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Expression and function of KCNQ channels in larval zebrafish
Author(s) -
Chege Sally W.,
Hortopan Gabriela A.,
T. Dinday Matthew,
Baraban Scott C.
Publication year - 2012
Publication title -
developmental neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.716
H-Index - 129
eISSN - 1932-846X
pISSN - 1932-8451
DOI - 10.1002/dneu.20937
Subject(s) - zebrafish , biology , neuroscience , morpholino , potassium channel , electrophysiology , nervous system , microbiology and biotechnology , genetics , endocrinology , gene
Members of the K v 7 family generate a subthreshold potassium current, termed M‐current, that regulates the excitability of principal central neurons. Mutations in two members of this family, K v 7.2 ( KCNQ2 ) and K v 7.3 ( KCNQ3 ) are associated with a neurological disorder known as benign familial neonatal convulsion (BFNC). Despite their importance in normal and pathological brain function, developmental expression and function of these channels remains relatively unexplored. Here, we examined the temporal expression of K v 7 channel subunits in zebrafish larvae using a real‐time quantitative PCR approach. Spatial expression in the larval zebrafish brain was assessed using whole‐mount in situ hybridization. The mRNA for three members of the K v 7 family ( KCNQ2, 3 and 5 ) is reported in zebrafish between two and seven days post‐fertilization (dpf). Using electrophysiological techniques, we show that inhibitors of K v 7 channels (linopirdine and XE991) induce burst discharge activity in immature zebrafish between 3 and 7 dpf. This abnormal electrical activity is blocked by a K v 7 channel opener (retigabine) and was also shown to evoke convulsive behaviors in freely swimming zebrafish. Using morpholino oligonucleotides directed against KCNQ3 , we confirmed a role for KCNQ channels in generation of electrical burst discharges. These results indicate that functional K v 7 channels are expressed in the larval zebrafish nervous system and could play a direct role in generation of seizure activity. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 72: 186–198, 2012