QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: mol.108.049551v1 74/5/1345    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Niswender, C. M. Articles by Conn, P. J. Search for Related Content PubMed PubMed Citation Articles by Niswender, C. M. Articles by Conn, P. J.

Discovery, Characterization, and Antiparkinsonian Effect of Novel Positive Allosteric Modulators of Metabotropic Glutamate Receptor 4

Department of Pharmacology (C.M.N., K.A.J., C.D.W., C.K.J., Z.X., Q.L., A.L.R., J.E.M., T.D.P., A.D.T., J.E.A., R.W., C.W.L., P.J.C.), Department of Chemistry (C.W.L.), Vanderbilt Program in Drug Discovery (C.M.N., K.A.J., C.D.W., C.K.J., Z.X., Q.L., A.L.R., J.E.M., A.D.T., R.W., C.W.L., P.J.C.), and Vanderbilt Institute for Chemical Biology (C.D.W., E.L.D., T.N., C.A.A., M.B.W., C.W.L., P.J.C.), Vanderbilt University, Nashville, Tennessee

Parkinson's disease (PD) is caused by the death of dopamine neurons in the basal ganglia and results in motor symptoms such as tremor and bradykinesia. Activation of metabotropic glutamate receptor 4 (mGluR4) has been shown to modulate neurotransmission in the basal ganglia and results in antiparkinsonian effects in rodent PD models. N-Phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxamide (PHCCC) is a positive allosteric modulator (PAM) of mGluR4 that has been used to further validate the role of mGluR4 in PD, but the compound suffers from a lack of selectivity, relatively low potency, and poor solubility. Via high-throughput screening, we discovered more than 400 novel PAMs of mGluR4. Compounds derived from a novel chemical scaffold were characterized in vitro at both rat and human mGluR4 using two distinct assays of mGluR4 function. The lead compound was approximately 8-fold more potent than PHCCC, enhanced the potency of glutamate at mGluR4 by 8-fold, and did not show any significant potentiator or antagonist activity at other mGluR subtypes. Resolution of the regioisomers of the lead revealed that the cis regioisomer, (±)-cis-2-(3,5-dichlorphenylcarbamoyl)cyclohexanecarboxylic acid (VU0155041), contained the majority of the mGluR4 PAM activity and also exhibited partial agonist activity at mGluR4 at a site that was distinct from the glutamate binding site, suggesting that this compound is a mixed allosteric agonist/PAM of mGluR4. VU0155041 was soluble in an aqueous vehicle, and intracerebroventricular administration of 31 to 316 nmol of VU0155041 dose-dependently decreased haloperidol-induced catalepsy and reserpine-induced akinesia in rats. These exciting results provide continued support for mGluR4 as a therapeutic target in PD.

Address correspondence to: Colleen M. Niswender, 1215 MRB IV, Department of Pharmacology, Vanderbilt University, Nashville, TN 37232. E-mail: colleen.niswender{at}vanderbilt.edu

This article has been cited by other articles:

				J. E. Marlo, C. M. Niswender, E. L. Days, T. M. Bridges, Y. Xiang, A. L. Rodriguez, J. K. Shirey, A. E. Brady, T. Nalywajko, Q. Luo, et al. Discovery and Characterization of Novel Allosteric Potentiators of M1 Muscarinic Receptors Reveals Multiple Modes of Activity Mol. Pharmacol., March 1, 2009; 75(3): 577 - 588. [Abstract] [Full Text] [PDF]