Young W S, Kuhar M J
Proc Natl Acad Sci U S A. 1980 Mar;77(3):1696-700. doi: 10.1073/pnas.77.3.1696.
[3H]WB-4101 and p-[3H]aminoclonidine were used for light microscopic autoradiographic localization of alpha 1 and alpha 2 adrenergic receptors, respectively, in the rat brain. The binding of these ligands to slide-mounted tissue sections had all of the characteristics associated with alpha 1 and alpha 2 receptors. It was saturable with appropriate kinetic constants and was blocked only by other alpha-adrenergic drugs with the appropriate potency. Autoradiographic studies revealed a distribution of alpha-adrenergic receptors throughout the nervous system. Certain areas had elevated levels. These included parts of the olfactory bulb and nucleus, parts of the cerebral cortex and dentate gyrus, the more medial portions of the hypothalamus and thalamus, the locus ceruleus and nucleus tractus solitarii, and parts of the spinal cord. In certain areas, the distribution of alpha 1 and alpha 2 receptors was markedly different. These results provide some rational basis for the observed actions of alpha-adrenergic drugs on the central nervous system. For example, the finding of high densities of alpha 2 receptors in the nucleus tractus solitarii is most likely related to its antihypertensive action. The observed codistribution of alpha 2 receptors with opiate receptors would provide an explanation of the observation that alpha 2 agonists block opiate withdrawal. The results are also discussed in relationship to the anatomy of catecholamine systems in the brain.
[3H]WB - 4101和对[3H]氨基可乐定分别用于大鼠脑内α1和α2肾上腺素能受体的光学显微镜放射自显影定位。这些配体与载玻片上的组织切片的结合具有与α1和α2受体相关的所有特征。它具有适当的动力学常数，表现出饱和性，并且仅被其他具有适当效力的α - 肾上腺素能药物阻断。放射自显影研究揭示了α - 肾上腺素能受体在整个神经系统中的分布。某些区域的受体水平升高。这些区域包括嗅球和嗅核的部分区域、大脑皮层和齿状回的部分区域、下丘脑和丘脑的内侧部分、蓝斑和孤束核以及脊髓的部分区域。在某些区域，α1和α2受体的分布明显不同。这些结果为α - 肾上腺素能药物对中枢神经系统的观察作用提供了一些合理依据。例如，在孤束核中发现高密度的α2受体很可能与其降压作用有关。观察到的α2受体与阿片受体的共分布可以解释α2激动剂阻断阿片类药物戒断的现象。还结合脑内儿茶酚胺系统的解剖结构对结果进行了讨论。
