Foddi M C, Mennini T
Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
Neurosci Lett. 1997 Jul 18;230(2):105-8. doi: 10.1016/s0304-3940(97)00484-9.
[125I][Tyr14]Orphanin binds to a number of saturable non-interacting binding sites in rat brain cortical membrane preparations, with a density of 510 fmol/mg protein and affinity 0.9 nM. This high affinity, saturable [125I][Tyr14]orphanin binding was not inhibited by leu-enkephalin and by other ligands for opiate and neurotransmitter receptors both in membrane preparations and brain sections. In rat brain sections, the highest density of binding was found in the outer and medial cortical layers, subiculum, hippocampus and nucleus accumbens; intermediate binding densities were found in the inner cortical layer, pontine nuclei, thalamus and hypothalamus. Very low specific binding was seen in the cerebellum and striatum, according to the described distribution of ORL1 transcripts. These results suggest that [125I][Tyr14] orphanin binding in rat brain occurs to the described ORL1 receptor.
[125I][酪氨酰14]孤啡肽与大鼠脑皮层膜制剂中的多个可饱和、非相互作用的结合位点结合，密度为510飞摩尔/毫克蛋白，亲和力为0.9纳摩尔。这种高亲和力、可饱和的[125I][酪氨酰14]孤啡肽结合在膜制剂和脑切片中均不受亮氨酸脑啡肽以及其他阿片和神经递质受体配体的抑制。在大鼠脑切片中，结合密度最高的部位是外侧和内侧皮层、海马下托、海马体和伏隔核；在内侧皮层、脑桥核、丘脑和下丘脑发现了中等结合密度。根据所描述的ORL1转录本分布，在小脑和纹状体中观察到极低的特异性结合。这些结果表明，大鼠脑中[125I][酪氨酰14]孤啡肽的结合发生在所描述的ORL1受体上。
