Synthesis of an I-123 analog of A-85380 and preliminary SPECT imaging of nicotinic receptors in baboon

Nucl Med Biol. 1999 Feb;26(2):201-7. doi: 10.1016/s0969-8051(98)00101-2.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Azetidines / chemical synthesis*
  • Brain / diagnostic imaging
  • Iodine Radioisotopes
  • Male
  • Molecular Structure
  • Papio
  • Radiochemistry
  • Radioligand Assay
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Nicotinic / analysis*
  • Tomography, Emission-Computed, Single-Photon / methods*


  • A 85380
  • Azetidines
  • Iodine Radioisotopes
  • Receptors, Nicotinic