Three-dimensional comparison of peripheral benzodiazepine binding and histological findings in rat brain tumor.

Abstract

Experiments were undertaken to determine the in vivo utility of the mixed benzodiazepine ligand [3H]flunitrazepam and the selective peripheral benzodiazepine ligand [3H]PK 11195 [1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide] to outline the borders of rat C6 glial tumors in three dimensions. Intravenous injection of [3H]flunitrazepam resulted in a tumor/cortex ratio of radioactive densities between 2.7 and 1.5 within the first 60 minutes after injection. [3H]PK 11195 demonstrated a higher tumor/cortex ratio (5.3) than [3H]flunitrazepam. For three-dimensional studies, images were generated from thionin-stained histological sections and autoradiograms. The mixed type benzodiazepine ligand [3H]flunitrazepam was superior in showing some of the normal anatomical structures surrounding the tumor, whereas [3H]PK 11195, a specific peripheral ligand, demonstrated higher tumor/brain contrast and superior topographical correlation between histological and autoradiographic images. Implications of peripheral benzodiazepine receptor ligands for positron emission tomography are discussed.

• Authors: K Ikezaki, K L Black, E M Santori, M L Smith, D P Becker, B A Payne, A W Toga
• Journal: Neurosurgery (Neurosurgery) Vol. 27 Issue 1 Pg. 78-82 (Jul 1990) ISSN: 0148-396X [Print] United States
• PMID: 2165576 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Isoquinolines
• Receptors, GABA-A
• Flunitrazepam
• PK 11195

Topics

• Animals
• Brain Neoplasms (diagnostic imaging, metabolism)
• Female
• Flunitrazepam (metabolism)
• Glioma (diagnostic imaging, metabolism)
• Isoquinolines (metabolism)
• Rats
• Rats, Inbred Strains
• Receptors, GABA-A (metabolism)
• Tomography, Emission-Computed (methods)