Abstract
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).
| Original language | English |
|---|---|
| Journal | Neuropharmacology |
| Volume | 40 |
| Issue number | 7 |
| Pages (from-to) | 879-887 |
| Number of pages | 9 |
| ISSN | 0028-3908 |
| Publication status | Published - 1 Jun 2001 |
Keywords
- 4-Aminopyridine
- Amitriptyline
- Animals
- Antidepressive Agents, Tricyclic
- Apamin
- Bicuculline
- Cell Line
- Humans
- Neuroprotective Agents
- Potassium Channels
- Potassium Channels, Calcium-Activated
- Rats
- Riluzole
- Small-Conductance Calcium-Activated Potassium Channels