AMPA receptor involvement in 5-hydroxytryptamine2A receptor-mediated pre-frontal cortical excitatory synaptic currents and DOI-induced head shakes

Glutamate plays an important role in the psychotomimetic effects of both channel blocking N-methyl D-aspartate (NMDA) receptor antagonists and hallucinogenic drugs which activate 5-hydroxytryptamine2A (5-HT2A) receptors. Previous work suggested that activation of non-NMDA ionotropic glutamate receptors mediates the effects of 5-HT-induced excitatory post-synaptic potentials/currents (EPSPs/EPSCs) when recording from layer V pyramidal cells in the rat medial pre-frontal cortex (mPFC). However, those effects are mediated by either alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) or kainate receptors of the iGluk5 subtype. To test whether activation of AMPA receptors is sufficient to mediate 5-HT-induced EPSCs, a 2,3-benzodiazepine that selectively blocks AMPA receptors was assessed. This selective AMPA receptor antagonist potently suppressed 5-HT-induced EPSCs. Since phenethylamine hallucinogens induce head shakes by activating 5-HT2A receptors in the mPFC and this action is modulated by glutamate, we also examined whether selective blockade of AMPA receptors would suppress DOI-induced head shakes. As predicted, we found that selective blockade of AMPA receptors suppressed DOI-induced head shakes. Given evidence that activation of AMPA receptors is an important downstream effect for both channel blocking NMDA receptor antagonists and phenethylamine hallucinogens, we also tested multiple doses of DOI with a sub-anesthetic dose of MK-801. Synergistic action between these two classes of psychotomimetic drugs was demonstrated by MK-801 enhancing DOI-induced head shakes and locomotor activity. These findings expand the dependence of both channel blocking NMDA receptor antagonists and phenethylamine hallucinogens on enhancing extracellular glutamate.     

Separation stress, litter size, and the rewarding effects of low-dose morphine in the dams of maternally separated rats

Potential differences in sensitivity to the rewarding effects of morphine as a function of litter separation stress were assessed in post-weaning rat dams. During the first two weeks postnatal, Sprague-Dawley rat litters were subjected to daily 15- or 180-min sessions of dam-pup separation while control litters only experienced twice-weekly animal facility care. One week after weaning, the dams (n=7 per group) underwent a fully unbiased conditioned place preference (CPP) procedure to 1 mg/kg subcutaneous morphine. CPP responses after each conditioning cycle were recorded. Rates of acquisition and asymptotic levels of CPP were comparable in all groups; however, an inverse relationship between litter size and magnitude of morphine CPP was revealed. Although these initial data indicate no differential sensitivity to the rewarding effects of low-dose morphine produced by the stress of litter separation, this assessment of litter size and drug-induced place conditioning in post-weaning litter-separated dams is the first of its kind. Potential effects of other doses, drugs of abuse and post-partum manipulations remain to be evaluated within this emerging etiological model.     

Effect of memantine and CNQX in the acquisition, expression and reinstatement of cocaine-induced conditioned place preference

The present study evaluates the effect of memantine, a non-competitive N-methyl-d-aspartate (NMDA) glutamate receptor antagonist and CNQX, an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist on the rewarding effects of cocaine in mice, using the conditioned place preference (CPP) paradigm. Cocaine-induced CPP was studied pairing this drug with different memantine or CNQX doses during either the acquisition or the expression phase of the procedure. Once CPP was established, and the preference extinguished, reinstatement was induced by a priming dose of cocaine. Both antagonists, which in themselves do not present motivational actions on the preference shown by the animals, abolished the acquisition and expression of the cocaine-induced CPP. Neither of the antagonists precipitated reinstatement of the preference induced by cocaine but memantine blocked the cocaine-primed reinstatement. Our results suggest that cocaine-induced CPP and reinstatement is largely dependent on glutamate neurotransmission, and confer a putative role for memantine among the tools useful for cocaine management and treatment.     

部分国家药品证明性文件（CPP）概述

为了更好的加强对进口药品的监管,保证其安全性、有效性,对美国、英国等国家药品管理机构出具的CPP文件进行初步介绍,并探讨进口药品形式审查过程中应注意的问题.     

Analysis of in vitro toxicity of five cell-penetrating peptides by metabolic profiling

Cell-penetrating peptides (CPPs) are promising candidates for safe and efficient delivery vectors for a wide range of cargoes. However, any compound that is internalized into cells may affect the cell homeostasis. The plethora of possible biological responses makes large scale “omics” studies appealing approaches for hunting any unsuspected side-effects and evaluate the toxicity of drug candidates. Here we have compared the alterations in cytosolic metabolome of CHO cells caused by five representatives of the most common CPPs: transportan (TP), penetratin (pAntp), HIV Tat derived peptide (pTat), nonaarginine (R₉) and model amphipathic peptide (MAP). Analysis was done by liquid chromatography–mass spectrometry techniques, principal component analysis and heatmap displays. Results showed that the intracellular metabolome was the most affected by TP followed by pTat and MAP. Only minor changes could be associated with pAntp or R₉ treatment. The cells could recover from a treatment with 5 μM TP, but no recovery was observed at higher concentration. Both metabolomic and control experiments showed that TP affected cellular redox potential, depleted energy and the pools of purines and pyrimidines. In conclusion, we have performed a metabolomic analysis comparing the safety of cell-penetrating peptides and demonstrate the toxicity of one of them.     

Ca(2+)-independent caspase-3 but not Ca(2+)-dependent caspase-2 activation induced by oxidative stress leads to SH-SY5Y human neuroblastoma cell apoptosis

Continuous and long-lasting exposure to tert-butylhydroperoxide (t-BOOH) increased the number of apoptotic SH-SY5Y human neuroblastoma cells both in the presence and in the absence of the intracellular Ca(2+) ion chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). In addition, t-BOOH exposure induced activation of CPP32, as demonstrated by poly-(ADP-ribose) polymerase (PARP) cleavage, and of ICH-1L caspases. Exposure to t-BOOH also induced a time-dependent release of cytochrome c. Interestingly, in the presence of BAPTA, CPP32 activation still occurred, whereas ICH-1L activation was blocked. Ac-DEVD-CHO, an inhibitor of CPP32 activity, prevented the appearance of apoptotic cells, whereas the inhibitor of ICH-1L activity Z-VDVAD-FMK did not. Collectively, these findings demonstrate that in SH-SY5Y neuroblastoma cells exposure to continuous and long-lasting oxidative stress induced activation of caspase-3 that was independent of intracellular Ca(2+) ion concentration ([Ca(2+)](i)) elevation but led to cell apoptosis. In contrast, caspase-2 activation was dependent on [Ca(2+)](i) increase but did not result in apoptosis.     

经Ugi四组分缩合反应合成CPP32抑制剂模板

目的找到合适途径来制备所设计的CPP32抑制剂.方法 Ugi四组分缩合反应用于合成拟肽类CPP32抑制剂.结果 合成了关键异腈组分(天冬氨酸衍生异腈3)和CPP32抑制剂模板分子4.结论以基于天冬氨酸衍生异腈3的Ugi四组分缩合反应,合成了CPP32抑制剂4.此新建的方法可用于构建CPP32拟肽类抑制剂化学库.     

颅脑外伤后血浆S-100B蛋白的变化及其与临床、CT、颅内压、脑灌注压的相关研究

目的 ①探讨颅脑外伤后血浆S-100B蛋白变化规律;②探讨血浆S-100B蛋白水平与伤情、CT、ICP、CCP的关系.方法 免疫组化法测定90例各型颅脑损伤患者24h内、3d、7d血浆S-100B蛋白水平,并结合颅脑损伤程度、CT、ICP、CPP进行分析.结果 ①颅脑损伤患者伤后血浆S-100B蛋白浓度立即升高,其程度与脑损伤程度呈正相关;②血浆S-100B蛋白水平与ICP正相关,与CPP负相关;③血浆S-100B蛋白水平随CT图像改变而变化.结论 ①通过对血浆S-100B蛋白浓度变化的动态观察,为颅脑损伤程度的判断提供较为实用的指标.②监测血浆S-100B蛋白浓度,联合CT、ICP、CPP等指标,可更准确地判断病情,为临床治疗提供依据.     

Effects of competitive and noncompetitive NMDA receptor antagonists on kindling and LTP

In the present study, comparative studies of the effects of competitive and noncompetitive antagonists of NMDA receptors (CPP, CGS19755 and MK-801) on two models of neuronal plasticity, kindling and long-term potentiation (LTP), were performed in rats. Systemic administration of CPP (5, 10 mg/kg), CGS19755 (5, 10 mg/kg) or MK-801 (1, 2 mg/kg) strongly retarded kindling development from the amygdala (AM), in which the early stage of kindled seizures and the growth of afterdischarges (ADs) recorded from the AM were significantly suppressed. After establishment of kindling, however, these compounds only reduced the previously AM-kindled seizure stage without shortening the AD duration. These NMDA receptor antagonists with the same dose sufficient for suppressing AM kindling almost completely blocked LTP of the synaptic component in the hippocampal dentate gyrus following high-frequency trains of the perforant path in urethane-anesthetized rats. These results further support the hypothesis that neuronal plasticity is induced by activation of the NMDA receptor complex and one of the basic neuronal mechanisms underlying kindling may be a long-lasting increase in synaptic transmission.     

Pharmacological studies of a rat spatial delayed nonmatch-to-sample task as an animal model of dementia

A variation of the delayed nonmatch-to-sample task in rats has recently been described in which the spatial positions of retractable levers are used as the sample and response cues. The pharmacology of this task has been investigated, with the aim of developing models relevant to the search for compounds active in dementia, particularly Alzheimer's disease. Scopolamine and atropine decreased the accuracy of responding. This was attenuated by physostigmine and THA. Mecamylamine, 8-OH DPAT, CPP, MK-801, and pentobarbital all produced marked accuracy deficits. Diazepam and sodium valproate affected accuracy rather less. Subthreshold doses of mecamylamine and scopolamine given together produced a significant accuracy deficit. All the drugs tested decreased the total trials performed. Prior satiation experiments demonstrated that this rate decrease in itself did not necessarily cause the decrease in accuracy. CPP and MK-801 appeared to produce the largest decrease in accuracy, with the least effect on rate. This selectivity, combined with the emerging role of the NMDA receptor complex in learning, memory, and dementia, encourages the development of this model or similar models in the search for compounds with the potential to treat dementia.