PT  - JOURNAL ARTICLE
AU  - Brandon J. Henderson
AU  - Ryan E. Pavlovicz
AU  - Jerad D. Allen
AU  - Tatiana F. González-Cestari
AU  - Crina M. Orac
AU  - Andrew B. Bonnell
AU  - Michael X. Zhu
AU  - R. Thomas Boyd
AU  - Chenglong Li
AU  - Stephen C. Bergmeier
AU  - Dennis B. McKay
TI  - Negative Allosteric Modulators That Target Human α4β2 Neuronal Nicotinic Receptors
AID  - 10.1124/jpet.110.168211
DP  - 2010 Sep 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 761--774
VI  - 334
IP  - 3
4099  - http://jpet.aspetjournals.org/content/334/3/761.short
4100  - http://jpet.aspetjournals.org/content/334/3/761.full
SO  - J Pharmacol Exp Ther2010 Sep 01; 334
AB  - Allosteric modulation of neuronal nicotinic acetylcholine receptors (nAChRs) is considered to be one of the most promising approaches for therapeutics. We have previously reported on the pharmacological activity of several compounds that act as negative allosteric modulators (NAMs) of nAChRs. In the following studies, the effects of 30 NAMs from our small chemical library on both human α4β2 (Hα4β2) and human α3β4 (Hα3β4) nAChRs expressed in human embryonic kidney ts201 cells were investigated. During calcium accumulation assays, these NAMs inhibited nAChR activation with IC50 values ranging from 2.4 μM to more than 100 μM. Several NAMs showed relative selectivity for Hα4β2 nAChRs with IC50 values in the low micromolar range. A lead molecule, KAB-18, was identified that shows relative selectivity for Hα4β2 nAChRs. This molecule contains three phenyl rings, one piperidine ring, and one ester bond linkage. Structure–activity relationship (SAR) analyses of our data revealed three regions of KAB-18 that contribute to its relative selectivity. Predictive three-dimensional quantitative SAR (comparative molecular field analysis and comparative molecular similarity indices analysis) models were generated from these data, and a pharmacophore model was constructed to determine the chemical features that are important for biological activity. Using docking approaches and molecular dynamics on a Hα4β2 nAChR homology model, a binding mode for KAB-18 at the α/β subunit interface that corresponds to the predicted pharmacophore is described. This binding mode was supported by mutagenesis studies. In summary, these studies highlight the importance of SAR, computational, and molecular biology approaches for the design and synthesis of potent and selective antagonists targeting specific nAChR subtypes.