In rodents, gene‐expression, neuronal tuning, connectivity and neurogenesis studies have postulated that the dorsal, the intermediate and the ventral hippocampal formation (HF) are distinct entities. These findings are underpinned by behavioral studies showing a dissociable role of dorsal and ventral HF in learning, memory, stress and emotional processing. However, up to now, the molecular basis of such differences in relation to discrete boundaries is largely unknown. Therefore, we analyzed binding site densities for glutamatergic AMPA, NMDA, kainate and mGluR_2/3, GABAergic GABA_A (including benzodiazepine binding sites), GABA_B, dopaminergic D_1/5 and noradrenergic α₁ and α₂ receptors as key modulators for signal transmission in hippocampal functions, using quantitative in vitro receptor autoradiography along the dorsal‐ventral axis of the mouse HF. Beside general different receptor profiles of the dentate gyrus (DG) and Cornu Ammonis fields (CA1, CA2, CA3, CA4/hilus), we detected substantial differences between dorsal, intermediate and ventral subdivisions and individual layers for all investigated receptor types, except GABA_B. For example, striking higher densities of α₂ receptors were detected in the ventral DG, while the dorsal DG possesses higher numbers of kainate, NMDA, GABA_A and D_1/5 receptors. CA1 dorsal and intermediate subdivisions showed higher AMPA, NMDA, mGluR_2/3, GABA_A, D_1/5 receptors, while kainate receptors are higher expressed in ventral CA1, and noradrenergic α₁ and α₂ receptors in the intermediate region of CA1. CA2 dorsal was distinguished by higher kainate, α₁ and α₂ receptors in the intermediate region, while CA3 showed a more complex dissociation. Our findings resulted not only in a clear segmentation of the mouse hippocampus along the dorsal‐ventral axis, but also provides insights into the neurochemical basis and likely associated physiological processes in hippocampal functions. Therein, the presented data has a high impact for future studies modeling and investigating dorsal, intermediate and ventral hippocampal dysfunction in relation to neurodegenerative diseases or psychiatric disorders.

中文翻译：

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基于谷氨酸能、GABA能和儿茶酚胺能受体密度的小鼠海马体沿背腹轴的新边界和分离。

在啮齿动物中，基因表达、神经元调谐、连接性和神经发生研究假设背侧、中间和腹侧海马形成 (HF) 是不同的实体。这些发现得到了行为研究的支持，这些研究表明背侧和腹侧 HF 在学习、记忆、压力和情绪处理中具有可分离的作用。然而，到目前为止，与离散边界相关的这种差异的分子基础在很大程度上是未知的。因此，我们分析了谷氨酸能 AMPA、NMDA、红藻氨酸和 mGluR _2/3、GABA 能 GABA _A（包括苯二氮卓结合位点）、GABA _B、多巴胺能 D _1/5和去甲肾上腺素能 α ₁和 α _{2 的}结合位点密度受体作为海马功能信号传输的关键调节剂，使用沿小鼠 HF 背腹轴的定量体外受体放射自显影。除了齿状回 (DG) 和 Cornu Ammonis 场 (CA1、CA2、CA3、CA4/门) 的一般不同受体概况之外，我们还检测到所有研究的受体类型的背侧、中间和腹侧细分以及各个层之间的显着差异，除了 GABA_乙。例如，在腹侧 DG 中检测到显着更高密度的 α ₂受体，而背侧 DG 具有更高数量的红藻氨酸、NMDA、GABA _A和 D _1/5受体。CA1 背侧和中间细分显示出更高的 AMPA、NMDA、mGluR _2/3, GABA _A , D _1/5受体，而红藻氨酸受体在腹侧 CA1 中表达较高，而去甲肾上腺素能 α ₁和 α ₂受体在 CA1 的中间区域表达。CA2 背侧以较高的红藻氨酸、α ₁和 α _{2 为特征}受体在中间区域，而 CA3 表现出更复杂的解离。我们的研究结果不仅导致小鼠海马体沿背腹轴的清晰分割，而且还提供了对海马功能中神经化学基础和可能相关生理过程的见解。其中，所提供的数据对未来的研究建模和调查与神经退行性疾病或精神疾病相关的背侧、中间和腹侧海马功能障碍具有重大影响。