Differential expression of muscarinic acetylcholine receptors across excitatory and inhibitory cells in visual cortical areas V1 and V2 of the macaque monkey
Differential expression of muscarinic acetylcholine receptors across excitatory and inhibitory cells in visual cortical areas V1 and V2 of the macaque monkey
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DOI：
10.1002/cne.21096
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发表时间：
2006-11-01
影响因子：
2.5
通讯作者：
Aoki, Chiye
中科院分区：
文献类型：
--
作者：
Disney, Anita A.;Domakonda, Kunal V.;Aoki, Chiye
胆碱能神经调节是一种注意力方面的候选机制，是复杂的，尚未得到充分理解。由于结构限制了功能，因此定量解剖结构是减少这种挑战性问题的宝贵工具。我们的目标是确定M1和M2毒蕈碱乙酰胆碱受体（MACHR）在早期视觉皮层中的抑制性与兴奋性神经元表达的程度。为此，将猕猴的V1和v2标记为γ-氨基丁酸（GABA）和ML或M2 MACHR。在GABA免疫反应性（IR）神经元中，V1中的61％为M1 ACHR-IR，V2为63％，而V1为28％，V2中的43％为M2 ACHR-IR。在V1中，两个MACHR均以不到10％的兴奋性神经元表示。但是，在V2中，MACHR-IT兴奋性神经元的种群至少是V1中观察到的两倍。我们还检查了电子显微镜下V1区域第2和3层的ML和M2 ACHR免疫反应性，并发现证据表明GABA能神经元将MACHR定位在SOMA中，而谷氨酸能神经元在树突中更强烈地表达了MACHR。轴突和末端标记通常很弱。这些数据代表了任何物种皮层中ML和M2 ACHR表达的首次定量解剖研究。此外，跨V1/V2边界的兴奋性神经元中的表达增加可能为观察到的观察提供了神经基础，即注意力效应通过从区域V1到V2到V2到V4及以后的视觉途径增强强度。
Cholinergic neuromodulation, a candidate mechanism for aspects of attention, is complex and is not well understood. Because structure constrains function, quantitative anatomy is an invaluable tool for reducing such a challenging problem. Our goal was to determine the extent to which m1 and m2 muscarinic acetylcholine receptors (mAChRs) are expressed by inhibitory vs. excitatory neurons in the early visual cortex. To this end, V1 and V2 of macaque monkeys were immunofluorescently labelled for gamma-aminobutyric acid (GABA) and either ml or m2 mAChRs. Among the GABA-immunoreactive (ir) neurons, 61% in V1 and 63% in V2 were m1 AChR-ir, whereas 28% in V1 and 43% in V2 were m2 AChR-ir. In V1, both mAChRs were expressed by fewer than 10% of excitatory neurons. However, in V2, the population of mAChR-it excitatory neurons was at least double that observed in V1. We also examined ml and m2 AChR immunoreactivity in layers 2 and 3 of area V1 under the electron microscope and found evidence that GABAergic neurons localize mAChRs to the soma, whereas glutamatergic neurons expressed mAChRs more strongly in dendrites. Axon and terminal labelling was generally weak. These data represent the first quantitative anatomical study of ml and m2 AChR expression in the cortex of any species. In addition, the increased expression in excitatory neurons across the V1/V2 border may provide a neural basis for the observation that attentional effects gain strength up through the visual pathway from area V1 through V2 to V4 and beyond.