Köhler C, Ericson H, Radesäter A C
Preclinical Research Department, Astra Research Centre, Södertälje, Sweden.
Neurosci Lett. 1991 May 27;126(2):107-9. doi: 10.1016/0304-3940(91)90530-7.
The distribution of dopamine (DA) D1 and D2 receptors in the hippocampal region was studied using in vitro receptor autoradiography with 125I-SCH 23982 and 125I-NCQ 298, respectively. The specific binding of both ligands indicated the existence of D1 as well as D2 receptors in the rat hippocampal region. A closer analysis revealed, however, a different laminar distribution of the two receptor subtypes: layers with a high density of one DA receptor subtype had low density of the other. Thus, in the entorhinal cortex, which contained the highest densities of both subtypes, the following pattern was seen. Layers 2, 4, 5 and 6 had high densities of D1 receptors and low densities of D2 receptors while layers 1 and 3 had high densities of D2 receptors and low densities of D1 receptors. The parasubiculum contained D1 receptors but not D2 receptors and the presubiculum had D2 receptors in layer 2 but few D1 receptors. Similar patterns were recorded in Ammon's horn: the part of stratum lacunosum-moleculare which was rich in D1 was poor in D2 receptors. The interdigitating laminar distribution of D1 and D2 receptors suggests that the effects of DA are mediated via D1 and D2 receptors located at different levels along the intrinsic hippocampal circuit.
分别使用125I-SCH 23982和125I-NCQ 298通过体外受体放射自显影技术研究了海马区多巴胺（DA）D1和D2受体的分布。两种配体的特异性结合表明大鼠海马区存在D1和D2受体。然而，进一步分析发现这两种受体亚型的层状分布不同：一种DA受体亚型高密度的层，另一种受体亚型的密度则低。因此，在两种亚型密度均最高的内嗅皮质中，观察到以下模式。第2、4、5和6层D1受体密度高，D2受体密度低，而第1和3层D2受体密度高，D1受体密度低。副海马体含有D1受体但不含D2受体，而海马旁回在第2层有D2受体，但D1受体很少。在海马结构中也记录到了类似的模式：富含D1的腔隙分子层部分D2受体较少。D1和D2受体的交叉层状分布表明，多巴胺的作用是通过位于海马固有回路不同水平的D1和D2受体介导的。
