In vivo evaluation of 4-[I-123]iodo-N-{2-[4-(6-trifluoromethyl-2-pyridinyl)-1-piperazinyl]ethyl}benzamide, a potential SPECT radioligand for the 5-HT1A receptor

4-[I-123] Iodo-N-{2-[4-(6-trifluoromethyl-2-pyridinyl)-1-piperazinyl]ethyl} benzamide ((1) under bar.I-123), a potential SPECT 5-HT1A radioligand, was evaluated in vivo in rats. Biodistribution studies were performed leading t o a % ID in the brain of 0.22 at 5 min p.i. No significant differences in % ID/g tissue of the different isolated brain regions (hippocampus, hypothal amus, striatum, cortex and cerebellum) could be demonstrated. Blocking expe riments with 8-OH-DPAT, WAY100635 and ketanserin could not show any signifi cant change in tracer uptake in the isolated brain regions. These data sugg est that uptake in the brain does not represent binding of (1) under bar.I- 123 to the 5-HT1A receptor. (C) 2001 Elsevier Science Inc. All rights reser ved.