Identification and pharmacological profile of a new class of selective nicotinic acetylcholine receptor potentiators.
Here we report the discovery, by high-throughput screening, of three novel (2-amino-5-keto)thiazole compounds that act as selective potentiators of nicotinic acetylcholine receptors. Compound selectivity was assessed at seven human nicotinic acetylcholine receptors (alpha1beta1gammadelta, alpha2beta4, alpha3beta2, alpha3beta4, alpha4beta2, alpha4beta4, and alpha7) expressed in mammalian cells or Xenopus oocytes. At alpha2beta4, alpha4beta2, alpha4beta4, and alpha7, but not alpha1beta1gammadelta, alpha3beta2, or alpha3beta4, submaximal responses to nicotinic agonists were potentiated in a concentration-dependent manner by all compounds. At similar concentrations, no potentiation of 5-hydroxytryptamine, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, GABA(A), and N-methyl-d-aspartate receptors or voltage-gated Na(+) and Ca(2+) channels was observed. Furthermore, these compounds did not inhibit acetylcholine esterase. Further profiling revealed that these compounds enhanced the potency and maximal efficacy of a range of nicotinic agonists at alpha4beta2 nicotinic acetylcholine receptors, a profile typical of allosteric potentiators. At concentrations required for potentiation, the compounds did not displace [(3)H]epibatidine from the agonist-binding site, and potentiation was observed at all agonist concentrations, suggesting a noncompetitive mechanism of action. Blockade of common second messenger systems did not affect potentiation. At concentrations higher then required for potentiation the compounds also displayed intrinsic agonist activity, which was blocked by competitive and noncompetitive nicotinic acetylcholine receptor (nAChR) antagonists. These novel selective nicotinic receptor potentiators should help in clarifying the potential therapeutic utility of selective nAChR modulation for the treatment of central nervous system disorders.
Broad
Lisa M
LM
Eli Lilly and Company Ltd., Lilly Research Centre, Windlesham, Surrey GU20 6PH, UK.
Zwart
Ruud
R
Pearson
Kathy H
KH
Lee
Martin
M
Wallace
Louise
L
McPhie
Gordon I
GI
Emkey
Renee
R
Hollinshead
Sean P
SP
Dell
Colin P
CP
Baker
S Richard
SR
Sher
Emanuele
E
D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002460:Cell Line; D004357:Drug Synergism; D005702:Galantamine / Q000494:pharmacology; D006801:Humans; D018722:Nicotinic Agonists / Q000494:pharmacology*; D021122:Protein Subunits; D011725:Pyridines / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000187:drug effects*; D011994:Recombinant Proteins / Q000187:drug effects; D014982:Xenopus laevis
D019086:Bridged Bicyclo Compounds, Heterocyclic; D018722:Nicotinic Agonists; D021122:Protein Subunits; D011725:Pyridines; D011978:Receptors, Nicotinic; D011994:Recombinant Proteins; D005702:Galantamine; C082748:epibatidine