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A Mycotoxin Blocker of KCa1.1 (BK) Channels and SERCA Pumps

Cat #: P-450
Lyophilized Powder yes
  • Bioassay Tested
  • Origin Penicillium paxilli.
    Source Natural
    MW: 435.6
    Purity: >98% (HPLC)
    Effective concentration 10-100 nM.
    Chemical name (2R,4bS,6aS,12bS,12cR,14aS)-5,6,6a,7,12,12b,12c,13,14,1 4a-Decahydro-4b-hydroxy-2-(1-hydroxy-1-methylethyl)-12b ,12c-dimethyl-2H-pyrano[2'',3'':5',6']benz[1',2':6,7]in deno[1,2-b]indol-3(4bH)-one.
    Molecular formula C27H33NO4.
    CAS No.: 57186-25-1
    Activity Paxilline is a selective blocker of high-conductance Ca2+-activated (Maxi-K) K+ channels.
    Shipping and storage Shipped at room temperature. Product as supplied can be stored intact at room temperature for several weeks. For longer periods, it should be stored at -20°C.
    Solubility DMSO or acetone. Centrifuge all product preparations before use (10000 x g 5 min).
    Storage of solutions Up to one week at 4°C or three months at -20°C.
    Our bioassay
    • Alomone Labs Paxilline inhibits KCa1.1 (BK) channels heterologously expressed in Xenopus oocytes.
      Alomone Labs Paxilline inhibits KCa1.1 (BK) channels heterologously expressed in Xenopus oocytes.
      Left: The effect of 100 nM Paxilline (#P-450) (a), Penitrem A (P-650) (b), and Verruculogen (#V-500) (c) on BK currents. Time course of current amplitude changes upon sequential application of the three toxins. Right: Example of current responses to 100 ms depolarization before (red) and during (black) perfusion of 500 nM Paxilline.
    References - Scientific background
    1. Selala, M.I. et al. (1991) J. Nat. Prod54, 207.
    2. Knaus, H.G. et al. (1994) Biochemistry 33, 5819.
    3. Modulator Issue No. 17.pdf
    4. Hu, H.  et al. (2001) J. Neurosci. 21, 9585.
    5. Faber, E.S. and Sah, P. (2002) J. Neurosci. 22, 1618.
    6. Bilmen, J.G. et al. (2002) Arch. Biochem. Biophys. 406, 55.
    Scientific background

    Paxilline is a selective blocker of KCa1.1 (high-conductance Ca2+-activated K+, BK) channels. It belongs to a set of tremorgenic indole alkaloids which are lipid soluble and also include Penitrem A and Verruculogen.2

    Paxilline enhanced the electrically induced twitch contractions in guinea pig ileum, without influencing the contractions provoked by exogenous acetylcholine.1 Paxilline was shown to inhibit the peptidyle toxin resistant combination a+b4 channels (for more background see 3) expressed in CHO cells.4 It was shown to be as potent as Iberiotoxin in action potential broadening in hippocampus and amygdala.4,5

    Paxilline also inhibits intracellular Ca2+-ATPases (SERCA) with IC50s between 5 and 10 µM6.

    Target KCa K+ channels, SERCA pump
    Image & Title Paxilline
    Alomone Labs Paxilline inhibits KCa1.1 channel currents in isolated canine intracardiac neurons.Representative current traces show a total blockage of the fast-activated current component and a reduction of the slow outward component caused by 100 nM Paxilline (#P-450).Adapted from Perez, G.J. et al. (2013) Am. J. Physiol. 304, C280. with permission of The American Physiological Society.
    Last update: 06/11/2022

    Paxilline (#P-450) is a highly pure, natural, and biologically active compound.

    For research purposes only, not for human use



    Product citations
    1. Iordache, F. et al. (2016) J. Physiol. Sci. 66, 463.
    2. Zhang, Y.Y. et al. (2014) J. Cell. Phys. 229, 202.
    3. Chen, M. et al. (2013) Mol. Neurobiol. 48, 794.
    4. Perez, G.J. et al. (2013) Am. J. Physiol. 304, C280.
    5. Keating, N. and Quinlan, L.R. (2012) Am. J. Physiol. 302, C100.
    6. Ishii, H. et al. (2010) Eur. J. Neurosci. 32, 736.
    7. Henney, N.C. et al. (2009) Am. J. Physiol. 297, C1397.
    8. Griguoli, M. et al. (2009) Eur. J. Neurosci. 30, 1011.
    9. Benhassine, N. and Berger, T. (2009) Pflugers Arch. 457, 1133.
    10. Liu, Y.C. et al. (2009) Naunyn-Schmiedeberg's Arch. Pharmacol. 379, 127.
    11. Wu, S.N. et al. (2008) Mol. Pharmacol. 74, 1696.


    Scientific Background

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