Indolizidine (−)-235B′ and related structural analogs: Discovery of nicotinic receptor antagonists that inhibit nicotine-evoked [3H]dopamine release
作者:Marharyta Pivavarchyk、Andrew M. Smith、Zhenfa Zhang、Dejun Zhou、Xu Wang、Naoki Toyooka、Hiroshi Tsuneki、Toshiyasu Sasaoka、J. Michael McIntosh、Peter A. Crooks、Linda P. Dwoskin
DOI:10.1016/j.ejphar.2011.02.018
日期:2011.5
Although several therapeutic agents are available to aid in tobacco smoking cessation, relapse rates continue to be high, warranting the development of alternative pharmacotherapies. Nicotine-evoked dopamine release from its presynaptic terminals in the central nervous system leads to reward which maintains continued tobacco use. The ability of indolizidine (-)-235B' and a sub-library of structurally related analogs to inhibit nicotine-evoked [H-3]dopamine release from rat striatal slices was determined in the current study. lndolizidine (-)-235B' inhibited nicotine-evoked [H-3]dopamine release in a concentration-dependent manner (IC50 = 42 nM, I-max = 55%). Compound (-)-237D, the double bond-reduced analog, afforded the greatest inhibitory potency (IC50 = 0.18 nM, I-max = 76%). and was 233-fold more potent than indolizidine (-)-235B'. The des-8-methyl aza-analog of indolizidine (-)-235B', ZZ-272, also inhibited nicotine-evoked [3H]dopamine release (IC50 = 413 nM, I-max = 59%). Concomitant exposure to maximally effective concentrations of indolizidine (-)-235B', ZZ-272 or (-)-237D with a maximally effective concentration of alpha-conotoxin MII, a selective antagonist for alpha 6 beta 2-containing nicotinic receptors, resulted in inhibition of nicotine-evoked [3H]dopamine release no greater than that produced by each compound alone. The latter results suggest that indolizidine (-)-235B', (-)-237D, ZZ-272 and alpha-conotoxin MII inhibit the same alpha-conotoxin MII-sensitive nicotinic receptor subtypes. Thus, indolizidine (-)-235B' and its analogs act as antagonists of alpha 6 beta 2-nicotinic receptors and constitute a novel structural scaffold for the discovery of pharmacotherapies for smoking cessation. (C) 2011 Elsevier B.V. All rights reserved.