Pharmacological modulation of SK3 channels

Neuropharmacology. 2001 Jun;40(7):879-87. doi: 10.1016/s0028-3908(01)00028-4.


Small-conductance, calcium-activated K+ channels (SK channels) are voltage-insensitive channels that have been identified molecularly within the last few years. As SK channels play a fundamental role in most excitable cells and participate in afterhyperpolarization (AHP) and spike-frequency adaptation, pharmacological modulation of SK channels may be of significant clinical importance. Here we report the functional expression of SK3 in HEK293 and demonstrate a broad pharmacological profile for these channels. Brain slice studies commonly employ 4-aminopyridine (4-AP) to block voltage-dependent K+ channels or a methyl derivative of bicuculline, a blocker of gamma-aminobutyric acid (GABA)-gated Cl- channels, in order to investigate the role of various synapses in specialized neural networks. However, in this study both 4-AP and bicuculline are shown to inhibit SK3 channels (IC50 values of 512 microM and 6 microM, respectively) at concentrations lower than those used for brain slice recordings. Riluzole, a potent neuroprotective drug with anti-ischemic, anticonvulsant and sedative effects currently used in the treatment of amyotrophic lateral sclerosis, activates SK3 channels at concentrations of 3 microM and above. Amitriptyline, a tricyclic antidepressive widely used clinically, inhibits SK3 channels with an IC50 of 39.1 +/- 10 microM (n=6).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Aminopyridine / pharmacology
  • Amitriptyline / pharmacology*
  • Animals
  • Antidepressive Agents, Tricyclic / pharmacology*
  • Apamin / pharmacology
  • Bicuculline / analogs & derivatives*
  • Bicuculline / pharmacology
  • Cell Line
  • Humans
  • Neuroprotective Agents / pharmacology*
  • Potassium Channels / drug effects*
  • Potassium Channels / metabolism
  • Potassium Channels, Calcium-Activated*
  • Rats
  • Riluzole / pharmacology*
  • Small-Conductance Calcium-Activated Potassium Channels


  • Antidepressive Agents, Tricyclic
  • Kcnn3 protein, rat
  • Neuroprotective Agents
  • Potassium Channels
  • Potassium Channels, Calcium-Activated
  • Small-Conductance Calcium-Activated Potassium Channels
  • Amitriptyline
  • Apamin
  • bicuculline methobromide
  • Riluzole
  • 4-Aminopyridine
  • Bicuculline