Pflügers Archiv - European Journal of Physiology

, Volume 467, Issue 12, pp 2437–2446 | Cite as

Inward rectifier potassium current (I K1) and Kir2 composition of the zebrafish (Danio rerio) heart

  • Minna HassinenEmail author
  • Jaakko Haverinen
  • Matt E. Hardy
  • Holly A. Shiels
  • Matti Vornanen
Ion channels, receptors and transporters


Electrophysiological properties and molecular background of the zebrafish (Danio rerio) cardiac inward rectifier current (IK1) were examined. Ventricular myocytes of zebrafish have a robust (−6.7 ± 1.2 pA pF−1 at −120 mV) strongly rectifying and Ba2+-sensitive (IC50 = 3.8 μM) IK1. Transcripts of six Kir2 channels (drKir2.1a, drKir2.1b, drKir2.2a, drKir2.2b, drKir2.3, and drKir2.4) were expressed in the zebrafish heart. drKir2.4 and drKir2.2a were the dominant isoforms in both the ventricle (92.9 ± 1.5 and 6.3 ± 1.5 %) and the atrium (28.9 ± 2.9 and 64.7 ± 3.0 %). The remaining four channels comprised together less than 1 and 7 % of the total transcripts in ventricle and atrium, respectively. The four main gene products (drKir2.1a, drKir2.2a, drKir2.2b, drKir2.4) were cloned, sequenced, and expressed in HEK cells for electrophysiological characterization. drKir2.1a was the most weakly rectifying (passed more outward current) and drKir2.2b the most strongly rectifying (passed less outward current) channel, whilst drKir2.2a and drKir2.4 were intermediate between the two. In regard to sensitivity to Ba2+ block, drKir2.4 was the most sensitive (IC50 = 1.8 μM) and drKir2.1a the least sensitive channel (IC50 = 132 μM). These findings indicate that the Kir2 isoform composition of the zebrafish heart markedly differs from that of mammalian hearts. Furthermore orthologous Kir2 channels (Kir2.1 and Kir2.4) of zebrafish and mammals show striking differences in Ba2+-sensitivity. Structural and functional differences needs to be taken into account when zebrafish is used as a model for human cardiac electrophysiology, cardiac diseases, and in screening cardioactive substances.


Zebrafish Heart Inward rectifier potassium current Kir2 channel 



The authors thank Nur Hidayah Jamar, Alex Leslie Thomas, and Robert Hallworth for their assistance with the zebrafish.


This study was supported by a grant from Jane and Aatos Erkko Foundation to MV (Project No. 64579) and the Leverhulme Trust to HAS (Project No. 240613).

Conflict of interest

The authors declare that they have no conflict of interest.


  1. 1.
    Alagem N, Dvir M, Reuveny E (2001) Mechanism of Ba2+ block of a mouse inwardly rectifying K+ channel: differential contribution by two discrete residues. J Physiol 534(2):381–393PubMedCentralCrossRefPubMedGoogle Scholar
  2. 2.
    Andersen CL, Jensen JL, Orntoft TF (2004) Normalization of real-time quantitative reverse transcription-PCR data: a model-based variance estimation approach to identify genes suited for normalization, applied to bladder and colon cancer data sets. Cancer Res 64:5245–5250. doi: 10.1158/0008-5472.CAN-04-0496 CrossRefPubMedGoogle Scholar
  3. 3.
    Anumonwo JMB, Lopatin AN (2010) Cardiac strong inward rectifier potassium channels. J Mol Cell Cardiol 48:45–54. doi: 10.1016/j.yjmcc.2009.08.013 PubMedCentralCrossRefPubMedGoogle Scholar
  4. 4.
    Arnaout R, Ferrer T, Huisken J, Spitzer K, Stainier DY, Tristani-Firouzi M, Chi NC (2007) Zebrafish model for human long QT syndrome. Proc Natl Acad Sci U S A 104:11316–11321PubMedCentralCrossRefPubMedGoogle Scholar
  5. 5.
    Brette F, Luxan G, Cros C, Dixey H, Wilson C, Shiels HA (2008) Characterization of isolated ventricular myocytes from adult zebrafish (Danio rerio). Biochem Biophys Res Commun 374:143–146. doi: 10.1016/j.bbrc.2008.06.109 PubMedCentralCrossRefPubMedGoogle Scholar
  6. 6.
    Briggs JP (2002) The zebrafish: a new model organism for integrative physiology. Am J Physiol 282:R3–R9Google Scholar
  7. 7.
    Chatelain FC, Alagem N, Xu Q, Pancarglu R, Reuveny E, Jr LMD (2005) The pore helix dipole has a minor role in inward rectifier channel function. Neuron 47:833–843PubMedCentralCrossRefPubMedGoogle Scholar
  8. 8.
    Chatelain FC, Gazzarrini S, Fujiwara Y, Arrigoni C, Domigan C, Ferrara G, Pantoja C, Thiel G, Moroni A, Minor DL Jr (2009) Selection of inhibitor-resistant viral potassium channels identifies a selectivity filter site that affects barium and amantadine block. PLoS One 4:e7496. doi: 10.1371/journal.pone.0007496 PubMedCentralCrossRefPubMedGoogle Scholar
  9. 9.
    Cortemeglia C, Beitinger TL (2005) Temperature tolerance of wild-type and red transgenic zebra danios. Trans Am Fish Soc 134:1431–1437CrossRefGoogle Scholar
  10. 10.
    Dhamoon AS, Jalife J (2005) The inward rectifier current (IK1) controls cardiac excitability and is involved in arrhythmogenesis. Heart Rhythm 2:316–324CrossRefPubMedGoogle Scholar
  11. 11.
    Dhamoon AS, Pandit SV, Sarmast F, Parisian KR, Guha P, Li Y, Bagwe S, Taffet SM, Anumonwo JMB (2004) Unique Kir2.x properties determine regional and species differences in the cardiac inward rectifier K+ current. Circ Res 94:1332–1339CrossRefPubMedGoogle Scholar
  12. 12.
    Eleawa SM, Sakr HF, Hussein AM, Assiri AS, Bayoumy NMK, Alkhateeb M (2013) Effect of testosterone replacement therapy on cardiac performance and oxidative stress in orchidectomized rats. Acta Physiol 209:136–147. doi: 10.1111/apha.12158 CrossRefGoogle Scholar
  13. 13.
    Gaborit N, Le Bouter S, Szuts V, Varro A, Escande D, Nattel S, Demolombe S (2007) Regional and tissue specific transcript signatures of ion channel genes in the non-diseased human heart. J Physiol 582:675–693PubMedCentralCrossRefPubMedGoogle Scholar
  14. 14.
    Galli GL, Lipnick MS, Block BA (2009) Effect of thermal acclimation on action potentials and sarcolemmal K+ channels from Pacific bluefin tuna cardiomyocytes. Am J Physiol 297:R502–R509. doi: 10.1152/ajpregu.90810.2008 Google Scholar
  15. 15.
    Hassinen M, Laulaja S, Paajanen V, Haverinen J, Vornanen M (2011) Thermal adaptation of the crucian carp (Carassius carassius) cardiac delayed rectifier current, IKs, by homomeric assembly of Kv7.1 subunits without MinK. Am J Physiol 301:R255–65. doi: 10.1152/ajpregu.00067.2011 CrossRefGoogle Scholar
  16. 16.
    Hassinen M, Paajanen V, Haverinen J, Eronen H, Vornanen M (2007) Cloning and expression of cardiac Kir2.1 and Kir2.2 channels in thermally acclimated rainbow trout. Am J Physiol 292:R2328–R2339Google Scholar
  17. 17.
    Hassinen M, Paajanen V, Vornanen M (2008) A novel inwardly rectifying K+ channel, Kir2.5, is upregulated under chronic cold stress in fish cardiac myocytes. J Exp Biol 211:2162–2171. doi: 10.1242/jeb.016121 CrossRefPubMedGoogle Scholar
  18. 18.
    Haverinen J, Hassinen M, Vornanen M (2007) Fish cardiac sodium channels are tetrodotoxin sensitive. Acta Physiol 191:197–204. doi: 10.1111/j.1748-1716.2007.01734.x CrossRefGoogle Scholar
  19. 19.
    Haverinen J, Vornanen M (2009) Responses of action potential and K+ currents to temperature acclimation in fish hearts: phylogeny or thermal preferences? Physiol Biochem Zool 82:468–482. doi: 10.1086/590223 CrossRefPubMedGoogle Scholar
  20. 20.
    Hibino H, Inanobe A, Furutani K, Murakami S, Findlay I, Kurachi Y (2010) Inwardly rectifying potassium channels: their structure, function and physiological role. Physiol Rev 90:291–366CrossRefPubMedGoogle Scholar
  21. 21.
    Hughes BA, Kumar G, Yuan Y, Swaminathan A, Yan D, Sharma A, Plumley L, Yang-Feng TL, Swaroop A (2000) Cloning and functional expression of human retinal Kir2.4, a pH-sensitive inwardly rectifying K+ channel. Am J Physiol 279:C771–84Google Scholar
  22. 22.
    Jaillon O, Aury J, Brunet F, Petit J, Stange-Thomann N, Mauceli E, Bouneau L, Fischer C, Ozouf-Costaz C, Bernot A et al (2004) Genome duplication in the teleost fish Tetraodon nigroviridis reveals the early vertebrate proto-karyotype. Nature 431:946–957CrossRefPubMedGoogle Scholar
  23. 23.
    Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Buxton S, Cooper A, Markowitz S, Duran C et al (2012) Geneious Basic: an integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics 28:1647–1649. doi: 10.1093/bioinformatics/bts199 PubMedCentralCrossRefPubMedGoogle Scholar
  24. 24.
    Leong IUS, Skinner JR, Shelling AN, Love DR (2014) Expression of a mutant kcnj2 gene transcript in zebrafish. ISRN Mol Biol 324839:1–14CrossRefGoogle Scholar
  25. 25.
    Liu GX, Derst C, Schlichthorl G, Heinen S, Seebohm G, Bruggemann A, Kummer W, Veh RW, Daut J, Preisig-Muller R (2001) Comparison of cloned Kir2 channels with native inward rectifier K+ channels from guinea-pig cardiomyocytes. J Physiol 532:115–126CrossRefPubMedGoogle Scholar
  26. 26.
    Melnyk P, Zhang L, Shrier A, Nattel S (2002) Differential distribution of Kir2.1 and Kir2.3 subunits in canine atrium and ventricle. Am J Physiol 283:H1123–H1133Google Scholar
  27. 27.
    Nguyen CT, Lu Q, Wang Y, Chen JN (2008) Zebrafish as a model for cardiovascular development and disease. Drug Discov Today Dis Models 5:135–140. doi: 10.1016/j.ddmod.2009.02.003 PubMedCentralCrossRefPubMedGoogle Scholar
  28. 28.
    Panama BK, Lopatin AN (2006) Differential polyamine sensitivity in inwardly rectifying Kir2 potassium channels. J Physiol 571:287–302PubMedCentralCrossRefPubMedGoogle Scholar
  29. 29.
    Pfaffl MW, Tichopad A, Prgomet C, Neuvians TP (2004) Determination of stable housekeeping genes, differentially regulated target genes and sample integrity: bestkeeper–Excel-based tool using pair-wise correlations. Biotechnol Lett 26:509–515CrossRefPubMedGoogle Scholar
  30. 30.
    Ryan DP, da Silva MR, Soong TW, Fontaine B, Donaldson MR, Kung AW, Jongjaroenprasert W, Liang MC, Khoo DH, Cheah JS et al (2010) Mutations in potassium channel Kir2.6 cause susceptibility to thyrotoxic hypokalemic periodic paralysis. Cell 140:88–98. doi: 10.1016/j.cell.2009.12.024 PubMedCentralCrossRefPubMedGoogle Scholar
  31. 31.
    Sambrook J, Fritsch EF, Maniatis T (1989) Molecular cloning: a laboratory manual. Cold Spring Harbor Laboratory Press, New York, p. 9.14–9.19Google Scholar
  32. 32.
    Schartl M (2014) Beyond the zebrafish: diverse fish species for modeling human disease. Dis Model Mech 7:181–192. doi: 10.1242/dmm.012245 PubMedCentralCrossRefPubMedGoogle Scholar
  33. 33.
    Schram G, Pourrier M, Wang Z, White M, Nattel S (2003) Barium block of Kir2 and human cardiac inward rectifier currents: evidence for subunit-heteromeric contribution to native currents. Cardiovasc Res 59:328–338CrossRefPubMedGoogle Scholar
  34. 34.
    Shyng SL, Sha Q, Ferrigni T, Lopatin AN, Nichols CG (1996) Depletion of intracellular polyamines relieves inward rectification of potassium channels. Proc Natl Acad Sci U S A 93:12014–12019PubMedCentralCrossRefPubMedGoogle Scholar
  35. 35.
    Silver N, Best S, Jiang J, Thein SL (2006) Selection of housekeeping genes for gene expression studies in human reticulocytes using real-time PCR. BMC Mol Biol 7:33PubMedCentralCrossRefPubMedGoogle Scholar
  36. 36.
    Szuts V, Menesi D, Varga-Orvos Z, Zvara A, Houshmand N, Bitay M, Bogats G, Virag L, Baczko I, Szalontai B et al (2013) Altered expression of genes for Kir ion channels in dilated cardiomyopathy. Can J Physiol Pharmacol 91:648–656. doi: 10.1139/cjpp-2012-0413 CrossRefPubMedGoogle Scholar
  37. 37.
    Taggart P, Sutton PMI, Boyett MR, Lab M, Swanton H (1996) Human ventricular action potential duration during short and long cycles. Am J Physiol 94:2526–2534Google Scholar
  38. 38.
    Tennant BP, Cui Y, Tinker A, Clapp LH (2006) Functional expression of inward rectifier potassium channels in cultured human pulmonary smooth muscle cells: evidence for a major role of Kir2.4 subunits. J Membr Biol 213:19–29. doi: 10.1007/s00232-006-0037-y PubMedCentralCrossRefPubMedGoogle Scholar
  39. 39.
    Töpert C, Doring F, Wischmeyer E, Karschin C, Brockhaus J, Ballanyi K, Derst C, Karschin A (1998) Kir2.4: a novel K+ inward rectifier channel associated with motoneurons of cranial nerve nuclei. J Neurosci 18:4096–4105PubMedGoogle Scholar
  40. 40.
    Tristani-Firouzi M, Etheridge SP (2010) Kir 2.1 channelopathies: the Andersen-Tawil syndrome. Pflugers Arch 460:289–294. doi: 10.1007/s00424-010-0820-6 CrossRefPubMedGoogle Scholar
  41. 41.
    Tu S, Chi NC (2012) Zebrafish models in cardiac development and congenital heart birth defects. Differentiation 84:4–16. doi: 10.1016/j.diff.2012.05.005 PubMedCentralCrossRefPubMedGoogle Scholar
  42. 42.
    Vandesompele J, De Preter K, Pattyn F, Poppe B, Van Roy N, De Paepe A, Speleman F (2002) Accurate normalization of real-time quantitative RT-PCR data by geometric averaging of multiple internal control genes. Genome Biol 3:RESEARCH0034Google Scholar
  43. 43.
    Volff JN (2005) Genome evolution and biodiversity in teleost fish. Heredity 94:280–294CrossRefPubMedGoogle Scholar
  44. 44.
    Vornanen M, Hassinen M, Haverinen J (2011) Tetrodotoxin sensitivity of the vertebrate cardiac Na+ current. Mar Drugs 9:2409–2422PubMedCentralCrossRefPubMedGoogle Scholar
  45. 45.
    Vornanen M, Haverinen J, Egginton S (2014) Acute heat tolerance of cardiac excitation in the brown trout (Salmo trutta fario). J Exp Biol 217:299–309. doi: 10.1242/jeb.091272 CrossRefPubMedGoogle Scholar
  46. 46.
    Zaritsky JJ, Redell JB, Tempel BL, Schwarz TL (2001) The consequences of disrupting cardiac inwardly rectifying K+ current (IK1) as revealed by the targeted deletion of the murine Kir2.1 and Kir2.2 genes. J Physiol 533(3):697–710PubMedCentralCrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Minna Hassinen
    • 1
    Email author
  • Jaakko Haverinen
    • 1
  • Matt E. Hardy
    • 2
  • Holly A. Shiels
    • 2
  • Matti Vornanen
    • 1
  1. 1.Department of BiologyUniversity of Eastern FinlandJoensuuFinland
  2. 2.Faculty of Life SciencesUniversity of ManchesterManchesterUK

Personalised recommendations