Kinetics and displacement of [11C]RO 15-1788, a benzodiazepine antagonist, studied in human brain in vivo by positron tomography

Eur J Pharmacol. 1985 Apr 2;110(2):247-51. doi: 10.1016/0014-2999(85)90218-3.


The brain regional distribution and kinetics of RO 15-1788, a benzodiazepine (BZD) antagonist labeled with 11C was studied by time-of-flight positron tomography after intravenous injection in four normal human volunteers. In two control studies, there was a high uptake of [11C]RO 15-1788 in gray matter structures initially (brain/blood ratio approximately 3), and subsequent retention that was highest in cerebral cortex, a structure known to have a high density of BZD receptors in vitro. Variation in tissue kinetics of [11C]RO among different gray matter structures may, however, suggest regional differences in binding characteristics or environment of BZD receptors. In two displacement studies, unlabeled RO 15-1788 was injected ten minutes after the radioligand: there was an immediate and marked washout of [11C]brain radioactivity that reached 70% in the occipital cortex with a 0.05 mg/kg dose (indicating a high specific to non-specific binding ratio) but was less prominent with a 0.01 mg/kg dose. These data suggest that [11C]RO 15-1788 may be useful for in vivo mapping of human brain BZD receptors using positron tomography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Benzodiazepinones / blood
  • Benzodiazepinones / metabolism*
  • Brain / diagnostic imaging
  • Brain / metabolism*
  • Convulsants / blood
  • Convulsants / metabolism*
  • Female
  • Flumazenil
  • Humans
  • Kinetics
  • Male
  • Middle Aged
  • Receptors, GABA-A / metabolism
  • Tomography, Emission-Computed


  • Benzodiazepinones
  • Convulsants
  • Receptors, GABA-A
  • Flumazenil