PET imaging with [11C]PBR28 can localize and quantify upregulated peripheral benzodiazepine receptors associated with cerebral ischemia in rat

Neurosci Lett. 2007 Jan 16;411(3):200-5. doi: 10.1016/j.neulet.2006.09.093. Epub 2006 Nov 28.


Peripheral benzodiazepine receptors (PBRs) are upregulated on activated microglia. We recently developed a promising positron emission tomography (PET) ligand, [11C]PBR28, with high affinity and excellent ratio of specific to nonspecific binding. We assessed the ability of [11C]PBR28 PET to localize PBRs in a rat permanent middle cerebral artery occlusion (MCAO) model of neuroinflammation. [11C]PBR28 was intravenously administered to rats at 4 and 7 days after permanent MCAO. In all experiments, arterial blood was sampled for compartmental modeling of regional distribution volumes, and rat brains were sampled after imaging for in vitro [3H]PK 11195 autoradiography and histological evaluation. [11C]PBR28 PET and [3H]PK 11195 autoradiography showed similar areas of increased PBRs, especially in the peri-ischemic core. Results from these in vivo and in vitro methods were strongly correlated. In this first study to demonstrate neuroinflammation in vivo with small animal PET, [11C]PBR28 had adequate sensitivity to localize and quantify the associated increase in PBRs.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Acetamides / pharmacokinetics*
  • Animals
  • Autoradiography / methods
  • Brain Ischemia / diagnostic imaging*
  • Brain Ischemia / metabolism*
  • Brain Ischemia / pathology
  • Carbon Isotopes / pharmacokinetics
  • Image Processing, Computer-Assisted / methods
  • Isoquinolines / pharmacokinetics
  • Male
  • Phenyl Ethers / pharmacokinetics*
  • Positron-Emission Tomography*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, GABA-A / metabolism*
  • Time Factors
  • Tissue Distribution


  • Acetamides
  • Carbon Isotopes
  • DAA 1106
  • Isoquinolines
  • Phenyl Ethers
  • Receptors, GABA-A
  • PK 11195