Hill J M, Lesniak M A, Pert C B, Roth J
Neuroscience. 1986 Apr;17(4):1127-38. doi: 10.1016/0306-4522(86)90082-5.
The binding of 125I-labeled insulin in thin sections of frozen fresh rat brain (95% specific binding) was shown using autoradiography. By several criteria including structure-activity relationship analysis, the brain insulin receptors were qualitatively indistinguishable from insulin receptors previously characterized on brain and other more typical target tissues and distinct from receptors for the insulin-like growth factors. The 125I-labeled insulin binding sites in brain formed a distinct pattern with high levels of binding in all olfactory areas and in closely related limbic regions. Binding was also prominent in the neocortex and the accessory motor areas of the basal ganglia and the cerebellum. Among ancillary brain structures only the choroid plexus demonstrated a high density of insulin receptors. When insulin receptors were located on cortical or laminated structures, the highest binding occurred in the superficial ("molecular" or "plexiform") layer, i.e. the layer which receives afferent input and/or is rich in the dendritic branches of principal neurons (e.g. external plexiform layer of the olfactory bulb and the molecular layer of the dentate gyrus). The enrichment of insulin receptors in the olfactory and limbic systems, which is a characteristic feature of other known neuropeptides, in addition to their prevalence in the strata occupied by the dendritic fields of principle neurons, suggests a neuromodulatory function for insulin in the brain.
利用放射自显影技术显示了125I标记的胰岛素在新鲜冰冻大鼠脑薄片中的结合情况（特异性结合率为95%）。通过包括构效关系分析在内的多项标准，脑胰岛素受体在性质上与先前在脑及其他更典型靶组织中所鉴定的胰岛素受体并无差异，且与胰岛素样生长因子的受体不同。脑中125I标记的胰岛素结合位点形成了一种独特的模式，在所有嗅觉区域及密切相关的边缘区域结合水平较高。在新皮层、基底神经节的辅助运动区以及小脑中结合也很显著。在脑的附属结构中，只有脉络丛显示出高密度的胰岛素受体。当胰岛素受体位于皮质或分层结构上时，则在浅表（“分子”或“丛状”）层出现最高结合，即接受传入输入和/或富含主要神经元树突分支的层（如嗅球的外丛状层和齿状回的分子层）。胰岛素受体在嗅觉和边缘系统中的富集，这是其他已知神经肽的一个特征，除了它们在主要神经元树突场占据的层中普遍存在外，提示胰岛素在脑中具有神经调节功能。
