Synthesis and Pharmacological Characterization of Conformationally Restricted Retigabine Analogues as Novel Neuronal Kv7 Channel Activators

J Med Chem. 2020 Jan 9;63(1):163-185. doi: 10.1021/acs.jmedchem.9b00796. Epub 2019 Dec 24.

Abstract

Kv7 K+ channels represent attractive pharmacological targets for the treatment of different neurological disorders, including epilepsy. In this paper, 42 conformationally restricted analogues of the prototypical Kv7 activator retigabine have been synthesized and tested by electrophysiological patch-clamp experiments as Kv7 agonists. When compared to retigabine (0.93 ± 0.43 μM), the EC50s for Kv7.2 current enhancements by compound 23a (0.08 ± 0.04 μM) were lower, whereas no change in potency was observed for 24a (0.63 ± 0.07 μM). In addition, compared to retigabine, 23a and 24a showed also higher potency in activating heteromeric Kv7.2/Kv7.3 and homomeric Kv7.4 channels. Molecular modeling studies provided new insights into the chemical features required for optimal interaction at the binding site. Stability studies evidenced improved chemical stability of 23a and 24a in comparison with retigabine. Overall, the present results highlight that the N5-alkylamidoindole moiety provides a suitable pharmacophoric scaffold for the design of chemically stable, highly potent and selective Kv7 agonists.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Carbamates / chemistry
  • Cricetulus
  • Indoles / chemical synthesis
  • Indoles / metabolism
  • Indoles / pharmacology*
  • KCNQ2 Potassium Channel / agonists*
  • KCNQ2 Potassium Channel / genetics
  • KCNQ2 Potassium Channel / metabolism
  • KCNQ3 Potassium Channel / agonists*
  • KCNQ3 Potassium Channel / metabolism
  • Microsomes, Liver / metabolism
  • Models, Molecular
  • Molecular Conformation
  • Mutation
  • Phenylenediamines / chemistry
  • Protein Binding
  • Small Molecule Libraries / chemical synthesis
  • Small Molecule Libraries / metabolism
  • Small Molecule Libraries / pharmacology
  • Structure-Activity Relationship
  • Xenopus laevis

Substances

  • Carbamates
  • Indoles
  • KCNQ2 Potassium Channel
  • KCNQ3 Potassium Channel
  • Phenylenediamines
  • Small Molecule Libraries
  • ezogabine