Preparation and biodistribution of [125I]IBZM: a potential CNS D-2 dopamine receptor imaging agent

Int J Rad Appl Instrum B. 1988;15(2):195-201. doi: 10.1016/0883-2897(88)90088-8.

Abstract

A new CNS D-2 dopamine receptor imaging agent [125I]IBZM, (S)-3-[125I]-iodo-N-[(1-ethyl-2-pyrrolidinyl)] methyl-2-hydroxy-6-methoxybenzamide, was prepared by either an exchange reaction or by the chloramine-T method. After an i.v. injection, the agent easily passed through the blood-brain barrier and localized in the rat brain. At 2, 15, 30 and 60 min after the injection, the brain uptake was 2.9, 2.3, 1.8 and 0.7% dose/organ, respectively. Regional uptake ratio of striatum/cerebellum (target to nontarget ratio) increased from 1.4 at 30 s to 10.3 at 2 h after the i.v. injection. Digital autoradiography of rat brain sections showed high regional uptake in the caudate putamen and accumbens nucleus, areas known to have a high concentration of the D-2 dopamine receptor. The specific uptake at the D-2 dopamine receptor site was blocked by pretreatment with spiperone, a selective D-2 antagonist. When labeled with 123I (t1/2 = 13 h, 159 keV), [123I]IBZM may be useful for imaging the CNS D-2 dopamine receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Benzamides / pharmacokinetics*
  • Brain / diagnostic imaging*
  • Iodine Radioisotopes*
  • Isotope Labeling / methods
  • Male
  • Pyrrolidines / pharmacokinetics*
  • Rats
  • Receptors, Dopamine / diagnostic imaging*
  • Receptors, Dopamine D2
  • Tissue Distribution
  • Tomography, Emission-Computed

Substances

  • Benzamides
  • Iodine Radioisotopes
  • Pyrrolidines
  • Receptors, Dopamine
  • Receptors, Dopamine D2
  • 3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide