title: ERG voltage-gated K+ channels regulate excitability and discharge dynamics of the medial vestibular nucleus neurones.
abstract: 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.
authors: Department of Internal Medicine, Section of Human Physiology, University of Perugia, Perugia, Italy. pessia@unipg.it
authors: Mauro
authors: M
authors: Pessia
authors: Ilenio
authors: I
authors: Servettini
authors: Roberto
authors: R
authors: Panichi
authors: Leonardo
authors: L
authors: Guasti
authors: Silvarosa
authors: S
authors: Grassi
authors: Annarosa
authors: A
authors: Arcangeli
authors: Enzo
authors: E
authors: Wanke
authors: Vito Enrico
authors: VE
authors: Pettorossi
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D051638:Ether-A-Go-Go Potassium Channels / Q000502:physiology*; D015640:Ion Channel Gating / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008959:Models, Neurological; D011188:Potassium / Q000378:metabolism*; D014726:Vestibular Nuclei / Q000502:physiology*
chemical_list: D051638:Ether-A-Go-Go Potassium Channels; D011188:Potassium