(Development of gamma-emitting, receptor-binding radiotracers for imaging the brain and pancreas): Progress report, March 1, 1987-February 28, 1988
3-Quinuclidinyl atrolactate (QNA) is an analogue of 3-quinuclidinyl benzilate (QNB) which exhibits a 25-fold higher affinity for the muscarinic acetylcholine receptor (m-AChR) from the corpus striatum than for the m-AChR from ventricular muscle. A radioiodinated derivative of QNA can be used to bind high affinity m-AChR selectively in the CNS. A simple method was developed to radioiodinate QNB which has been applied to QNA, using a milligram amount of QNA as substrate. Two reaction steps were involved: QNA was reacted with thallic trifluoroacetate at 60/sup 0/C for 24 hours in trifluoroacetic acid, then radioactive I-125/NaI and aluminum chloride were added to the reaction mixture and the reaction was allowed to continue at 70/sup 0/C for another 24 hours. The above reactions were carried out in a sealed ampule. High performance liquid chromatography was employed for the separation of reaction products. The mole ratio of QNA:aluminum chloride:thallic trifluoroacetate was 1:1:1. the radiochemical yield of (3-I-125)QNA was 8%. The specific activity was 35 Ci/mmole and the equilibrium association constant was 2.36 x 10/sup 7/ M/sup -1/. This low affinity indicates a stearic interaction in the 3-position of the phenyl ring of QNA. 1 fig.
- Research Organization:
- George Washington Univ., Washington, DC (USA)
- DOE Contract Number:
- AS05-82ER60039
- OSTI ID:
- 5933191
- Report Number(s):
- DOE/ER/60039-T3; ON: DE88002552
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ACETYLCHOLINE
AMINES
AMMONIUM COMPOUNDS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
CEREBRUM
CHEMICAL PREPARATION
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISTRIBUTION
DOCUMENT TYPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
ESTERS
FLUORINE 18
FLUORINE ISOTOPES
GLANDS
HALOGENATION
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINATION
IODINE 125
IODINE ISOTOPES
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LABELLING
LIGHT NUCLEI
MEMBRANE PROTEINS
NERVOUS SYSTEM
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PANCREAS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
PARTITION
PROGRESS REPORT
PROTEINS
QUATERNARY COMPOUNDS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
STRUCTURE-ACTIVITY RELATIONSHIPS
SYNTHESIS
TISSUE DISTRIBUTION
TRITIUM COMPOUNDS