical cultures, we monitored the dendritic changes in individual neurons after oxygen-glucose deprivation (OGD). Two to four hours of OGD induced approximately 30–50% cell death in 24 h. However, the total dendritic length in surviving neurons was significantly increased after OGD with a peak at 6 h after re-oxygenation. The increase of dendritic length after OGD was mainly due to the sprouting rather than the extension of the dendrites. The dendritic outgrowth after 2 h of OGD was greater than that after 4 h of OGD. Application of NMDA receptor blocker MK-801 abolished OGD-induced dendritic outgrowth, whereas application of AMPA receptor antagonist CNQX had no significant effects. These results demonstrate a NMDA receptor-dependent dendritic plasticity shortly after OGD, which provides insights into the early response of surviving neurons after ischemia. 相似文献
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目的 探讨伤害性刺激隐神经(SN)能否诱发脊髓神经元Fos蛋白表达及发生机制.方法 应用免疫组化方法观察伤害性刺激SN和尾静脉注射谷氨酸非NMDA受体拮抗剂(CNQX)后诱发脊髓神经元Fos蛋白表达的变化.结果 伤害性刺激SN后,诱导脊髓神经元Fos蛋白表达显著增强,CNQX拮抗了Fos蛋白表达的显著增强.结论 以伤害性刺激SN模拟躯体痛后,CNQX拮抗了伤害性刺激SN引起的脊髓神经元Fos蛋白表达的显著增加,表明非NMDA受体在躯体痛的调控中起到了重要的作用. 相似文献
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目的:观察逍遥散和6-氰基-7-硝喹啉-2,3-双酮(CNQX)对慢性束缚应激所致肝郁脾虚证大鼠中枢AMPA受体及其相关蛋白表达的影响,探讨逍遥散的作用机制。方法:将100只雄性SD大鼠随机分为正常组(A组)、假手术组(B组)、模型组(C组)、逍遥散组(D组)、CNQX组(E组)和逍遥散+CNQX组(F组)。C、D、E、F组大鼠通过连续21d慢性束缚应激建立肝郁脾虚证候模型,D、F组大鼠每天束缚前灌服逍遥散5.32g/kg,E、F组大鼠隔天右侧杏仁核区微量注射α-氨基羟甲基恶唑丙酸(AMPA)受体拮抗剂CNQX 0.5μL。各组动物第22d处死,免疫组化方法检测海马CA1区、CA3区、基底外侧杏仁核(BLA)谷氨酸受体2/3(GluR2/3)、N-乙基顺丁烯二酰亚胺敏感性的融合蛋白(NSF)、PKC作用蛋白1(PICK1)水平。结果:模型大鼠GluR2/3在海马CA1、CA3区明显减少,BLA区明显增加;NSF在海马CA1、CA3区有减少趋势;PICK1在海马CA3区明显增加。CNQX和逍遥散对模型大鼠GluR2/3 PICK1在海马的变化均有调节作用。逍遥散联合CNQX作用于慢性束缚应激大鼠与单独使用逍遥散或CNQX后呈现一致性。结论:调节AMPA受体及其相关蛋白在海马各区和杏仁核的兴奋性至少是逍遥散调节突触可塑性、进一步治疗应激和抑郁的作用途径之一。 相似文献
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Phencyclidine (PCP) is a psychotomimetic drug that elicits schizophrenia-like symptoms in healthy individuals, and animals administered PCP are now considered a reliable pharmacological model of schizophrenia. Recent studies have shown that systemically administered PCP produces long-lasting activation of medial prefrontal cortex (mPFC) neurons, and that hyperactivation of mPFC neurons plays a critically important role in the development of PCP-induced behavioral abnormalities. However, the receptors mediating this mPFC activation have not been clearly determined. Here, we examined the effects of local application of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), an AMPA/kainate glutamate receptor antagonist, scopolamine, a muscarinic acetylcholine receptor antagonist, and mecamylamine, a nicotinic acetylcholine receptor antagonist, on the increase in firing rate of mPFC neurons induced by systemic PCP in anesthetized rats. After tonic activation of mPFC neurons by PCP had been established, CNQX, scopolamine, or mecamylamine was iontophoretically applied or pressure-ejected on the recorded neuron. CNQX suppressed PCP-induced elevation of firing rate to baseline level, though scopolamine and mecamylamine each induced little change in firing rate. These findings suggest that PCP-induced activation of mPFC neurons is mediated primarily via AMPA/kainate glutamate receptors. 相似文献
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Hatam M Nasimi A 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2007,178(3):394-401
The bed nucleus of the stria terminalis (BST) is a part of the limbic system. Two studies have shown that microinjection of
l-glutamate in the BST elicited cardiovascular depressive and bradycardic responses, but in one study, both pressor and depressor
responses were observed in the chemical stimulation of BST by glutamate in the urethane-anesthetized rats. Also, the roles
of glutamate receptor subtypes have not been investigated yet. The aim of this study was to find the effects of glutamate
and its receptors on the blood pressure and heart rate in the BST of urethane-anesthetized rats. The drugs (50 nl) were microinjected
into the BST of anaesthetized rats. The blood pressure and heart rate were recorded throughout each experiment. The average
changes in the mean arterial pressure and heart rate at different intervals were compared both within each case group and
between the case and the control groups, using repeated measures ANOVA. Microinjection of l-glutamate (0.25 M) into the BST resulted in the decrease of the mean arterial pressure (−18.85 ± 3.84 mmHg) and heart rate
(−18 ± 4 beats/min). Injection of AP5, antagonist of glutamate NMDA receptor (2.5 , 5 mM) and CNQX, antagonist of glutamate
AMPA receptor (0.5, 1 mM) had no significant effect on the mean arterial pressure and heart rate. Either Ap5 or CNQX, when
co-injected with glutamate, abolished the depressor and bradycardic effects of glutamate, suggesting that simultaneous activation
of both glutamate receptors is necessary for the effect of glutamate system to emerge. 相似文献
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目的 研究乙醇、乙醛对原代培养大鼠大脑皮质神经元神经甾体水平的影响以及与AMPA受体调控的相关性. 方法 应用AMPA受体拮抗剂CNQX阻断AMPA受体,用50mmol/L乙醇或25 mmol/L乙醛处理神经元,收集细胞培养上清,采用高效液相色谱质谱法分离测定游离型神经甾体孕烯醇酮(PREG)、脱氢表雄酮(DHEA)、别孕烯醇酮(AP)及结合型神经甾体脱氢表雄酮硫酸酯(DHEAS)、孕烯醇酮硫酸酯(PREGS)的含量,观察CNQX对乙醇、乙醛调控原代培养神经元神经甾体水平的影响. 结果乙醇可明显升高神经元PREG、AP和PREGS的水平,与PBS对照组比较差异有统计学意义(P<0.05);乙醛可明显升高神经元PREG、DHEA、PREGS和DHEAS的水平,与PBS对照组比较差异有统计学意义(P<0.05).CNQX反转了乙醇升高PREG、PREGS水平的作用以及乙醛升高PREG、DHEAS水平的作用,却使AP水平明显升高,组间比较差异有统计学意义(P<0.05). 结论 乙醇、乙醛对大脑皮质神经元神经甾体PREG、DHEA、AP、PREGS和DHEAS的影响各不相同,CNQX反转了乙醇上调PREG、PREGS水平的作用以及乙醛上调PREG、DHEAS水平的作用. 相似文献
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Radenovic L Selakovic V Kartelija G Todorovic N Nedeljkovic M 《Brain research bulletin》2004,64(1):85-93
The involvement of NMDA and AMPA/kainate receptors in the induction of superoxide radical production in the rat brain was examined after injection of kainate, non-NMDA receptor agonist, kainate plus 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), selective AMPA/kainate receptor antagonist, or kainate plus 2-amino-5-phosphonopentanoic acid (APV), selective NMDA receptor antagonist. Competitive glutamate receptor antagonists were injected with kainate unilaterally into the CA3 region of the rat hippocampus. We investigated superoxide production and mitochondrial MnSOD activity after injection. The measurements took place at different times (5, 15 min, 2, 48 h and 7 days) in the ipsi- and contralateral hippocampus, forebrain cortex, striatum, and cerebellum homogenates. Used glutamate antagonists APV and CNQX both expressed sufficient neuroprotection in sense of decreasing superoxide production and increasing MnSOD levels, but with differential effect in mechanisms and time dynamics. Our findings suggest that NMDA and AMPA/kainate receptors are differentially involved in superoxide production. Following intrahippocampal antagonists injection they, also, interpose different neuroprotection effect on the induction of MnSOD activity in distinct brain regions affected by the injury, which are functionally connected via afferents and efferents. It suggests that MnSOD protects the cells in these regions from superoxide-induced damage and therefore may limit the retrograde and anterograde spread of neurotoxicity. 相似文献
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AMPA receptors (AMPARs) mediate the majority of fast synaptic transmission in the CNS of vertebrates. They are believed to be associated with members of the transmembrane AMPA receptor regulatory protein (TARP) family. TARPs mediate the delivery of AMPA receptors to the plasma membrane and mediate their synaptic trafficking. Moreover, TARPs modulate essential electrophysiological properties of AMPA receptors. Here, we compare the influence of rat TARPs (gamma2, gamma3, gamma4, and gamma8) on pharmacological properties of rat GluR1(Q)flip. We show that agonist potencies are increased by all TARPs, but to individually different extents. On the other hand, all TARPs increase agonist potencies at the virtually non-desensitizing mutant GluR1-L479Y almost identically. Comparison of the influence of individual TARPs on relative agonist efficacies confirmed that the TARPs can be functionally subdivided into two subgroups, one consisting of gamma2 and gamma3 and one consisting of gamma4 and gamma8. Surprisingly, we found that TARPs convert certain AMPA receptor antagonists to agonists. The potency of one of these converted antagonists is dependent on the particular TARP. Moreover, TARPs (except gamma4) reduce the ion channel block by the synthetic Joro spider toxin analog 1-naphthylacetyl spermine (NASP). In addition, TARPs increase the permeability of the receptor to calcium, indicating that TARPs directly modulate important ion pore properties. In summary, the data presented herein will illustrate and help to understand the previously unexpected complexities of modulation of AMPA receptor pharmacological properties by TARPs. 相似文献
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The quinoxaline derivative, 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo (F) quinoxaline (NBQX), significantly reduced the currents evoked by exogenous application of quisqualate (QQ), kainate (KA) and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) when applied to ganglion cells, using whole-cell recording in a slice preparation of the tiger salamander retina. A comparison between NBQX and CNQX indicates that NBQX is more effective in blocking AMPA receptors. Also, at up to 10 μM, NBQX has no effect on NMDA-induced currents. Thus at this concentration, NBQX shows no affinity for the glycine binding site of NMDA receptors. For this reason, NBQX is preferred over CNQX for a more effective and selective antagonism toward non-NMDA receptors. 相似文献