Brann M R
Biochem Biophys Res Commun. 1985 Dec 31;133(3):1181-6. doi: 10.1016/0006-291x(85)91261-6.
Target size analysis was used to compare the sizes of serotonin-S2 and dopamine-D2 receptors in rat brain membranes. The sizes of these receptors were standardized by comparison with the muscarinic receptor, a receptor of known size. The number of serotonin-S2 receptors labeled with (3H)ketanserin or (3H)spiperone in frontal cortex decreased as an exponential function of radiation dose, and receptor affinity was not affected. The number of dopamine-D2 receptors labeled with (3H)spiperone in striatum also decreased as an exponential function of radiation dose, and D2 and S2 receptors were equally sensitive to radiation. In both striatum and frontal cortex, the number of muscarinic receptors labeled with (3H)QNB decreased as an exponential function of radiation dose, and were much less sensitive to radiation than S2 and D2 receptors. These data indicate that in rat brain membranes, S2 and D2 receptors are of similar size, and both molecules are much larger than the muscarinic receptor.
采用靶标大小分析方法比较大鼠脑膜中5-羟色胺-S2受体和多巴胺-D2受体的大小。通过与已知大小的毒蕈碱受体比较，对这些受体的大小进行标准化。额叶皮质中用（3H）酮色林或（3H）螺哌隆标记的5-羟色胺-S2受体数量随辐射剂量呈指数函数减少，且受体亲和力未受影响。纹状体中用（3H）螺哌隆标记的多巴胺-D2受体数量也随辐射剂量呈指数函数减少，且D2和S2受体对辐射同样敏感。在纹状体和额叶皮质中，用（3H）QNB标记的毒蕈碱受体数量随辐射剂量呈指数函数减少，且对辐射的敏感性远低于S2和D2受体。这些数据表明，在大鼠脑膜中，S2和D2受体大小相似，且这两种分子都比毒蕈碱受体大得多。
