以α7 nAChR为靶点的药物研究进展

α7 nAChR属于烟碱型乙酰胆碱受体,是由5个α7单体组成的配体门控离子通道。α7 nAChR的配体结合位点主要有两种,即激动剂(拮抗剂)结合位点以及变构调节位点。α7 nAChR是精神分裂症认知障碍以及阿尔茨海默病药物研究的一个重要靶点,现已有多个治疗药物处在临床试验阶段。本文主要综述了α7 nAChR激动剂以及变构调节剂药物的研究进展。     

肌肉型乙酰胆碱受体在HEK293细胞上的表达

目的　利用受体克隆技术 ,建立骨骼肌细胞乙酰胆碱受体 (m nAChR)的实验模型 ,以便进行各种药理研究。方法　应用分子生物学技术将编码小鼠m nAChR的α、β、γ、δ、ε亚基之cDNA分别重组于真核细胞表达质粒pcDNA3 1+ 上 ,用脂质体转染技术 ,将重组后的pcDNA3 1+ 导入HEK2 93细胞 ,使其细胞膜上表达胚胎型乙酰胆碱受体 (γ nAChR)和成年型乙酰胆碱受体 (ε nAChR) ,这样建立了两种m nAChR亚型的实验模型。应用全细胞膜片钳技术测量转染细胞对该受体的内生配基乙酰胆碱的反应。结果　乙酰胆碱可激发转染细胞产生一内向电流 ,电流的大小与乙酰胆碱呈浓度依赖性。结论　HEK2 93细胞在转染后 2 4～ 72h内 ,其细胞膜上表达γ nAChR或ε nAChR ,用于进行各种药理实验。     

胆碱能抗炎通路α7烟碱型乙酰胆碱受体的最新研究进展

α7nAChR（α7 nicotinic acetylcholine receptor）属于烟碱型乙酰胆碱受体（nAChRs）,是机体胆碱能抗炎通路的关键受体,在免疫系统的神经调控中发挥重要作用。近期研究发现,α7nAChR还参与调节免疫以外的多种生理病理过程,如非酒精性脂肪肝、血管新生、保护心脏等。此外,α7nAChR在神经退行性疾病等与能量代谢紧密关联。本文综述α7nAChR在治疗炎症、改善能量代谢中发挥的作用,以及α7nAChR参与治疗的新方向。     

烟碱致动脉粥样硬化的N胆碱受体信号通路

动脉粥样硬化是一种血管炎症性疾病.烟碱（尼古丁）是香烟的主要成分之一,是许多心血管疾病（如动脉粥样硬化）的致病危险因素.最近的研究表明,烟碱可与细胞表面的烟碱型乙酰胆碱受体（nAChR）高度结合并加速动脉粥样硬化的发展,nAChR在血管的各类细胞中都有不同量的表达.因此,本综述总结nAChR及配体在烟碱致动脉粥样硬化的发病机制中的作用,以及基于nAChR的信号通路在相关细胞（如血管平滑肌细胞、内皮细胞、血小板及免疫细胞）中对动脉粥样硬化的作用,同时讨论这些通路是如何影响斑块的稳定和发展的.最后将讨论nAChR作为治疗动脉粥样硬化分子靶点的可能性.     

烟碱α4β2型受体与相关疾病及药物研究进展

α4β2型烟碱受体(nAChR)是一种配体门控离子通道,在整个神经系统几乎都有分布,参与乙酰胆碱、多巴胺、γ-氨基丁酸、去甲肾上腺素等神经递质的调节和释放,在机体的学习、记忆、认知、注意力、炎症以及疼痛中发挥重要作用。大量研究表明,α4β2型nAChR是阿尔茨海默症、帕金森病、癫痫、抑郁症、尼古丁依赖、疼痛等神经系统性疾病的重要治疗靶点,对以老年痴呆为主的神经退行性疾病早期诊断和疗效检测具有重要意义。本文总结了α4β2型nAChR在神经系统性疾病治疗中的作用、机制以及相关药物研究进展,为筛选和开发更合适的α4β2型nAChR相关化合物提供理论依据。     

α-芋螺毒素特异性结合受体-神经型烟碱乙酰胆碱受体的同源模建及功能预测

目的探讨神经型烟碱乙酰胆碱受体能被其竞争性拮抗剂α-芋螺毒素选择性阻断的机理。方法采用同源模建的方法构建神经型烟碱乙酰胆碱受体α-7亚型的三维空间结构,并利用分子对接的方法与已知空间构像的α-芋螺毒素对接。结果已构建的神经型烟碱乙酰胆碱受体α-7亚型结构合理,并与已知空间构像的α-芋螺毒素对接成功。结论传统的烟碱型乙酰胆碱受体拮抗剂缺乏专一性,而靶向神经元神经型烟碱乙酰胆碱受体的α-芋螺毒素种类多,特异性强,与不同亚单位组成的受体亲和力不同,应用潜力很大。     

加兰他敏作用机制与临床应用

加兰他敏是一种菲啶类生物碱,具有抑制胆碱酯酶活性和调节烟碱乙酰胆碱受体(nAChR)活性的双重作用,多用于阿尔茨海默病(AD)、精神分裂症的治疗.新近研究发现,该药还可抑制钾离子通道,激活多巴胺受体,并可通过抑制后超极化、干预代谢等保护中枢神经元.     

三环哌酯对培养交感神经元烟碱受体的阻断作用

目的:观察烟碱受体拮抗剂三环哌酯对烟碱诱发电流的作用.方法:用高阻抗封接膜片箝全细胞记录技术在培养的新生大鼠颈上神经节观察三环哌酯对烟碱诱发电流的作用.结果:三环哌酯竞争性地抑制烟碱诱发电流,其抑制作用没有电压依赖性,但能加速烟碱受体失敏.结论:三环哌酯抑制神经元烟碱受体的作用部位在变构位点而不是在离子通道或乙酰胆碱识别位点.     

小儿重症肌无力的治疗现状及进展

重症肌无力(myasthenia gravis,MG)是累及神经-肌肉接头处突触后膜上的烟碱型乙酰胆碱受体( nicotinic acetylcholine receptor,nAChR),由乙酰胆碱受体抗体介导、细胞免疫依赖、补体参与的自身免疫性疾病.对于MG的治疗包括:对症治疗、免疫抑制剂、血浆置换、免疫球蛋白、胸腺切除等.随着MG发病机制的深入研究及新疗法的开展,使该病的临床疗效明显提高,病死率明显下降.本文就小儿MG的治疗现状及进展作一综述.     

儿茶酚抑素与高血压

儿茶酚抑素作用于内源性烟碱型乙酰胆碱受体(nAChR)可抑制儿茶酚胺释放,具有扩血管、降血压、降低心肌收缩力和促进血管生成作用.本文综述儿茶酚抑素对血压的调节作用及其异构体在高血压治疗中的研究进展.     

Structural determinates for apolipoprotein E-derived peptide interaction with the alpha7 nicotinic acetylcholine receptor

Neuronal nicotinic acetylcholine receptor (nAChR) signaling has been implicated in a variety of normal central nervous system (CNS) functions as well as an array of neuropathologies. Previous studies have demonstrated both neurotoxic and neuroprotective actions of peptides derived from apolipoprotein E (apoE). It has been discovered that apoE-derived peptides inhibit native and recombinant alpha7-containing nAChRs, indicating a direct interaction between apoE peptides and nAChRs. To probe the structure/function interaction between alpha7 nAChRs and the apoE peptide apoE(141-148), experiments were conducted in Xenopus laevis oocytes expressing wild-type and mutated nAChRs. Mutation of Trp55 to alanine blocks apoE peptide-induced inhibition of acetylcholine (ACh)-mediated alpha7 nAChR responses. Additional mutations at Trp55 suggest that hydrophobic interactions between the receptor and apoE(141-148) are essential for inhibition of alpha7 nAChR function. A mutated apoE peptide also demonstrated decreased inhibition at alpha7-W55A nAChRs as well as activity-dependent inhibition of both wild-type alpha7 nAChRs and alpha7-W55A receptors. Finally, a three-dimensional model of the alpha7 nAChR was developed based on the recently refined Torpedo marmorata nACh receptor. A structural model is proposed for the binding of apoE(141-148) to the alpha7 nAChR where the peptide binds at the interface between two subunits, near the ACh binding site. Similar to the functional data, the computational docking suggests the importance of hydrophobic interactions between the alpha7 nAChR and the apoE peptide for inhibition of receptor function. The current data suggest a mode for apoE peptide binding that directly blocks alpha7 nAChR activity and consequently may disrupt nAChR signaling.     

Discovery and structure-activity relationship of quinuclidine benzamides as agonists of alpha7 nicotinic acetylcholine receptors

A library of benzamides was tested for alpha7 nicotinic acetylcholine receptor (nAChR) agonist activity using a chimeric receptor in a functional, cell-based, high-throughput assay. From this library, quinuclidine benzamides were found to have alpha7 nAChR agonist activity. The SAR diverged from the activity of this compound class verses the 5-HT(3) receptor, a structural homologue of the alpha7 nAChR. PNU-282987, the most potent compound from this series, was also shown to open native alpha7 nAChRs in cultured rat neurons and to reverse an amphetamine-induced gating deficit in rats.     

Functional changes of nicotinic acetylcholine receptor in muscle and lymphocyte of myasthenic rats following acute dimethoate poisoning

The mechanism underlying intermediate myasthenia syndrome (IMS) following acute organophosphate poisoning remains largely unknown. Previous studies indicated that the mechanism of myasthenia in rats and IMS patients is most likely due to a postsynaptic neurotransmission blocking at neuromuscular junctions (NMJ). Nicotinic acetylcholine receptor (nAChR) is a key postsynaptic component at NMJ. Whether functional changes of nAChR are related to the development of myasthenia has not been demonstrated and addressed in vivo so far. In this study, we attempted to investigate temporal and spatial changes of nAChR in the blood lymphocyte, muscle and brain of rats during the course of myasthenia after acute dimethoate poisoning by using radioligand-binding assay. We found that specific nAChR binding activity in the gastrocnemius muscle and blood lymphocytes of myasthenia rats was significantly increased at 48h after dimethoate poisoning. However, no changes of nAChR binding activity were found in the lymphocytes and muscle of non-myasthenia rats which were sacrificed at 1h after intoxication. Interestingly, no changes of nAChR and muscarinic acetylcholine receptor (mAChR) binding activity were found in the cerebrum and cerebellum of all rats after dimethoate intoxication either at 1 or 48h. The change of nAChR specific binding activity in the lymphocytes is parallel with that in the skeletal muscle during the development of myasthenia. This implied that the changes of nAChR receptor binding activity in the skeletal muscle and lymphocytes are highly associated with the development of myasthenia. The functional changes of nAChR at NMJ might play an important role in the paralysis of skeletal muscle following acute organophosphates (OPs) poisoning.     

α7 nicotinic acetylcholine receptors: a therapeutic target in the structure era

The nicotinic acetylcholine receptors (nAChR) are ligand-gated ion channels involved in cognitive processes and are associated with brain disorders which makes them interesting drug targets. This article presents a general overview of the receptor to introduce the α7 nAChR as a drug target. The advances in understanding of the structure/function properties of the nAChR produced during the last decade are detailed as they are crucial for rational drug design. The allosteric properties of the nAChR will also be described because they also have important consequences for drug design.     

Selective nicotinic receptor antagonists: effects on attention and nicotine-induced attentional enhancement

Rationale  

The question of the subtype(s) of the nicotinic acetylcholine receptor (nAChR) mediating the attention-enhancing effects of nicotine is still unsettled. While early studies pointed towards subtypes other than the homomeric α7 nAChR, pro-cognitive effects of α7 nAChR agonists have since been demonstrated.     

Activation of the alpha-7 nicotinic acetylcholine receptor (α7 nAchR) reverses referred mechanical hyperalgesia induced by colonic inflammation in mice

In the current study, we investigated the effect of the activation of the alpha-7 nicotinic acetylcholine receptor (α7 nAchR) on dextran sulphate sodium (DSS)-induced colitis and referred mechanical hyperalgesia in mice. Colitis was induced in CD1 male mice through the intake of 4% DSS in tap water for 7 days. Control mice received unadulterated water. Referred mechanical hyperalgesia was evaluated for 7 days after the beginning of 4% DSS intake. Referred mechanical hyperalgesia started within 1 day after beginning DSS drinking, peaked at 3 days and persisted for 7 days. This time course profile perfectly matched with the appearance of signs of colitis. Both acute and chronic oral treatments with nicotine (0.1-1.0 mg/kg, p.o.) were effective in inhibiting the established referred mechanical hyperalgesia. The antinociceptive effect of nicotine was completely abrogated by cotreatment with the selective α7 nAchR antagonist methyllycaconitine (MLA) (1.0 mg/kg). Consistent with these results, i.p. treatment with the selective α7 nAchR agonist PNU 282987 (0.1-1.0 mg/kg) reduced referred mechanical hyperalgesia at all periods of evaluation. Despite their antinociceptive effects, nicotinic agonists did not affect DSS-induced colonic damage or inflammation. Taken together, the data generated in the present study show the potential relevance of using α7 nAchR agonists to treat referred pain and discomfort associated with inflammatory bowel diseases.     

Novel α3β4 nicotinic acetylcholine receptor-selective ligands. Discovery, structure-activity studies, and pharmacological evaluation

Antagonist activity at the α3β4 nicotinic acetylcholine receptor (nAChR) is thought to contribute to the antiaddictive properties of several compounds. However, truly selective ligands for the α3β4 nAChR have not been available. We report the discovery and SAR of a novel class of compounds that bind to the α3β4 nAChR and have no measurable affinity for the α4β2 or α7 subtype. In functional assays the lead compound antagonized epibatidine-induced Ca(2+) flux in α3β4-transfected cells in a noncompetitive manner.