A novel selective positive allosteric modulator of metabotropic glutamate receptor subtype 5 has in vivo activity and antipsychotic-like effects in rat behavioral models.

Kinney GG, O'Brien JA, Lemaire W, Burno M, Bickel DJ, Clements MK, Chen TB, Wisnoski DD, Lindsley CW, Tiller PR, Smith S, Jacobson MA, Sur C, Duggan ME, Pettibone DJ, Conn PJ, Williams DL
J Pharmacol Exp Ther. 2005 313 (1): 199-206

PMID: 15608073 · DOI:10.1124/jpet.104.079244

We found that 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) is a potent and selective positive allosteric modulator of the metabotropic glutamate receptor subtype 5 (mGluR5). In Chinese hamster ovary cells expressing human mGluR5, CDPPB potentiated threshold responses to glutamate in fluorometric Ca2+ assays more than 7-fold with an EC50 value of approximately 27 nM. At 1 microM, CDPPB shifted mGluR5 agonist concentration response curves to glutamate, quisqualate, and (R,S)-3,5-dihydroxyphenylglycine 3- to 9-fold to the left. At higher concentrations, CDPPB exhibited agonist-like activity on cells expressing mGluR5. No other activity was observed on any other mGluR or cell type at concentrations up to 10 microM. CDPPB had no effect on [3H]quisqualate binding to mGluR5 but did compete for binding of [3H]methoxyPEPy, an analog of the selective mGluR5 negative allosteric modulator MPEP. CDPPB was found to be brain penetrant and reversed amphetamine-induced locomotor activity and amphetamine-induced deficits in prepulse inhibition in rats, two models sensitive to antipsychotic drug treatment. These results demonstrate that positive allosteric modulation of mGluR5 produces behavioral effects, suggesting that such modulation serves as a viable approach to increasing mGluR5 activity in vivo. These effects are consistent with the hypothesis that allosteric potentiation of mGluR5 may provide a novel approach for development of antipsychotic agents.

MeSH Terms (29)

Amino Acids Amphetamine Animals Antipsychotic Agents ATP Binding Cassette Transporter, Subfamily B, Member 1 Behavior, Animal Benzamides Cell Line Central Nervous System Stimulants CHO Cells Cricetinae Dogs Excitatory Amino Acid Antagonists Female Haplorhini Humans Image Interpretation, Computer-Assisted In Vitro Techniques Microsomes, Liver Models, Statistical Motor Activity Phthalimides Radioligand Assay Rats Rats, Sprague-Dawley Receptor, Metabotropic Glutamate 5 Receptors, Metabotropic Glutamate Reflex, Startle Xanthenes

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