Radiosynthesis and biodistribution of a histamine H3 receptor antagonist 4-[3-(4-piperidin-1-yl-but-1-ynyl)-[11C]benzyl]-morpholine: evaluation of a potential PET ligand.

The potent histamine H(3) receptor antagonist JNJ-10181457 (1) was successfully labeled with (11)C in a novel one-pot reaction sequence, with high chemical yield (decay-corrected yield, 28+/-8%) and high specific radioactivity (56+/-26 GBq/mumol). The binding of [(11)C]1 to H(3) receptors was studied in vitro in rat brain and in vivo in rats and mice. The in vitro binding of [(11)C]1 in rat coronal brain slices showed high binding in the striatum, and this binding was blocked by histamine and by two known H(3) antagonists, JNJ-5207852 (2) and unlabeled Compound (1), in a concentration-dependent manner.

Synthesis and evaluation of radiolabeled analogs of the antidepressant drug zimelidine as potential SPECT-ligands for the serotonin transporter.

Z-3-(4-bromophenyl)-N,N-dimethyl-3-(3-pyridinyl)-2-propen-1-amine or zimelidine (ZIM) and its first metabolite nor-zimelidine, were radioiodinated via a nonisotopic exchange, using the Cu(I)-assisted nucleophilic labeling method. To evaluate their potential as SPECT ligands for the serotonin transporter (SERT), the biodistribution of both ligands was determined and pretreatment "blocking" studies performed. Both radioligands demonstrated a good brain penetration of 0.