New Rigid Nicotine Analogues, Carrying a Norbornane Moiety, Are Potent Agonists of α7 and α3* Nicotinic Receptors

J Med Chem. 2019 Feb 28;62(4):1887-1901. doi: 10.1021/acs.jmedchem.8b01372. Epub 2019 Feb 8.

Abstract

A three-dimensional database search has been applied to design a series of endo- and exo-3-(pyridin-3-yl)bicyclo[2.2.1]heptan-2-amines as nicotinic receptor ligands. The synthesized compounds were tested in radioligand binding assay on rat cortex against [3H]-cytisine and [3H]-methyllycaconitine to measure their affinity for α4β2* and α7* nicotinic receptors. The new derivatives showed some preference for the α4β2* over the α7* subtype, with their affinity being dependent on the endo/exo isomerism and on the methylation degree of the basic nitrogen. The endo primary amines displayed the lowest Ki values on both receptor subtypes. Selected compounds (1a, 2a, 3a, and 6a) were tested on heterologously expressed α4β2, α7, and α3β2 receptors and on SHSY-5Y cells. Compounds 1a and 2a showed α4β2 antagonistic properties while behaved as full agonists on recombinant α7 and on SHSY5Y cells. On the α3β2 subtype, only the chloro derivative 2a showed full agonist activity and submicromolar potency (EC50 = 0.43 μM). The primary amines described here represent new chemotypes for the α7 and α3* receptor subtypes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amines / chemical synthesis
  • Amines / pharmacology
  • Animals
  • Cell Line, Tumor
  • Cerebral Cortex / metabolism
  • Drug Design
  • Humans
  • Molecular Docking Simulation
  • Nicotinic Agonists / chemical synthesis
  • Nicotinic Agonists / pharmacology*
  • Nicotinic Antagonists / chemical synthesis
  • Nicotinic Antagonists / pharmacology
  • Norbornanes / chemical synthesis
  • Norbornanes / pharmacology*
  • Pyridines / chemical synthesis
  • Pyridines / pharmacology*
  • Rats
  • Receptors, Nicotinic / metabolism*
  • alpha7 Nicotinic Acetylcholine Receptor / metabolism*

Substances

  • Amines
  • Nicotinic Agonists
  • Nicotinic Antagonists
  • Norbornanes
  • Pyridines
  • Receptors, Nicotinic
  • alpha7 Nicotinic Acetylcholine Receptor
  • nicotinic receptor alpha3beta2
  • nicotinic receptor alpha4beta2