AUTORADIOGRAPHIC COMPARISON OF [I-125] EPIDEPRIDE AND [I-125] NCQ-298BINDING TO HUMAN BRAIN EXTRASTRIATED DOPAMINE-RECEPTORS

Extrastriatal D-2-dopamine receptors can be visualised in the monkey a nd human brain using the benzamides [C-11] and [Br-76]FLB 457 in PET a nd [I-123]epidepride in SPECT but not with the salicylamide analogues [Br-76]FLB 463 and [I-123]NCQ 298. To clarify the background for the d ifferences in binding seen in vivo, we have compared the in vitro bind ing of [I-125]epidepride and [I-125]NCR 298, using human whole hemisph ere autoradiography. The images obtained with any radioligand showed d etailed distribution with very dense binding in the putamen and the ca udate nucleus and with the same detailed extrastriatal distribution. T hus, the divergent results obtained in vivo cannot be explained by dif ferent binding properties of the extrastriatal receptors. (C) 1997 Els evier Science Inc.