Ghelardini et al (1997) Antinociceptive profile of 3-a-tropanyl-(2-Cl)-acid phenoxybutyrate (SM-21): a novel analgesic with a presynaptic cholinergic mechanism of action. J.Pharmacol.Exp.Ther. 282 430. Ghelardini et al (2000) Pharmacological identification of SM-21, the novel s2 antagonist. Pharmacol.Biochem.Behav. 67 659. Matsumoto and Mack (2001) (±)-SM 21 attenuates the convulsive and locomotor stimulatory effects of cocaine in mice. Eur.J.Pharmacol. 417 R1.