In vivo kinetics of (H-3)spiperone in rat brain

Conference · Sun Jan 01 04:00:00 EST 1984 · J. Nucl. Med.; (United States)

OSTI ID:7087245

Chugani, D C; Barrio, J R; Huang, S C; Phelps, M E

The quantitative measurement of neuroreceptors with PET and high affinity ligands requires an understanding of those critical variables determining in vivo ligand deposition. The authors have performed kinetic studies of various rat brain regions following bolus intravenous administration of (H-3)spiperone ((H-3)SP; 250 ..mu..Ci/kg, 20 ..mu..g/kg) in order to understand differences they have found between in vivo and in vitro autoradiographic labeling of rat brain sections. Arterial blood samples were collected, and 50 lambda aliquots of plasma were counted. The rats were sacrificed at various times after injection, and the brains were rapidly removed. Striatum, frontal cortex, hippocampus and cerebellum were dissected, homogenized in 10 volumes ethanol and counted. Plasma and brain tritium content were corrected for metabolism to reflect only (H-3)SP. Kinetic curves for brain regions were fitted to a 3-compartment model: plasma ligand in equilibrium free and nonspecifically bound ligand in brain in equilibrium specifically bound ligand in brain. These curves show that (H-3)SP continues to accumulate in striatum up to 3 hr after injection, whereas, its concentration declines after 30 min in frontal cortex. Spiperone binds primarily to dopaminergic receptors in striatum and to serotonergic receptors in frontal cortex with similar affinity for both receptor types. Although the receptor concentration in frontal cortex is approximately half of that in striatum, the cortical receptors are restricted for the most part to lamina IV resulting in local receptor concentrations similar to those in striatum. These results suggest that the authors must look for variables other than receptor number and affinity to explain the differences between (H-3)SP kinetics in striatum and in frontal cortex.

• Research Organization: UCLA School of Medicine, Los Angeles, CA
• OSTI ID: 7087245
• Report Number(s): CONF-840619-
• Conference Information: Journal Name: J. Nucl. Med.; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
AFFINITY
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD PLASMA
BODY
BODY FLUIDS
BRAIN
CARDIOTONICS
CARDIOVASCULAR AGENTS
CENTRAL NERVOUS SYSTEM
CEREBELLUM
CEREBRAL CORTEX
CEREBRUM
COMPUTERIZED TOMOGRAPHY
DIAGNOSTIC TECHNIQUES
DIAGNOSTIC USES
DOPAMINE
DRUGS
EMISSION COMPUTED TOMOGRAPHY
HYDROGEN ISOTOPES
HYDROXY COMPOUNDS
IN VIVO
INJECTION
INTAKE
INTRAVENOUS INJECTION
ISOTOPES
LIGANDS
LIGHT NUCLEI
MAMMALS
MATERIALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHENOLS
POLYPHENOLS
POSITRON COMPUTED TOMOGRAPHY
PROTEINS
RADIOISOTOPES
RADIONUCLIDE KINETICS
RATS
RECEPTORS
RODENTS
SYMPATHOMIMETICS
TOMOGRAPHY
TRITIUM
USES
VERTEBRATES
YEARS LIVING RADIOISOTOPES