In vivo (/sup 3/H)flunitrazepam binding: imaging of receptor regulation
The use of (/sup 3/H)flunitrazepam as a ligand to measure alterations in benzodiazepine receptors in vivo in rats was investigated. Animals were injected with (/sup 3/H)flunitrazepam i.v., arterial samples of (/sup 3/H)flunitrazepam were obtained and, later, the animals were sacrificed to assay brain binding. (/sup 3/H)flunitrazepam enters the brain rapidly and binds to benzodiazepine receptors. About two-thirds of this binding is blocked by predosing the animals with 5 mg/kg of clonazepam. The amount of remaining (nonspecific) binding correlates very well (r = 0.88) with the amount of radioactivity found in plasma at the time of death. A series of rats were lesioned unilaterally with kainic acid in the caudate-putamen several months before the infusion of (/sup 3/H)flunitrazepam. In vivo autoradiography in lesioned rats showed that benzodiazepine binding in globus pallidus and substantia nigra on the side of the lesion was increased significantly as compared to the intact side. The observed changes in benzodiazepine binding were similar to those observed previously in lesioned rats using in vitro techniques. Thus, benzodiazepine receptor regulation can be imaged quantitatively using in vivo binding techniques.
- Research Organization:
- Univ. of Michigan, Ann Arbor
- OSTI ID:
- 5098009
- Journal Information:
- J. Pharmacol. Exp. Ther.; (United States), Vol. 2
- Country of Publication:
- United States
- Language:
- English
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TRANQUILIZERS
RADIORECEPTOR ASSAY
AUTORADIOGRAPHY
BRAIN
LIGANDS
RATS
RECEPTORS
TRITIUM COMPOUNDS
ANIMALS
BODY
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM AGENTS
DRUGS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
PROTEINS
PSYCHOTROPIC DRUGS
RODENTS
TRACER TECHNIQUES
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550201* - Biochemistry- Tracer Techniques