Biomaterial Database

Preclinical Evaluation of the First Adenosine A1 Receptor Partial Agonist Radioligand for Positron Emission Tomography Imaging. 2018

Min Guo, and Zhan-Guo Gao, and Ryan Tyler, and Tyler Stodden, and Yang Li, and Joseph Ramsey, and Wen-Jing Zhao, and Gene-Jack Wang, and Corinde E Wiers, and Joanna S Fowler, and Kenner C Rice, and Kenneth A Jacobson, and Sung Won Kim, and Nora D Volkow

Laboratory of Neuroimaging , National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health , Bethesda , Maryland 20892-1013 , United States.

Central adenosine A1 receptor (A1R) is implicated in pain, sleep, substance use disorders, and neurodegenerative diseases, and is an important target for pharmaceutical development. Radiotracers for A1R positron emission tomography (PET) would enable measurement of the dynamic interaction of endogenous adenosine and A1R during the sleep-awake cycle. Although several human A1R PET tracers have been developed, most are xanthine-based antagonists that failed to demonstrate competitive binding against endogenous adenosine. Herein, we explored non-nucleoside (3,5-dicyanopyridine and 5-cyanopyrimidine) templates for developing an agonist A1R PET radiotracer. We synthesized novel analogues, including 2-amino-4-(3-methoxyphenyl)-6-(2-(6-methylpyridin-2-yl)ethyl)pyridine-3,5-dicarbonitrile (MMPD, 22b), a partial A1R agonist of sub-nanomolar affinity. [11C]22b showed suitable blood-brain barrier (BBB) permeability and test-retest reproducibility. Regional brain uptake of [11C]22b was consistent with known brain A1R distribution and was blocked significantly by A1R but not A2AR ligands. [11C]22b is the first BBB-permeable A1R partial agonist PET radiotracer with the promise of detecting endogenous adenosine fluctuations.

UI	MeSH Term	Description	Entries
D008024	Ligands	A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)	Ligand
D001812	Blood-Brain Barrier	Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.	Brain-Blood Barrier,Hemato-Encephalic Barrier,Barrier, Blood-Brain,Barrier, Brain-Blood,Barrier, Hemato-Encephalic,Barriers, Blood-Brain,Barriers, Brain-Blood,Barriers, Hemato-Encephalic,Blood Brain Barrier,Blood-Brain Barriers,Brain Blood Barrier,Brain-Blood Barriers,Hemato Encephalic Barrier,Hemato-Encephalic Barriers
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D043682	Receptor, Adenosine A1	A subtype of ADENOSINE RECEPTOR that is found expressed in a variety of tissues including the BRAIN and DORSAL HORN NEURONS. The receptor is generally considered to be coupled to the GI, INHIBITORY G-PROTEIN which causes down regulation of CYCLIC AMP.	Adenosine A1 Receptors,Adenosine A1 Receptor,Receptors, Adenosine A1
D049268	Positron-Emission Tomography	An imaging technique using compounds labelled with short-lived positron-emitting radionuclides (such as carbon-11, nitrogen-13, oxygen-15 and fluorine-18) to measure cell metabolism. It has been useful in study of soft tissues such as CANCER; CARDIOVASCULAR SYSTEM; and brain. SINGLE-PHOTON EMISSION-COMPUTED TOMOGRAPHY is closely related to positron emission tomography, but uses isotopes with longer half-lives and resolution is lower.	PET Imaging,PET Scan,Positron-Emission Tomography Imaging,Tomography, Positron-Emission,Imaging, PET,Imaging, Positron-Emission Tomography,PET Imagings,PET Scans,Positron Emission Tomography,Positron Emission Tomography Imaging,Positron-Emission Tomography Imagings,Scan, PET,Tomography Imaging, Positron-Emission,Tomography, Positron Emission
D057809	HEK293 Cells	A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.	293T Cells,HEK 293 Cell Line,HEK 293 Cells,Human Embryonic Kidney Cell Line 293,Human Kidney Cell Line 293,293 Cell, HEK,293 Cells, HEK,293T Cell,Cell, 293T,Cell, HEK 293,Cell, HEK293,Cells, 293T,Cells, HEK 293,Cells, HEK293,HEK 293 Cell,HEK293 Cell
D058907	Adenosine A1 Receptor Agonists	Compounds that bind to and stimulate ADENOSINE A1 RECEPTORS.