Deafness associated changes in expression of two-pore domain potassium channels in the rat cochlear nucleus

Two-pore domain potassium channels (K-2PD(+)) play an important role in setting resting membrane potential by regulating background leakage of potassium ions, which in turn controls neuronal excitability. To determine whether these channels contribute to activitydependent plasticity following deafness, we used quantitative real-time PCR to examine the expression of 10 K-2PD(+), subunits in the rat cochlear nucleus at 3 days, 3 weeks and 3 months after bilateral cochlear ablation. There was a large sustained decrease in the expression of TASK-5, a subunit that is predominantly expressed in auditory brain stem neurons, and in the TASK-1 subunit which is highly expressed in several types of cochlear nucleus neurons. TWIK-1 and THIK-2 also showed significant decreases in expression that were maintained across all time points. TWIK-2, TREK-1 and TREK-2 showed no significant change in expression at 3 days but showed large decreases at 3 weeks and 3 months following deafness. TRAAK and TASK-3 subunits showed significant decreases at 3 days and 3 weeks following deafness, but these differences were no longer significant at 3 months. Dramatic changes in expression of K-2PD(+), subunits suggest these channels may play a role in deafness-associated changes in the excitability of cochlear nucleus neurons. (c) 2006 Elsevier B.V. All rights reserved.