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Kv4 (A‐type) potassium currents in the mouse medial nucleus of the trapezoid body
Author(s) -
Johnston Jamie,
Griffin Sarah J.,
Baker Claire,
Forsythe Ian D.
Publication year - 2008
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2008.06116.x
Subject(s) - cardiac transient outward potassium current , chemistry , nucleus , trapezoid body , biophysics , tetraethylammonium , membrane potential , electrophysiology , neuroscience , potassium channel , potassium , current (fluid) , patch clamp , biology , biochemistry , physics , organic chemistry , thermodynamics
Principal neurones of the mouse medial nucleus of the trapezoid body (MNTB) possess multiple voltage‐gated potassium currents, including a transient outward current (or A‐current), which is characterized here. The A‐current exhibited rapid voltage‐dependent inactivation and was half inactivated at resting membrane potentials. Following a hyperpolarizing pre‐pulse to remove inactivation, the peak transient current was 1.07 nA at −17 mV. The pharmacological characteristics of this A‐current were consistent with Kv4 subunits in expression studies; the A‐current was resistant to block by tetraethylammonium and dendrotoxin‐I but sensitive to millimolar concentrations of 4‐aminopyridine and 5 µ m hanatoxin. Immunohistochemistry confirmed that Kv4.3 sub‐units are present in the MNTB. In a single‐compartment model of an MNTB neurone, the A‐current served to accelerate the decay of the initial action potentials in a stimulus train and suggested that removal of A‐current steady‐state inactivation could raise firing threshold for non‐calyceal synaptic inputs. This A‐type current was not observed in the rat.