Ischemic postconditioning protects against ischemic brain injury by up-regulation of acid-sensing ion channel 2a

Ischemic postconditioning renders brain tissue tolerant to brain ischemia,thereby alleviating ischemic brain injury.However,the exact mechanism of action is still unclear.In this study,a rat model of global brain ischemia was subjected to ischemic postconditioning treatment using the vessel occlusion method.After 2 hours of ischemia,the bilateral common carotid arteries were blocked immediately for 10 seconds and then perfused for 10 seconds.This procedure was repeated six times.Ischemic postconditioning was found to mitigate hippocampal CA1 neuronal damage in rats with brain ischemia,and up-regulate acid-sensing ion channel 2a expression at the m RNA and protein level.These findings suggest that ischemic postconditioning up-regulates acid-sensing ion channel 2a expression in the rat hippocampus after global brain ischemia,which promotes neuronal tolerance to ischemic brain injury.

APETx2对感染后肠易激综合征小鼠内脏敏感性的作用及机制

目的探讨酸敏感离子通道3特异性拮抗剂(APETx2)对感染后肠易激综合征(PI-IBS)小鼠内脏敏感性的调控作用及其机制。方法采用旋毛虫感染NIH小鼠建立PI-IBS模型。通过测量首次排黑便的时间和6 h内收集的粪便颗粒数评估胃肠道运输功能;腹壁回撤反射(AWR)评分评估小鼠内脏敏感性;免疫组织化学法检测结肠组织中降钙素基因相关肽(CGRP)蛋白表达;通过实时定量PCR(qRT-PCR)法检测结肠组织中脑源性神经营养因子(BDNF)、CGRP mRNA表达。蛋白质印迹法(Western blot)检测脑组织中酸敏感离子通道3(ASIC3)、CGRP、瞬时受体电位香草素1(TRPV1)蛋白表达。结果与对照组比较,PI-IBS组首次排黑便时间显著降低,6 h内的粪便颗粒数,AWR评分均显著升高,结肠组织中CGRP蛋白表达显著升高,BDNF、CGRP mRNA显著升高,脑组织中CGRP、ASIC3、TRPV1的蛋白表达显著升高;与PI-IBS组比较,APETx2组首次排黑便时间显著延长,6 h内的粪便颗粒数,AWR评分均显著降低,结肠组织中CGRP蛋白表达显著降低,BDNF、CGRP mRNA表达显著降低,脑组织中CGRP、ASIC3、TRPV1的蛋白表达显著降低,差异均有统计学意义(P<0.05)。结论APETx2可通过下调BDNF、CGRP、ASIC3、TRPV1的表达,减轻PI-IBS小鼠的内脏敏感性并调节胃肠道运动。APETx2可能为治疗IBS提供一个新的治疗选择。

触脑脊液神经元的研究进展

触脑脊液神经元（cerebrospinal fluid-contacting neurons,CSF-cNs）是一种分布于脑室、中央管、脑室周器及脑实质等处与脑脊液接触的特殊神经元。根据分布位置不同可将CSF-cNs分为室管膜上、室管膜下和远位CSF-cNs三类,不同部位的CSF-cNs分泌不同的神经递质。以往研究CSF-cNs多采用脑室注射辣根过氧化物酶标记的霍乱毒素B亚单位（cholera toxin subunit B labeled with horseradish peroxidase,CB-HRP）进行逆行追踪.

ASIC2 Synergizes with TRPV1 in the Mechano-Electrical Transduction of Arterial Baroreceptors

Mechanosensitive ion channels(MSCs)are key molecules in the mechano-electrical transduction of arterial baroreceptors.Among them,acid-sensing ion channel 2(ASIC2)and transient receptor potential vanilloid subfamily member 1(TRPV1)have been studied extensively and documented to play important roles.In this study,experiments using aortic arch-aortic nerve preparations isolated from rats revealed that both ASIC2 and TRPV1 are functionally necessary,as blocking either abrogated nearly all pressure-dependent neural discharge.However,whether ASIC2 and TRPV1 work in coordination remained unclear.So we carried out cell-attached patch-clamp recordings in HEK293T cells co-expressing ASIC2 and TRPV1 and found that inhibition of ASIC2 completely blocked stretch-activated currents while inhibition of TRPV 1 only partially blocked these currents.Immunofluorescence staining of aortic arch-aortic adventitia from rats showed that ASIC2 and TRPV1 are co-localized in the aortic nerve endings,and co-immunoprecipitation assays confirmed that the two proteins form a compact complex in HEK293T cells and in baroreceptors.Moreover,protein modeling analysis,exogenous co-immunoprecipitation assays,and biotin pull-down assays indicated that ASIC2 and TRPV1 interact directly.In summary,our research suggests that ASIC2 and TRPV1 form a compact complex and function synergisti-cally in the mechano-electrical transduction of arterial baroreceptors.The model of synergism between MSCs may have important biological significance beyond ASIC2 and TRPV 1.

Molecular mechanism of inflammatory pain

Chronic inflammatory pain resulting from arthritis, nerve injury and tumor growth is a serious public health issue. One of the major challenges in chronic inflammatory pain research is to develop new pharmacologic treatments with long-term efficacy and few side effects. The mediators released from inflamed sites induce complex changes in peripheral and central processing by directly acting on transducer receptors located on primary sensory neurons to transmit pain signals or indirectly modulating pain signals by activating receptors coupled with G-proteins and second messengers. High local proton concentration(acidosis) is thought to be a decisive factor in inflammatory pain and other mediators such as prostaglandin, bradykinin, and serotonin enhance proton-induced pain. Proton-sensing ion channels [transient receptor potential V1(TRPV1) and the acid-sensing ion channel(ASIC) family] are major receptors for direct excitation of nociceptive sensory neurons in response to acidosis or inflammation.G-protein-coupled receptors activated by prostaglandin, bradykinin, serotonin, and proton modulate functions of TRPV1, ASICs or other ion channels, thus leading to inflammation- or acidosis-linked hyperalgesia. Although detailed mechanisms remain unsolved, clearly different types of pain or hyperalgesia could be due to complex interactions between a distinct subset of inflammatory mediator receptors expressed in a subset of nociceptors. This review describes new directions for the development of novel therapeutic treatments in pain.

电针内关穴对心肌缺血大鼠HIF-1α及酸敏感离子通道基因表达的影响

目的:观察电针内关穴对心肌缺血大鼠缺氧诱导因子(HIF-1α)及酸敏感离子通道(ASIC2、ASIC3)基因表达的影响。方法:SD大鼠45只随机对照方法分为正常组、模型组、内关组、列缺组、非经非穴组,每组10只。异丙肾上腺素造模成功后,分别进行电针治疗。1周后,Realtime RT-PCR法检测各组左心室心肌ASIC2、ASIC3的基因表达,ELISA法检测各组血清HIF-1α含量。结果:电针内关穴可降低心肌缺血大鼠ASIC2、ASIC3基因表达,降低血清中HIF-1α含量,与模型组比较有显著性差异(P<0.01),且优于列缺组与非经非穴组(P<0.01)。结论:电针内关穴可降低血清中HIF-1α含量,下调心肌缺血大鼠ASIC2、ASIC3基因表达,从而抑制酸敏感离子通道开放,有效改善心肌缺血大鼠心肌细胞的损伤。

ASIC1基因SNP_(s)检测及其与史宾格犬胆量性状的关联分析

为了研究史宾格犬酸敏感离子通道1(acid-sensing ion channel 1,ASIC1)基因的多态性及其与胆量性状之间的关系,试验采用DNA测序技术,对166只史宾格犬ASIC1基因的多态性进行研究,并利用SPSS软件中的一般线性模型(general linear model,GLM)分析了ASIC1基因与胆量性状的关系。结果表明:在ASIC1基因外显子2、外显子4和外显子5上各发现了一个单核苷酸多态(single nucleotide polymorphic,SNP)位点,分别为9G>C、102A>C和20G>A;9G>C和20G>A位点属于中度多态,102A>C位点属于低度多态,且这3个位点均不符合Hardy-Weinberg平衡状态;102A>C与胆量评分显著相关(P<0.05),其中AC型和CC型胆量评分显著高于AA型(P<0.05),AC型和CC型之间差异不显著(P>0.05)。笔者发现了一个与史宾格犬胆量性状显著相关的SNP位点,其可作为史宾格犬早期胆量性状的分子标记,用于史宾格犬早期胆量性状的分子标记辅助选择。