Evidence for differential cortical input to direct pathway versus indirect pathway striatal projection neurons in rats
Evidence for differential cortical input to direct pathway versus indirect pathway striatal projection neurons in rats
复制标题
大鼠直接通路与间接通路纹状体投射神经元皮质输入差异的证据
DOI：
10.1523/jneurosci.1990-04.2004
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发表时间：
2004-09-22
影响因子：
5.3
通讯作者：
Reiner, A
中科院分区：
文献类型：
--
作者：
Lei, WL;Jiao, Y;Reiner, A
皮质纹状体神经元的两种主要类型是仅投射到端脑内的神经元（IT型），其纹状体内末端的平均直径为0.41 μ m，以及将其主要轴突发送到锥体束并具有侧支投射到纹状体的神经元（PT型），其纹状体内末端的平均直径为0.82 μ m。我们使用三种方法来检查是否两种纹状体投射神经元类型（纹状体黑质直接通路与纹状体体间接通路）在其输入不同的IT型和PT型神经元。首先，我们逆行标记一个纹状体投射神经元类型或其他生物素化葡聚糖胺（BDA）3000分子量。我们发现，终端不对称axosinous接触与striatonigral神经元的平均直径为0.43妈妈，而那些不对称axosinous接触与striatopallidal神经元为0.69妈妈。第二，我们优先免疫标记的D-1多巴胺受体的纹状体黑质神经元或D-2多巴胺受体的striatopallidal神经元，并发现轴棘末梢有一个较小的平均尺寸（0.45妈妈）D-1+棘比D-2+棘（0.61妈妈）。最后，我们结合选择性BDA标记的IT型或PT型终端与免疫标记的D-1或D-2，并发现，IT型终端是常见的PT型D-1+棘上的两倍，而PT型终端是常见的IT型D-2+棘上的四倍。这些不同的结果表明，striatonigral神经元优先接收输入从IT型皮质神经元，而striatopallidal神经元接收更多的输入从PT型皮质神经元。这种不同的皮质连接性可能会进一步发挥直接和间接通路在促进所需运动和抑制不需要的运动方面的作用。
The two main types of corticostriatal neurons are those that project only intratelencephalically (IT-type), the intrastriatal terminals of which are 0.41 mum in mean diameter, and those that send their main axon into pyramidal tract and have a collateral projection to striatum (PT-type), the intrastriatal terminals of which are 0.82 mum in mean diameter. We used three approaches to examine whether the two striatal projection neuron types (striatonigral direct pathway vs striatopallidal indirect pathway) differ in their input from IT-type and PT-type neurons. First, we retrogradely labeled one striatal projection neuron type or the other with biotinylated dextran amine (BDA)3000 molecular weight. We found that terminals making asymmetric axospinous contact with striatonigral neurons were 0.43 mum in mean diameter, whereas those making asymmetric axospinous contact with striatopallidal neurons were 0.69 mum. Second, we preferentially immunolabeled striatonigral neurons for D-1 dopamine receptors or striatopallidal neurons for D-2 dopamine receptors and found that axospinous terminals had a smaller mean size (0.45 mum) on D-1+ spines than on D-2+ spines (0.61 mum). Finally, we combined selective BDA labeling of IT-type or PT-type terminals with immunolabeling for D-1 or D-2, and found that IT-type terminals were twice as common as PT-type on D-1+ spines, whereas PT-type terminals were four times as common as IT-type on D-2+ spines. These various results suggest that striatonigral neurons preferentially receive input from IT-type cortical neurons, whereas striatopallidal neurons receive greater input from PT-type cortical neurons. This differential cortical connectivity may further the roles of the direct and indirect pathways in promoting desired movements and suppressing unwanted movements, respectively.