Biomaterial Database

A family of highly selective allosteric modulators of the metabotropic glutamate receptor subtype 5. 2003

Julie A O'Brien, and Wei Lemaire, and Tsing-Bau Chen, and Raymond S L Chang, and Marlene A Jacobson, and Sookhee N Ha, and Craig W Lindsley, and Hervé J Schaffhauser, and Cyrille Sur, and Douglas J Pettibone, and P Jeffrey Conn, and David L Williams

Neuroscience-WP46-300, Merck Research Laboratories, West Point, PA 19486, USA.

We have identified a family of highly selective allosteric modulators of the group I metabotropic glutamate receptor subtype 5 (mGluR5). This family of closely related analogs exerts a spectrum of effects, ranging from positive to negative allosteric modulation, and includes compounds that do not themselves modulate mGluR5 agonist activity but rather prevent other family members from exerting their modulatory effects. 3,3'-Difluorobenzaldazine (DFB) has no agonist activity, but it acts as a selective positive allosteric modulator of human and rat mGluR5. DFB potentiates threshold responses to glutamate, quisqualate, and 3,5-dihydroxyphenylglycine in fluorometric Ca2+ assays 3- to 6-fold, with EC50 values in the 2 to 5 microM range, and at 10 to 100 microM, it shifts mGluR5 agonist concentration-response curves approximately 2-fold to the left. The analog 3,3'-dimethoxybenzaldazine (DMeOB) acts as a negative modulator of mGluR5 agonist activity, with an IC50 of 3 microM in fluorometric Ca2+ assays, whereas the analog 3,3'-dichlorobenzaldazine (DCB) does not exert any apparent modulatory effect on mGluR5 activity. However, DCB seems to act as an allosteric ligand with neutral cooperativity, preventing the positive allosteric modulation of mGluRs by DFB as well as the negative modulatory effect of DMeOB. None of these analogs affects binding of [3H]quisqualate to the orthosteric (glutamate) site, but they do inhibit [3H]3-methoxy-5-(2-pyridinylethynyl)pyridine binding to the site for 2-methyl-6-(phenylethynyl)-pyridine, a previously identified negative allosteric modulator. With the use of these compounds, we provide evidence that allosteric sites on GPCRs can respond to closely related ligands with a range of pharmacological activities from positive to negative modulation as well as to neutral competition of this modulation.

UI	MeSH Term	Description	Entries
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000494	Allosteric Regulation	The modification of the reactivity of ENZYMES by the binding of effectors to sites (ALLOSTERIC SITES) on the enzymes other than the substrate BINDING SITES.	Regulation, Allosteric,Allosteric Regulations,Regulations, Allosteric
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D016466	CHO Cells	CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.	CHO Cell,Cell, CHO,Cells, CHO
D018094	Receptors, Metabotropic Glutamate	Cell surface proteins that bind glutamate and act through G-proteins to influence second messenger systems. Several types of metabotropic glutamate receptors have been cloned. They differ in pharmacology, distribution, and mechanisms of action.	Glutamate Receptors, Metabotropic,Metabotropic Glutamate Receptors,Receptors, Glutamate, Metabotropic,Metabotropic Glutamate Receptor,Glutamate Receptor, Metabotropic,Receptor, Metabotropic Glutamate
D018690	Excitatory Amino Acid Agonists	Drugs that bind to and activate excitatory amino acid receptors.	Amino Acids, Excitatory, Agonists,Glutamate Agonists,Agonists, Excitatory Amino Acid,Amino Acid Agonist, Excitatory,Amino Acid Agonists, Excitatory,EAA Agonist,EAA Agonists,Excitatory Amino Acid Agonist,Glutamate Agonist,Agonist, EAA,Agonist, Glutamate,Agonists, EAA,Agonists, Glutamate
D018691	Excitatory Amino Acid Antagonists	Drugs that bind to but do not activate excitatory amino acid receptors, thereby blocking the actions of agonists.	Amino Acids, Excitatory, Antagonists,Excitatory Amino Acid Antagonist,Glutamate Antagonist,Glutamate Antagonists,Glutamate Receptor Antagonist,Amino Acid Antagonists, Excitatory,Antagonists, Excitatory Amino Acid,EAA Antagonists,Glutamate Receptor Antagonists,Antagonist, Glutamate,Antagonist, Glutamate Receptor,Antagonists, EAA,Antagonists, Glutamate,Antagonists, Glutamate Receptor,Receptor Antagonist, Glutamate,Receptor Antagonists, Glutamate