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Description: KCa2 (SK) channel blocker

Purity: ≥95%

Product Details
Citations (23)

Biological Activity

Apamin is a prototypical potent and highly selective inhibitor of the small-conductance Ca2+-activated K+-channel (KCa2, SK). Blocks medium after-hyperpolarization in vitro and is brain penetrant and convulsive in vivo.

Technical Data


(Modifications: Disulfide bridges: 1-11, 3-15, His-18 = C-terminal amide)

Soluble to 1 mg/ml in water
Store at -20°C

The technical data provided above is for guidance only. For batch specific data refer to the Certificate of Analysis.
Tocris products are intended for laboratory research use only, unless stated otherwise.

Background References

  1. Apamin.
    Pharmacol.Ther., 1984;25:255
  2. Matching molecules to function: neuronal Ca2+-activated K+ channels and afterhyperpolarizations.
    Stocker et al.
    Toxicon, 2004;43:933
  3. Potassium channel toxins.
    Pharmacol.Ther., 1990;46:137
  4. Behavioral effects of apamin, a selective inhibitor of the SKCa-channel, in mice and rats.
    van der Staay et al.
    Neurosci.Biobehav.Rev., 1999;23:1087

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Citations for Apamin

The citations listed below are publications that use Tocris products. Selected citations for Apamin include:

23 Citations: Showing 1 - 10

  1. TRPM4 Conductances in Thalamic Reticular Nucleus Neurons Generate Persistent Firing during Slow Oscillations.
    Authors: O'Malley Et al.
    J Neurosci  2020;40:4813
  2. Functional Coupling of Cav2.3 and BK Potassium Channels Regulates Action Potential Repolarization and Short-Term Plasticity in the Mouse Hippocampus.
    Authors: Gutzmann Et al.
    Front Cell Neurosci  2019;13:27
  3. Activation of TREK currents by riluzole in three subgroups of cultured mouse nodose ganglion neurons.
    Authors: Fernandez-Fernandez Et al.
    PLoS One  2018;13:e0199282
  4. Bidirectional Modulation of Intrinsic Excitability in Rat Prelimbic Cortex Neuronal Ensembles and Non-Ensembles after Operant Learning.
    Authors: Whitaker Et al.
    J Neurosci  2017;37:8845
  5. Chronic social isolation reduces 5-HT neuronal activity via upregulated SK3 calcium-activated potassium channels
    Authors: Sargin Et al.
    Elife  2016;5:e21416
  6. Cyclooxygenase-2 inhibition reduces stress-induced affective pathology.
    Authors: Gamble-George Et al.
    Elife  2016;5
  7. Cell type-specific transcriptomics of hypothalamic energy-sensing neuron responses to weight-loss.
    Authors: Henry Et al.
    Mol Pain  2015;4
  8. Increased Basolateral Amygdala Pyramidal Cell Excitability May Contribute to the Anxiogenic Phenotype Induced by Chronic Early-Life Stress.
    Authors: Rau Et al.
    Heart Rhythm  2015;35:9730
  9. Re-Emergent Inhibition of Cochlear Inner Hair Cells in a Mouse Model of Hearing Loss.
    Authors: Zachary and Fuchs
    J Neurosci  2015;35:9701
  10. The role of K+ conductances in regulating membrane excitability in human gastric corpus smooth muscle.
    Authors: Lee Et al.
    FASEB J  2015;308:G625
  11. Small-conductance calcium-activated potassium (SK) channels in the amygdala mediate pain-inhibiting effects of clinically available R.zole in a rat model of arthritis pain.
    Authors: Thompson Et al.
    J Neurosci  2015;11:51
  12. Apamin does not inhibit human cardiac Na+ current, L-type Ca2+ current or other major K+ currents.
    Authors: Yu Et al.
    J Neurosci  2014;9:e96691
  13. Amiodarone inhibits apamin-sensitive potassium currents.
    Authors: Turker Et al.
    PLoS One  2013;8:e70450
  14. Synaptic NMDA receptor-dependent Ca2+ entry drives membrane potential and Ca2+ oscillations in spinal ventral horn neurons.
    Authors: Alpert and Alford
    PLoS One  2013;8:e63154
  15. Proarrhythmic effect of blocking the small conductance calcium activated potassium channel in isolated canine left atrium.
    Authors: Hsueh Et al.
    Elife  2013;10:891
  16. Asynchronous Ca2+ current conducted by voltage-gated Ca2+ (CaV)-2.1 and CaV2.2 channels and its implications for asynchronous neurotransmitter release.
    Authors: Few Et al.
    Proc Natl Acad Sci U S A  2012;109:E452
  17. Dynamic interplay of excitatory and inhibitory coupling modes of neuronal L-type calcium channels.
    Authors: Geier Et al.
    Am J Physiol Cell Physiol  2011;300:C937
  18. Relaxin causes selective outward remodeling of brain parenchymal arterioles via activation of peroxisome proliferator-activated receptor-γ.
    Authors: Chan and Cipolla
    Sci Rep  2011;25:3229
  19. Postnatal expression of an apamin-sensitive k(ca) current in vestibular calyx terminals.
    Authors: Meredith Et al.
    J Membr Biol  2011;244:81
  20. NE causes a biphasic change in mammalian pinealocye membrane potential: role of alpha1B-adrenoreceptors, phospholipase C, and Ca2+.
    Authors: Zemkova Et al.
    Endocrinology  2011;152:3842
  21. Visinin-like neuronal calcium sensor proteins regulate the slow calcium-activated afterhyperpolarizing current in the rat cerebral cortex.
    Authors: Villalobos and Andrade
    Am J Physiol Gastrointest Liver Physiol  2010;30:14361
  22. Allosteric block of KCa2 channels by apamin.
    Authors: Lamy Et al.
    J Neurosci  2010;285:27067
  23. DArgic modulation of spinal neuronal excitability.
    Authors: Han Et al.
    J Biol Chem  2007;27:13192


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