Catalog Number: 0751
Chemical Name: (±)-Tropanyl 2-(4-chlorophenoxy)butanoate maleate
Biological Activity
Potent and selective σ2 antagonist with central effects following systemic administration. Causes increased release of acetylcholine at central muscarinic synapses. Potent analgesic (efficacy comparable to morphine) and nootropic agent.
Technical Data
  • M.Wt:
  • Formula:
  • Solubility:
    Soluble to 25 mM in water
  • Purity:
  • Storage:
    Store at RT
  • CAS No:
The technical data provided above is for guidance only. For batch specific data refer to the Certificate of Analysis. All Tocris products are intended for laboratory research use only.
Background References
  1. Antinociceptive profile of 3-α-tropanyl-(2-Cl)-acid phenoxybutyrate (SM-21): a novel analgesic with a presynaptic cholinergic mechanism of action.
    Ghelardini et al.
    J.Pharmacol.Exp.Ther., 1997;282:430
  2. Pharmacological identification of SM-21, the novel σ2 antagonist.
    Ghelardini et al.
    Pharmacol.Biochem.Behav., 2000;67:659
  3. (±)-SM 21 attenuates the convulsive and locomotor stimulatory effects of cocaine in mice.
    Matsumoto and Mack
    Eur.J.Pharmacol., 2001;417:R1

The citations listed below are publications that use Tocris products. Selected citations for SM-21 maleate include:

2 Citations: Showing 1 - 2
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  1. Potentiation of nerve growth factor-induced neurite outgrowth in PC12 cells by ifenprodil: the role of σ-1 and IP3 receptors.
    Authors: Ishima and Hashimoto
    J Diabetes Res 2012;7:e37989
  2. Effects of UMB24 and (+/-)-SM 21, putative σ2-preferring antagonists, on behavioral toxic and stimulant effects of cocaine in mice.
    Authors: Matsumoto Et al.
    PLoS One 2007;86:86

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