Adams Monique R, Nikkel Arthur L, Donnelly-Roberts Diana L, Watt Andrew T, Johnston Joseph F, Cowsert Lex M, Butler Mandeline, Kroeger Paul E, Frost Leigh, Curzon Peter, Decker Michael W, Bitner Robert Scott
Department R4N5, Bldg AP9A, Abbott Laboratories/Neuroscience, 100 Abbott Park Road, Abbott Park, IL 60064-6115, USA.
Brain Res Mol Brain Res. 2004 Oct 22;129(1-2):67-79. doi: 10.1016/j.molbrainres.2004.06.019.
In the mammalian central nervous system (CNS), a family of alpha and beta subunits (alpha2-7, beta2-4) assemble to form both hetero- and homopentameric neuronal nicotinic acetylcholine receptors (nAChRs). In contrast to alpha4beta2 and alpha7, the predominant brain subtypes, far less is known regarding the functional expression and significance of alpha3-containing nAChRs in the CNS. In trying to better understand the role alpha3 in the CNS, an antisense knockdown strategy was utilized in the present studies. Specifically, Isis 106567 was identified out of 80 antisense oligonucleotides (aONs) designed and screened for their ability to reduce alpha3 mRNA expression in PC-12 cells. In addition to reducing alpha3 mRNA by greater than 75%, Isis 106567 attenuated nicotine-induced calcium influx in alpha3-expressing F11 cells. In vivo studies revealed significant reduction of alpha3 mRNA levels in both thalamus and medial habenula, regions known to express alpha3, following continuous (7 days) intracerebroventricular (i.c.v.) infusion of Isis 106567 in rats. Consistent with functional alpha3 knockdown, epibatidine-induced c-Fos expression in the medial habenula was attenuated in aON-treated rats. Known physiological responses elicited by epibatidine, such as hypothermia and micturition, were not affected by alpha3 aON treatment. However, the incidence of epibatidine-induced seizures was reduced in alpha3-antisense aON-treated rats, suggesting that alpha3 may be involved in mediating seizures produced by the nAChR agonist. Results of our studies suggest that Isis 106567 may be a useful in vivo tool for characterizing the functional significance of alpha3 expression in the CNS.
在哺乳动物的中枢神经系统（CNS）中，一组α和β亚基（α2 - 7，β2 - 4）组装形成异源和同源五聚体神经元烟碱型乙酰胆碱受体（nAChRs）。与主要的脑亚型α4β2和α7不同，关于含α3的nAChRs在中枢神经系统中的功能表达和意义所知甚少。为了更好地理解α3在中枢神经系统中的作用，本研究采用了反义敲低策略。具体而言，在设计并筛选的80种反义寡核苷酸（aONs）中，Isis 106567被鉴定出具有降低PC - 12细胞中α3 mRNA表达的能力。除了将α3 mRNA降低75%以上外，Isis 106567还减弱了尼古丁诱导的α3表达的F11细胞中的钙内流。体内研究表明，在大鼠连续（7天）脑室内（i.c.v.）注入Isis 106567后，已知表达α3的丘脑和内侧缰核中的α3 mRNA水平显著降低。与功能性α3敲低一致，在接受aON处理的大鼠中，依博加因诱导的内侧缰核中c - Fos表达减弱。依博加因引发的已知生理反应，如体温过低和排尿，不受α3 aON处理的影响。然而，在接受α3反义aON处理的大鼠中，依博加因诱导的癫痫发作发生率降低，这表明α3可能参与介导nAChR激动剂产生的癫痫发作。我们的研究结果表明，Isis 106567可能是一种用于表征α3在中枢神经系统中表达的功能意义的有用体内工具。
