Biotransformation of a Novel Positive Allosteric Modulator of Metabotropic Glutamate Receptor Subtype 5 Contributes to Seizure-Like Adverse Events in Rats Involving a Receptor Agonism-Dependent Mechanism

被引：40

作者：

Bridges, Thomas M. ^{[1
]}

Rook, Jerri M. ^{[1
]}

Noetzel, Meredith J. ^{[1
]}

Morrison, Ryan D. ^{[1
]}

Zhou, Ya ^{[1
]}

Gogliotti, Rocco D. ^{[1
]}

Vinson, Paige N. ^{[1
]}

Xiang, Zixiu ^{[1
]}

Jones, Carrie K. ^{[1
]}

Niswender, Colleen M. ^{[1
]}

Lindsley, Craig W. ^{[1
,2
]}

Stauffer, Shaun R. ^{[1
]}

Conn, P. Jeffrey ^{[1
]}

Daniels, J. Scott ^{[1
]}

机构：

[1] Vanderbilt Univ, Med Ctr, Dept Pharmacol, Vanderbilt Ctr Neurosci Drug Discovery, Nashville, TN 37232 USA

[2] Vanderbilt Univ, Med Ctr, Dept Chem, Vanderbilt Ctr Neurosci Drug Discovery, Nashville, TN 37232 USA

来源：

DRUG METABOLISM AND DISPOSITION | 2013年 / 41卷 / 09期

基金：

美国国家卫生研究院;

关键词：

IN-VIVO; MOLECULAR SWITCHES; LIMBIC SEIZURES; DISCOVERY; MODES; INDUCTION; LIGANDS; BINDING; BRAIN; VITRO;

D O I：

10.1124/dmd.113.052084

中图分类号：

R9 [药学];

学科分类号：

1007 ;

摘要：

Activation of metabotropic glutamate receptor subtype 5 (mGlu(5)) represents a novel strategy for therapeutic intervention into multiple central nervous system disorders, including schizophrenia. Recently, a number of positive allosteric modulators (PAMs) of mGlu(5) were discovered to exhibit in vivo efficacy in rodent models of psychosis, including PAMs possessing varying degrees of agonist activity (ago-PAMs), as well as PAMs devoid of agonist activity. However, previous studies revealed that ago-PAMs can induce seizure activity and behavioral convulsions, whereas pure mGlu(5) PAMs do not induce these adverse effects. We recently identified a potent and selective mGlu(5) PAM, VU0403602, that was efficacious in reversing amphetamine-induced hyperlocomotion in rats. The compound also induced time-dependent seizure activity that was blocked by coadministration of the mGlu(5) antagonist, 2-methyl-6-(phenylethynyl) pyridine. Consistent with potential adverse effects induced by ago-PAMs, we found that VU0403602 had significant allosteric agonist activity. Interestingly, inhibition of VU0403602 metabolism in vivo by a pan cytochrome P450 (P450) inactivator completely protected rats from induction of seizures. P450-mediated biotransformation of VU0403602 was discovered to produce another potent ago-PAM metabolite-ligand (M1) of mGlu(5). Electrophysiological studies in rat hippocampal slices confirmed agonist activity of both M1 and VU0403602 and revealed that M1 can induce epileptiform activity in a manner consistent with its proconvulsant behavioral effects. Furthermore, unbound brain exposure of M1 was similar to that of the parent compound, VU0403602. These findings indicate that biotransformation of mGlu(5) PAMs to active metabolite-ligands may contribute to the epileptogenesis observed after in vivo administration of this class of allosteric receptor modulators.

引用

页码：1703 / 1714

页数：12

共 29 条

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