Skip to main content
Log in

BKβ1 Subunits Contribute to BK Channel Diversity in Rat Hypothalamic Neurons

  • Original Research
  • Published:
Cellular and Molecular Neurobiology Aims and scope Submit manuscript

Abstract

Large conductance Ca2+-activated BK channels are important regulators of action potential duration and firing frequency in many neurons. As the pore-forming subunits of BK channels are encoded by a single gene, channel diversity is mainly generated by alternative splicing and interaction with auxiliary β-subunits (BKβ1-4). In hypothalamic neurons several BK channel subtypes have been described electrophysiologically; however, the distribution of BKβ subunits is unknown so far. Therefore, an antibody against the large extracellular loop of the BKβ1 subunit was raised, freed from cross-reactivity against BKβ2-4 and affinity-purified. The resulting polyclonal monospecific BKβ1 antibody was characterized by Western blot analysis, ELISA techniques and immunocytochemical staining of BKβ1-4-transfected CHO and COS-1 cells. Regional and cellular distribution in the rat hypothalamus was analysed by immunocytochemistry and in situ hybridization experiments. Immunocytochemical staining of rat hypothalamic neurons indicates strong BKβ1 expression in the supraoptic nucleus and the magno- and parvocellular parts of the paraventricular nucleus. Lower expression was found in periventricular nucleus, the arcuate nucleus and in the median eminence. Immunostaining was predominantly localized to somata. In addition, pericytes and ependymal epithelial cells showed BKβ1 labelling. In all cases immunocytochemical results were supported by in situ hybridization.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9

Similar content being viewed by others

References

  • Bao L, Cox DH (2005) Gating and ionic currents reveal how the BKCa channel’s Ca2+ sensitivity is enhanced by its beta1 subunit. J Gen Physiol 126:393–412

    Article  CAS  PubMed  Google Scholar 

  • Behrens R, Nolting A, Reimann F, Schwarz M, Waldschütz R, Pongs O (2000) hKCNMB3 and hKCNMB4, cloning and characterization of two members of the large-conductance calcium-activated potassium channel beta subunit family. FEBS Lett 474:99–106

    Article  CAS  PubMed  Google Scholar 

  • Berkefeld H, Sailer CA, Bildl W, Rohde V, Thumfart JO, Eble S, Klugbauer N, Reisinger E, Bischofberger J, Oliver D, Knaus HG, Schulte U, Fakler B (2006) BKCa-Cav channel complexes mediate rapid and localized Ca2+-activated K+ signaling. Science 314:615–620

    Article  CAS  PubMed  Google Scholar 

  • Brenner R, Jegla TJ, Wickenden A, Liu Y, Aldrich RW (2000a) Cloning and functional characterization of novel large conductance calcium-activated potassium channel beta subunits, hKCNMB3 and hKCNMB4. J Biol Chem 275:6453–6461

    Article  CAS  PubMed  Google Scholar 

  • Brenner R, Peréz GJ, Bonev AD, Eckman DM, Kosek JC, Wiler SW, Patterson AJ, Nelson MT, Aldrich RW (2000b) Vasoregulation by the beta1 subunit of the calcium-activated potassium channel. Nature 407:870–876

    Article  CAS  PubMed  Google Scholar 

  • Brunton PJ, Sausbier M, Wietzorrek G, Sausbier U, Knaus HG, Russell JA, Ruth P, Shipston MJ (2007) Hypothalamic–pituitary–adrenal axis hyporesponsiveness to restraint stress in mice deficient for large-conductance calcium- and voltage-activated potassium (BK) channels. Endocrinology 148:5496–5506

    Article  CAS  PubMed  Google Scholar 

  • Chang CP, Dworetzky SI, Wang J, Goldstein ME (1997) Differential expression of the alpha and beta subunits of the large-conductance calcium-activated potassium channel: implication for channel diversity. Brain Res Mol Brain Res 45:33–40

    Article  CAS  PubMed  Google Scholar 

  • Derst C, Walther C, Veh RW, Wicher D, Heinemann SH (2006) Four novel sequences in Drosophila melanogaster homologous to the auxiliary Para sodium channel subunit TipE. Biochem Biophys Res Commun 339:939–948

    Article  CAS  PubMed  Google Scholar 

  • Dopico AM, Widmer H, Wang G, Lemos JR, Treistman SN (1999) Rat supraoptic magnocellular neurones show distinct large conductance, Ca2+-activated K+ channel subtypes in cell bodies versus nerve endings. J Physiol 519:101–114

    Article  CAS  PubMed  Google Scholar 

  • Eulitz D, Prüss H, Derst C, Veh RW (2007) Heterogeneous distribution of kir3 potassium channel proteins within dopaminergic neurons in the mesencephalon of the rat brain. Cell Mol Neurobiol 27:285–302

    Article  CAS  PubMed  Google Scholar 

  • Geisler S, Heilmann H, Veh RW (2002) An optimized method for simultaneous demonstration of neurons and myelinated fiber tracts for delineation of individual trunco- and palliothalamic nuclei in the mammalian brain. Histochem Cell Biol 117:69–79

    Article  CAS  PubMed  Google Scholar 

  • Gruber A, Zingales B (1995) Alternative method to remove antibacterial antibodies from antisera used for screening of expression libraries. Biotechniques 19:28–30

    CAS  PubMed  Google Scholar 

  • Hanner M, Vianna-Jorge R, Kamassah A, Schmalhofer WA, Knaus HG, Kaczorowski GJ, Garcia ML (1998) The beta subunit of the high conductance calcium-activated potassium channel. Identification of residues involved in charybdotoxin binding. J Biol Chem 273:16289–16296

    Article  CAS  PubMed  Google Scholar 

  • Harlow E, Lane D (eds) (1988) Antibodies: a laboratory manual. CSH Laboratory Press, Cold Spring Harbor, NY

    Google Scholar 

  • Joux N, Chevaleyre V, Alonso G, Boissin-Agasse L, Moos FC, Desarménien MG, Hussy N (2001) High voltage-activated Ca2+ currents in rat supraoptic neurones: biophysical properties and expression of the various channel alpha1 subunits. J Neuroendocrinol 13:638–649

    Article  CAS  PubMed  Google Scholar 

  • Kadekaro M, Su G, Chu R, Lei Y, Li J, Fang L (2006) Nitric oxide up-regulates the expression of calcium-dependent potassium channels in the supraoptic nuclei and neural lobe of rats following dehydration. Neurosci Lett 404:50–55

    Article  CAS  PubMed  Google Scholar 

  • Kent J, Meredith AL (2008) BK channels regulate spontaneous action potential rhythmicity in the suprachiasmatic nucleus. PLoS One 3:e3884

    Article  PubMed  Google Scholar 

  • Knaus HG, Garcia-Calvo M, Kaczorowski GJ, Garcia ML (1994) Subunit composition of the high conductance calcium-activated potassium channel from smooth muscle, a representative of the mSlo and slowpoke family of potassium channels. J Biol Chem 269:3921–3924

    CAS  PubMed  Google Scholar 

  • Knaus HG, Schwarzer C, Koch RO, Eberhart A, Kaczorowski GJ, Glossmann H, Wunder F, Pongs O, Garcia ML, Sperk G (1996) Distribution of high-conductance Ca2+-activated K+ channels in rat brain: targeting to axons and nerve terminals. J Neurosci 16:955–963

    CAS  PubMed  Google Scholar 

  • Lovell PV, McCobb DP (2001) Pituitary control of BK potassium channel function and intrinsic firing properties of adrenal chromaffin cells. J Neurosci 21:3429–3442

    CAS  PubMed  Google Scholar 

  • McManus OB, Helms LM, Pallanck L, Ganetzky B, Swanson R, Leonard RJ (1995) Functional role of the beta subunit of high conductance calcium-activated potassium channels. Neuron 14:645–650

    Article  CAS  PubMed  Google Scholar 

  • Pietrzykowski AZ, Martin GE, Puig SI, Knott TK, Lemos JR, Treistman SN (2004) Alcohol tolerance in large-conductance, calcium-activated potassium channels of CNS terminals is intrinsic and includes two components: decreased ethanol potentiation and decreased channel density. J Neurosci 24:8322–8332

    Article  CAS  PubMed  Google Scholar 

  • Plüger S, Faulhaber J, Fürstenau M, Löhn M, Waldschütz R, Gollasch M, Haller H, Luft FC, Ehmke H, Pongs O (2000) Mice with disrupted BK channel beta1 subunit gene feature abnormal Ca2+ spark/STOC coupling and elevated blood pressure. Circ Res 87:E53–E60

    PubMed  Google Scholar 

  • Pompeia C, Ortis F, Armelin MC (1996) Immunopurification of polyclonal antibodies to recombinant proteins of the same gene family. Biotechniques 21:986–990

    CAS  PubMed  Google Scholar 

  • Pradidarcheep W, Labruyère WT, Dabhoiwala NF, Lamers WH (2008) Lack of specificity of commercially available antisera: better specifications needed. J Histochem Cytochem 56:1099–1111

    Article  CAS  PubMed  Google Scholar 

  • Salkoff L, Butler A, Ferreira G, Santi C, Wei A (2006) High-conductance potassium channels of the SLO family. Nat Rev Neurosci 7:921–931

    Article  CAS  PubMed  Google Scholar 

  • Saper CB (2009) A guide to the perplexed on the specificity of antibodies. J Histochem Cytochem 57:1–5

    Article  CAS  PubMed  Google Scholar 

  • Sausbier U, Sausbier M, Sailer CA, Arntz C, Knaus HG, Neuhuber W, Ruth P (2006) Ca2+-activated K+ channels of the BK-type in the mouse brain. Histochem Cell Biol 125:725–741

    Article  CAS  PubMed  Google Scholar 

  • Uebele VN, Lagrutta A, Wade T, Figueroa DJ, Liu Y, McKenna E, Austin CP, Bennett PB, Swanson R (2000) Cloning and functional expression of two families of beta-subunits of the large conductance calcium-activated K+ channel. J Biol Chem 275:23211–23218

    Article  CAS  PubMed  Google Scholar 

  • Valverde MA, Rojas P, Amigo J, Cosmelli D, Orio P, Bahamonde MI, Mann GE, Vergara C, Latorre R (1999) Acute activation of Maxi-K channels (hSlo) by estradiol binding to the beta subunit. Science 285:1929–1931

    Article  CAS  PubMed  Google Scholar 

  • Veh RW, Lichtinghagen R, Sewing S, Wunder F, Grumbach IM, Pongs O (1995) Immunohistochemical localization of five members of the Kv1 channel subunits: contrasting subcellular locations and neuron-specific co-localizations in rat brain. Eur J Neurosci 7:2189–2205

    Article  CAS  PubMed  Google Scholar 

  • Wynne PM, Puig SI, Martin GE, Treistman SN (2009) Compartmentalized beta subunit distribution determines characteristics and ethanol sensitivity of somatic, dendritic, and terminal large-conductance calcium-activated potassium channels in the rat central nervous system. J Pharmacol Exp Ther 329:978–986

    Article  CAS  PubMed  Google Scholar 

  • Yang CT, Zeng XH, Xia XM, Lingle CJ (2009) Interactions between beta subunits of the KCNMB family and Slo3: beta4 selectively modulates Slo3 expression and function. PLoS One 4:e6135

    Google Scholar 

Download references

Acknowledgements

We are indebted to Heike Heilmann, Ina Wolter and Sema Ünsal for technical help. In addition, we would like to thank Annett Kaphahn for editorial help.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Christian Derst.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Salzmann, M., Seidel, K.N., Bernard, R. et al. BKβ1 Subunits Contribute to BK Channel Diversity in Rat Hypothalamic Neurons. Cell Mol Neurobiol 30, 967–976 (2010). https://doi.org/10.1007/s10571-010-9527-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10571-010-9527-7

Keywords

Navigation