Abstract
Two-pore domain potassium (K-2P) channel expression is believed to underlie the developmental emergence of a potassium leak conductance [IK(SO)] in cerebellar granule neurons (CGNs), suggesting that K-2P function is an important determinant of the input conductance and resting membrane potential. To investigate the role that different K-2P channels may play in the regulation of CGN excitability, we generated a mouse lacking TASK-1, a K-2P channel known to have high expression levels in CGNs. In situ hybridization and real-time PCR studies in wild-type and TASK-1 knock-outs (KOs) demonstrated that the expression of other K2P channels was unaltered in CGNs. TASK-1 knock-out mice were healthy and bred normally but exhibited compromised motor performance consistent with altered cerebellar function. Whole-cell recordings from adult cerebellar slice preparations revealed that the resting excitability of mature CGNs was no different in TASK-1 KO and littermate controls. However, the modulation of I-K(SO) by extracellular Zn2+, ruthenium red, and H+ was altered. The I-K(SO) recorded from TASK-1 knock-out CGNs was no longer sensitive to alkalization and was blocked by Zn2+ and ruthenium red. These results suggest that a TASK-1-containing channel population has been replaced by a homodimeric TASK-3 population in the TASK-1 knock-out. These data directly demonstrate that TASK-1 channels contribute to the properties of I-K(SO) in adult CGNs. However, TASK channel subunit composition does not alter the resting excitability of CGNs but does influence sensitivity to endogenous modulators such as Zn2+ and H+.
Original language | English |
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Pages (from-to) | 11455-11467 |
Number of pages | 12 |
Journal | Journal of Neuroscience |
Volume | 25 |
Issue number | 49 |
DOIs | |
Publication status | Published - Dec 2005 |
Keywords
- potassium channels
- cerebellum
- motor control
- patch-clamp
- knock-out mice
- excitability
- DOMAIN POTASSIUM CHANNEL
- BACKGROUND K+ CHANNEL
- FUNCTIONAL EXPRESSION
- RECEPTOR ACTIVATION
- GABA(A) RECEPTORS
- CELLS
- RAT
- MICE
- INHIBITION
- PHARMACOLOGY