Quantitative in vivo receptor binding. I. Theory and application to the muscarinic cholinergic receptor

Journal Article · Fri Feb 01 00:00:00 EST 1985 · J. Neurosci.; (United States)

OSTI ID:5676010

Frey, K A; Ehrenkaufer, R L; Beaucage, S; Agranoff, B W

A novel approach to in vivo receptor binding experiments is presented which allows direct quantitation of binding site densities. The method is based on an equilibrium model of tracer uptake and is designed to produce a static distribution proportional to receptor density and to minimize possible confounding influences of regional blood flow, blood-brain barrier permeability, and nonspecific binding. This technique was applied to the measurement of regional muscarinic cholinergic receptor densities in rat brain using (/sup 3/H)scopolamine. Specific in vivo binding of scopolamine demonstrated saturability, a pharmacologic profile, and regional densities which are consistent with interaction of the tracer with the muscarinic receptor. Estimates of receptor density obtained with the in vivo method and in vitro measurements in homogenates were highly correlated. Furthermore, reduction in striatal muscarinic receptors following ibotenic acid lesions resulted in a significant decrease in tracer uptake in vivo, indicating that the correlation between scopolamine distribution and receptor density may be used to demonstrate pathologic conditions. We propose that the general method presented here is directly applicable to investigation of high affinity binding sites for a variety of radioligands.

• Research Organization: Univ. of Michigan, Ann Arbor
• OSTI ID: 5676010
• Journal Information: J. Neurosci.; (United States), Vol. 5:2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACETYLCHOLINE
RECEPTORS
PARASYMPATHOLYTICS
TISSUE DISTRIBUTION
CEREBRUM
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DISTRIBUTION
DRUGS
ESTERS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
NERVOUS SYSTEM
NEUROREGULATORS
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOMIMETICS
QUATERNARY COMPOUNDS
RODENTS
VERTEBRATES
550801* - Morphology- Tracer Techniques
550501 - Metabolism- Tracer Techniques