3-ALFA-TROPANYL 2-(4-Cl-PHENOXY)BUTIRATE (SM21): A REVIEW OF THE PHARMACOLOGICAL PROFILE OF A NOVEL ENHANCER OF CHOLINERGIC TRANSMISSION.

SM 21 is a 2-phenylpropionic acid ester, structurally related to atropine, that produces a central antinociceptive and antiamnesic effect in mice and rats. These activities are exerted without impairing motor coordination and without producing typical cholinergic symptomatology. SM 2 1 is also able to amplify the evoked contractions of smooth and striated muscle. A potentiation of endogenous cholinergic activity, by enhancing ACh extracellular levels, can be considered responsible for the action of SM 21 on both the central and peripheral nervous system. However, at this point the exact mechanism by which ACh levels are increased is not entirely elucidated.