Synthesis of an I-123 analog of A-85380 and preliminary SPECT imaging of nicotinic receptors in baboon.
A radiosynthetic method to prepare the nicotinic acetylcholine receptor radioligand (S)-5-[123I]iodo-3-(2-azetidinylmethoxy)pyridine, 5-IA, has been developed. The two-step sequence produced [123I]-5-IA in high radiochemical yield (52%), high radiochemical purity (98%), and high specific radioactivities (> 8,500 mCi/mumol). Preliminary single photon emission computed tomography studies with [123I]-5-IA in baboon demonstrated the appropriate regional localization for a high-affinity nicotinic radioprobe (thalamus > frontal cortex > cerebellum). Pretreatment with cytisine blocked [123I]-5-IA uptake in all brain regions (78-59% reduction), demonstrating the specificity of the radiotracer.
Musachio
J L
JL
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA. jlmusachio@petscan.nm.jhu.edu
Villemagne
V L
VL
Scheffel
U A
UA
Dannals
R F
RF
Dogan
A S
AS
Yokoi
F
F
Wong
D F
DF
D000818:Animals; D001384:Azetidines / Q000138:chemical synthesis*; D001921:Brain / Q000000981:diagnostic imaging; D007457:Iodine Radioisotopes; D008297:Male; D015394:Molecular Structure; D010215:Papio; D011854:Radiochemistry; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000032:analysis*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
C104288:A 85380; D001384:Azetidines; D007457:Iodine Radioisotopes; D011978:Receptors, Nicotinic