Hall H, Halldin C, Sedvall G
Department of Psychiatry and Psychology, Karolinska Hospital, Stockholm, Sweden.
Neurosci Lett. 1992 Feb 17;136(1):79-82. doi: 10.1016/0304-3940(92)90652-n.
The effects of the stable GTP analogue Gpp(NH)p (5'-guanylyl imido diphosphate) were examined on in vitro [3H]raclopride binding to dopamine D2 receptors in preparations from post mortem human brains. The estimated number of receptors in the brain was 29% and 38% higher in putamen and accumbens, respectively, when determined in the presence of Gpp(NH)p as compared to its absence. The interaction of agonists was biphasic confirming the two affinity state model of the receptor--G-protein complex. The addition of Gpp(NH)p to the assay abolished the two site competition of apomorphine with [3H]raclopride binding in both regions studied. The non-specific binding at high concentrations of apomorphine was not significantly affected by the addition of Gpp(NH)p, indicating that only the specific binding of [3H]raclopride to the dopamine D2 receptor is increased.
研究了稳定的GTP类似物Gpp(NH)p（5'-鸟苷酰亚胺二磷酸）对死后人类大脑组织中体外[3H]雷氯必利与多巴胺D2受体结合的影响。与不存在Gpp(NH)p时相比，在存在Gpp(NH)p的情况下测定时，壳核和伏隔核中大脑受体的估计数量分别高出29%和38%。激动剂的相互作用是双相的，证实了受体 - G蛋白复合物的两种亲和力状态模型。在测定中加入Gpp(NH)p消除了阿扑吗啡与[3H]雷氯必利在两个研究区域结合的双位点竞争。加入Gpp(NH)p对高浓度阿扑吗啡时的非特异性结合没有显著影响，表明只有[3H]雷氯必利与多巴胺D2受体的特异性结合增加。
