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5‐HT 1A receptors increase excitability of spinal motoneurons by inhibiting a TASK‐1‐like K + current in the adult turtle
Author(s) -
Perrier JeanFrançois,
Alaburda Aidas,
Hounsgaard Jørn
Publication year - 2003
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2003.00485.x
Subject(s) - turtle (robot) , neuroscience , current (fluid) , receptor , task (project management) , biology , chemistry , medicine , physics , ecology , management , economics , thermodynamics
The modulatory effects of serotonin mediated by 5‐HT 1A receptors in adult spinal motoneurons were investigated by intracellular recordings in a slice preparation from the turtle. In current‐clamp mode, activation of 5‐HT 1A receptors by 8‐OH‐DPAT led to depolarization and an increase in input resistance in most motoneurons but caused hyperpolarization and a decrease in input resistance in the remaining smaller fraction of cells. When slices were preincubated in medium containing the 5‐HT 1A receptor antagonist WAY‐100635, 8‐OH‐DPAT had no effect. In voltage‐clamp mode, with 1 m m CsCl in the bathing medium, 8‐OH‐DPAT consistently inhibited a leak current that was sensitive to extracellular acidification and anandamide, a TASK‐1 channel blocker. In medium with a low pH, as in the presence of anandamide, 8‐OH‐DPAT had no effect. Our results show that activation of 5‐HT 1A receptors contributes to the excitatory effect of serotonin on spinal motoneurons by inhibition of a TASK‐1 potassium channel leading to depolarization and increased input resistance.