Rodent habenulo-interpeduncular pathway expresses a large variety of uncommon nAChR subtypes, but only the alpha3beta4* and alpha3beta3beta4* subtypes mediate acetylcholine release.
Rodent habenulo-interpeduncular pathway expresses a large variety of uncommon nAChR subtypes, but only the alpha3beta4* and alpha3beta3beta4* subtypes mediate acetylcholine release.
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DOI：
10.1523/jneurosci.5121-08.2009
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发表时间：
2009-02-18
期刊：
影响因子：
--
通讯作者：
Gotti C
中科院分区：
文献类型：
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作者：
Grady SR;Moretti M;Zoli M;Marks MJ;Zanardi A;Pucci L;Clementi F;Gotti C
最近的研究表明，存在于缰核-脚间（Hb-IPn）系统中的神经元烟碱受体（nAChR）可以调节成瘾药物的增强作用和尼古丁的抗焦虑作用。 Hb 和 IPn 神经元表达大多数 nAChR 亚基的 mRNA，因此很难确定功能受体的亚基组成。我们使用在大鼠、野生型 (+/+) 和 β2 敲除 (−/−) 小鼠中进行的免疫沉淀和免疫纯化研究来确定 Hb 和 IPn 含有显着的 nAChR 受体 β2* 和 β4* 群体（每种受体都是异质的）。 β4* nAChR 在 IPn 中表达更高。我们还鉴定了新的天然亚型（α2β2*、α4β3β2*α3β3β4*、α6β3β4*）。我们对从 +/+ 和 α2、α4、α5、α6、α7、β2、β3 和 β4−/− 小鼠获得的 IPn 突触体的研究表明，只有 α3β4 和 α3β3β4 亚型促进乙酰胆碱 (ACh) 释放。 β3−/− 小鼠的配体结合、免疫沉淀和蛋白质印迹研究表明，在这些小鼠的 IPn 中，ACh 释放和 α3β4* 受体伴随减少，而 Hb 中的受体数量保持不变。我们认为，在缰核胆碱能神经元中，β3 亚基可能对于将 α3β4* 亚型从内侧缰核 (MHb) 转运到 IPn 很重要。总体而言，这些研究强调了 Hb-IPn 系统中存在大量不常见的 nAChR 亚型，并确定了从 Hb 转运并在 IPn 中高度富集的 α3β4 和 α3β3β4 作为调节 IPn 中 ACh 释放的亚型。
Recent studies suggest that the neuronal nicotinic receptors (nAChRs) present in the habenulo-interpeduncular (Hb-IPn) system can modulate the reinforcing effect of addictive drugs and the anxiolytic effect of nicotine. Hb and IPn neurons express mRNAs for most nAChR subunits thus making it difficult to establish the subunit composition of functional receptors. We used immunoprecipitation and immunopurification studies performed in rat, and wildtype (+/+) and β2 knockout (−/−) mice to establish that the Hb and IPn contain significant β2* and β4* populations of nAChR receptors (each of which is heterogeneous). The β4* nAChR are more highly expressed in the IPn. We also identified novel native subtypes (α2β2*, α4β3β2*α3β3β4*, α6β3β4*). Our studies on IPn synaptosomes obtained from +/+ and α2, α4, α5, α6, α7, β2, β3 and β4−/− mice, show that only the α3β4 and α3β3β4 subtypes facilitate acetylcholine (ACh) release. Ligand binding, immunoprecipitation and Western blotting studies in β3−/− mice showed that in the IPn of these mice there is a concomitant reduction of ACh release and α3β4* receptors, while the receptor number remains the same in the Hb. We suggest that in habenular cholinergic neurons the β3 subunit may be important for transporting the α3β4* subtype from the medial habenula (MHb) to the IPn. Overall, these studies highlight the presence of a wealth of uncommon nAChR subtypes in the Hb-IPn system and identify α3β4 and α3β3β4, transported from the Hb and highly enriched in the IPn, as the subtypes modulating ACh release in the IPn.