A Non-Specific K+ Channel Blocker
    Cat #: A-115
    Alternative Name 4-AP
  • Lyophilized Powder
  • Bioassay Tested
  • Source Synthetic
    MW: 94.1
    Purity: >99% (HPLC)
    Effective concentration IC50 ~ 0.1-18 mM.
    • 4-Aminopyridine
    Chemical name 4-Aminopyridine.
    Molecular formula C5H6N2.
    CAS No.: 504-24-5.
    Activity 4-Aminopyridine is a non-selective KV channel blocker1, which blocks nearly all KV currents although its potency varies over a wide range2. It blocks KV2.1 and KV3.1 channels with IC50 of 18 and 0.1 mM, respectively, in oocytes2. KV1.1 and KV1.2 channels are blocked by 4-AP with IC50 of 147 μM and 230 μM, respectively, in CHO cells1. It has also been used in the clinic to manage some of the symptoms of Multiple Sclerosis3.
    1. Perreault, P. et al. (1991) J. Neurophysiol. 65, 771.
    2. Stephens, G.J. et al. (1994) J. Physiol. 477, 187.
    3. Kirsch, G.E. et al. (1993) Neuron 11, 503.
    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 Water. Centrifuge all product preparations before use (10000 x g 5 min).
    Storage of solutions Up to one week at 4°C or six months at -20°C.
    Our bioassay
    • 4-Aminopyridine
      Alomone Labs 4-Aminopyridine blocks KV1.2 channel currents heterologously expressed in Xenopus oocytes.
      A. Time course of current reversible inhibition by 1 mM 4-Aminopyridine (#A-115) (as extracted from the ramp response at 60 mV). B. Example traces of KV1.2 currents in response to 200 sec ramp depolarization (from -80 mV to 60 mV during 100 msec) before and during 1 mM 4-Aminopyridine application.
    References - Scientific background
    1. Roeper, J. et al. (1996) Curr. Opin Neurobiol. 6, 338.
    2. Mathie, A. et al. (1998) Gen. Pharmacol. 30, 13.
    3. Stephens, G.J. et al. (1994) J. Physiol. 477, 187.
    4. Tseng, G.N. et al. (1996) J. Pharmacol. Exp. Ther. 279, 865.
    5. Kirsch, G.E. et al. (1993) Neuron 11, 503.
    6. Martin, R. et al. (1992) Annu. Rev. Immunol. 10, 153.
    7. Rasband, M.N. et al. (1998) J. Neurosci. 18, 36.
    Scientific background

    Voltage-gated K+ channels (KV) play an important role in a number of different aspects of electrical responses of the nervous system. Their activity determines the frequency of action potentials and the shape of the action potential waveform. Furthermore, KV channels may regulate the excitability of individual neurons and may control the strength of synaptic contacts between neurons1,2.

    4-Aminopyridine (4-AP) is a non-selective KV channel blocker3, which can block a wide variety of KV channels with different state dependencies4. Therefore, in search for clues for the structural determinants of KV channels that are important for the state dependencies of drug-channel interactions, 4-AP serves as a useful tool. For example, it blocks KV2.1 and KV3.1 channels with IC50s of 18 and 0.1 mM, respectively, in oocytes5. KV1.1 and KV1.2 channels are blocked by 4-AP with IC50s of 147 µM and 230 µM, respectively, in CHO cells3.

    Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system, characterized by axonal conduction block6. 4-AP has been tested as a symptomatic treatment in patients with MS based on the clinical rationale that neurological function could be improved by overcoming conduction block in demyelinated axons present in MS lesions. Indeed, 4-AP restored conduction in experimentally demyelinated nerves in the peripheral nervous system7. In addition, 4-AP increased presynaptic action potential duration and amplitude leading to enhanced transmitter release8.

    Target KV K+ channels
    Last update: 24/01/2020

    4-Aminopyridine (#A-115) is a highly pure, synthetic, and biologically active compound.

    For research purposes only, not for human use
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