Cigarette smoking is the number one health problem accounting for more illness and deaths in the US than any other factor. Elucidating the mechanism of action of nicotine (NIC) is of importance in understanding the initiation and maintenance of tobacco smoking behavior. Over the past 10 years, there has been a substantial increase in the understanding of brain nicotinic receptors at the molecular level. The structural and functional diversity of these receptors has stimulated interest in the development of subtype selective agonists. Surprisingly little attention has focussed on the development of subtype selective antagonists. The proposed research will determine the structure activity relationship (SAR) of a new class of nicotinic antagonists, i.e., pyridine-N substituted NIC analogues. Preliminary results demonstrate that N-octylnicotinium iodide (NONI) is a potent and selective antagonist of NIC evoked [3H]dopamine (DA) release. NONI has been prepared as a [3H]ligand (specific activity, 80 Ci/mmol) for determining the regional localization of the specific nicotinic receptor subtype involved in NIC evoked [3H]DA release. N-decylnicotinium iodide (NDNI), competitively and with high affinity binds to the [3H]NIC binding site, but does not inhibit NIC evoked [3H]DA release. These preliminary data demonstrate that pyridine-N substitution of the NIC molecule confers nicotinic receptor antagonist activity to these analogues, and moreover, suggests that NONI and NDNI are selective for different nicotinic receptor subtypes. The proposed research will test the hypothesis that SAR directed at the pyridine-N substituent will optimize the potency, efficacy, and moreover, nicotinic receptor subtype selectivity of this novel class of nicotinic receptor antagonist. Pyridine-N substituents to be studied include varying steric bulk and lipophilicity, alteration of C-2' chirality, and enlargement of the pyrrolidine ring to a piperidine ring. The rotameric preference about the C(3)-C(2') bond will also be determined by incorporating active antagonist molecules into a conformationally more rigid structure. Thus, the major goal of this proposal is to determine structural features of the novel NIC analogues that convert the NIC molecule from an agonist to an antagonist at specific nicotinic receptor subtypes. These subtype selective nicotinic receptor antagonists would be invaluable neuropharmacological agents for basic and clinical research.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA010934-03
Application #
6137806
Study Section
Human Development Research Subcommittee (NIDA)
Program Officer
Hillery, Paul
Project Start
1998-01-15
Project End
2001-12-31
Budget Start
2000-01-27
Budget End
2000-12-31
Support Year
3
Fiscal Year
2000
Total Cost
$205,874
Indirect Cost
Name
University of Kentucky
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
832127323
City
Lexington
State
KY
Country
United States
Zip Code
40506
Dwoskin, Linda P; Joyce, B Matthew; Zheng, Guangrong et al. (2007) Discovery of a novel nicotinic receptor antagonist for the treatment of nicotine addiction: 1-(3-Picolinium)-12-triethylammonium-dodecane dibromide (TMPD). Biochem Pharmacol 74:1271-82
Wilkins Jr, Lincoln H; Miller, Dennis K; Ayers, Joshua T et al. (2005) N-n-alkylnicotinium analogs, a novel class of antagonists at alpha 4 beta 2* nicotinic acetylcholine receptors: inhibition of S(-)-nicotine-evoked 86Rb+ efflux from rat thalamic synaptosomes. AAPS J 7:E922-30
Dwoskin, Linda P; Sumithran, Sangeetha P; Zhu, Jun et al. (2004) Subtype-selective nicotinic receptor antagonists: potential as tobacco use cessation agents. Bioorg Med Chem Lett 14:1863-7
Allen, David D; Lockman, Paul R; Roder, Karen E et al. (2003) Active transport of high-affinity choline and nicotine analogs into the central nervous system by the blood-brain barrier choline transporter. J Pharmacol Exp Ther 304:1268-74
Grinevich, Vladimir P; Crooks, Peter A; Sumithran, Sangeetha P et al. (2003) N-n-alkylpyridinium analogs, a novel class of nicotinic receptor antagonists: selective inhibition of nicotine-evoked [3H] dopamine overflow from superfused rat striatal slices. J Pharmacol Exp Ther 306:1011-20
Wilkins Jr, Lincoln H; Grinevich, Vladimir P; Ayers, Joshua T et al. (2003) N-n-alkylnicotinium analogs, a novel class of nicotinic receptor antagonists: interaction with alpha4beta2* and alpha7* neuronal nicotinic receptors. J Pharmacol Exp Ther 304:400-10
Chen, Jianhong; Norrholm, Seth; Dwoskin, Linda P et al. (2003) N,N-disubstituted piperazines: synthesis and affinities at alpha4beta2(*) and alpha7(*) neuronal nicotinic acetylcholine receptors. Bioorg Med Chem Lett 13:97-100
Wilkins Jr, Lincoln H; Haubner, Aaron; Ayers, Joshua T et al. (2002) N-n-alkylnicotinium analogs, a novel class of nicotinic receptor antagonist: inhibition of S(-)-nicotine-evoked [(3)H]dopamine overflow from superfused rat striatal slices. J Pharmacol Exp Ther 301:1088-96
Ayers, Joshua T; Dwoskin, Linda P; Deaciuc, A Gabriela et al. (2002) bis-Azaaromatic quaternary ammonium analogues: ligands for alpha4beta2* and alpha7* subtypes of neuronal nicotinic receptors. Bioorg Med Chem Lett 12:3067-71
Dwoskin, L P; Crooks, P A (2001) Competitive neuronal nicotinic receptor antagonists: a new direction for drug discovery. J Pharmacol Exp Ther 298:395-402

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