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ERG voltage‐gated K + channels regulate excitability and discharge dynamics of the medial vestibular nucleus neurones
Author(s) -
Pessia Mauro,
Servettini Ilenio,
Panichi Roberto,
Guasti Leonardo,
Grassi Silvarosa,
Arcangeli Annarosa,
Wanke Enzo,
Pettorossi Vito Enrico
Publication year - 2008
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 - 10.1113/jphysiol.2008.155762
Subject(s) - erg , medial vestibular nucleus , biophysics , electrophysiology , nucleus , vestibular nuclei , patch clamp , chemistry , physics , neuroscience , anatomy , vestibular system , biology , retina
The discharge properties of the medial vestibular nucleus neurones (MVNn) critically depend on the activity of several ion channel types. In this study we show, immunohistochemically, that the voltage‐gated K + channels ERG1A, ERG1B, ERG2 and ERG3 are highly expressed within the vestibular nuclei of P10 and P60 mice. The role played by these channels in the spike‐generating mechanisms of the MVNn and in temporal information processing was investigated electrophysiologically from mouse brain slices, in vitro , by analysing the spontaneous discharge and the response to square‐, ramp‐ and sinusoid‐like intracellular DC current injections in extracellular and whole‐cell patch‐clamp studies. We show that more than half of the recorded MVNn were responsive to ERG channel block (WAY‐123,398, E4031), displaying an increase in spontaneous activity and discharge irregularity. The response to step and ramp current injection was also modified by ERG block showing a reduction of first spike latency, enhancement of discharge rate and reduction of the slow spike‐frequency adaptation process. ERG channels influence the interspike slope without affecting the spike shape. Moreover, in response to sinusoid‐like current, ERG channel block caused frequency‐dependent gain enhancement and phase‐lead shift. Taken together, the data demonstrate that ERG channels control the excitability of MVNn, their discharge regularity and probably their resonance properties.