Zilles K, Gross G, Schleicher A, Schildgen S, Bauer A, Bahro M, Schwendemann G, Zech K, Kolassa N
Institute 1 of Anatomy, Univerity of Cologne, F.R.G.
Neuroscience. 1991;40(2):307-20. doi: 10.1016/0306-4522(91)90122-5.
The distributions of the alpha 1-adrenoceptor and its subtypes (alpha 1A and alpha 1B) in human and rat hippocampus are analysed by quantitative receptor autoradiography. alpha 1-Adrenoceptors are labelled by [3H]prazosin. The alpha 1A subtype is visualized by [3H]prazosin after irreversible blockade of alpha 1B adrenoceptors with chloroethylclonidine or directly by [3H]5-methyl-urapidil. The alpha 1B subtype is investigated by [3H]prazosin binding in the presence of the alpha 1A antagonist 5-methyl-urapidil. Considerable differences in the regional and laminar patterns of alpha 1-adrenoceptors are found between rat and human hippocampi. The rat hippocampus is characterized by a low overall density and a rather homogeneous regional and laminar distribution. This is in contrast to the human pattern, which shows a much higher overall level of alpha 1 receptor density and a restriction of alpha 1 receptors to the CA3 region of Ammon's horn and the dentate gyrus. Moreover, alpha 1A and alpha 1B receptors of the human hippocampus are differentially distributed with the alpha 1A subtype concentrated in the hilus and lucidum layer of CA3, and the alpha 1B subtype concentrated in the molecular layer of the dentate gyrus. Additionally, the distribution of alpha 1 receptors is compared with the distribution of 5-hydroxytryptamine 1A receptors. The subtype specific pattern is correlated with the distribution of glutamatergic systems in the human (but not in the rat) hippocampus. alpha 1A Receptor localization coincides with the target area of the mossy fibre system, and alpha 1B receptors are preferentially localized in the target area of the hippocampal associational fibres and partly of the perforant pathway. This result points to possible interactions between noradrenaline- and glutamate-mediated neurotransmission differentiated by topographically segregated alpha 1-adrenoceptor subtypes.
采用定量受体放射自显影法分析人及大鼠海马中α1 - 肾上腺素能受体及其亚型（α1A和α1B）的分布。α1 - 肾上腺素能受体用[3H]哌唑嗪标记。在用氯乙可乐定不可逆阻断α1B肾上腺素能受体后，用[3H]哌唑嗪可显示α1A亚型，或直接用[3H]5 - 甲基 - 乌拉地尔显示。α1B亚型通过在α1A拮抗剂5 - 甲基 - 乌拉地尔存在下的[3H]哌唑嗪结合来研究。在大鼠和人海马之间，发现α1 - 肾上腺素能受体的区域和层状模式存在显著差异。大鼠海马的特点是总体密度低，区域和层状分布相当均匀。这与人的模式形成对比，人的模式显示α1受体密度总体水平高得多，且α1受体局限于海马角的CA3区和齿状回。此外，人海马中的α1A和α1B受体分布不同，α1A亚型集中在CA3的门区和透明层，α1B亚型集中在齿状回的分子层。此外，还将α1受体的分布与5 - 羟色胺1A受体的分布进行了比较。亚型特异性模式与人（而非大鼠）海马中谷氨酸能系统的分布相关。α1A受体定位与苔藓纤维系统的靶区一致，α1B受体优先定位于海马联合纤维以及部分穿通通路的靶区。这一结果表明，由地形学上分离的α1 - 肾上腺素能受体亚型区分的去甲肾上腺素和谷氨酸介导的神经传递之间可能存在相互作用。
