Clotrimazole and efaroxan inhibit red cell Gardos channel independently of imidazoline I1 and I2 binding sites

Eur J Pharmacol. 1996 Jan 4;295(1):109-12. doi: 10.1016/0014-2999(95)00642-7.


In the present report, we investigated the potential involvement of imidazoline I1 and I2 binding sites in the inhibition of the Ca(2+)-activated K+ channel (Gardos channel) by clotrimazole in human red cells. Ca(2+)-activated 86Rb influx was inhibited by clotrimazole and efaroxan but not by the imidazoline binding site ligands clonidine, moxonidine, cirazoline and idazoxan (100 microM). Binding studies with [3H]idazoxan and [3H]p-aminoclonidine did not reveal the expression of I1 and I2 binding sites in erythrocytes. These data indicate that the effects of clotrimazole and efaroxan on the erythrocyte Ca(2+)-activated K+ channel may be mediated by a 'non-I1/non-I2' binding site.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic alpha-Antagonists / pharmacology*
  • Benzofurans / pharmacology*
  • Binding Sites
  • Calcium / pharmacology
  • Clotrimazole / pharmacology*
  • Dose-Response Relationship, Drug
  • Erythrocytes / drug effects
  • Erythrocytes / metabolism*
  • Humans
  • Imidazoles / metabolism*
  • Imidazoles / pharmacology*
  • Potassium Channels / drug effects*


  • Adrenergic alpha-Antagonists
  • Benzofurans
  • Imidazoles
  • Potassium Channels
  • efaroxan
  • Clotrimazole
  • Calcium