Referenced in: none

Automatically associated channels: SK1 , SK2 , SK3

Title: 5-HT1A receptors modulate small-conductance Ca2+-activated K+ channels.

Authors: Morten Grunnet, Thomas Jespersen, Jean-François Perrier

Journal, date & volume: J. Neurosci. Res., 2004 Dec 15 , 78, 845-54

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15521063

Abstract
Small-conductance calcium-activated potassium channels (SK) are responsible for the medium afterhyperpolarisation (mAHP) following action potentials in neurons. Here we tested the ability of serotonin (5-HT) to modulate the activity of SK channels by coexpressing 5-HT1A receptors with different subtypes of SK channels (SK1, SK2, and SK3) in Xenopus laevis oocytes. SK channels were activated by intracellular injection of Cd2+. Subsequent activation of 5-HT1A receptors by 8-OH-DPAT always produced an inhibition of the SK current, showing the existence of a specific pathway between the receptor and the ion channel. To investigate the physiological relevance of this pathway, we characterized the mAHP present after action potentials in spinal motoneurons recorded in a slice preparation from the lumbar spinal cord of the adult turtle. By performing current and voltage clamp recordings, we showed that 8-OH-DPAT specifically inhibited the fraction of the AHP mediated by SK channels. We conclude that the activity of SK channels is modulated by activation of serotonergic receptors.