An alkaloid with diverse biological activities; an antagonist of mAChRs (Kis = 0.19, 1.41, and 0.18 nM for the rat M1, M2, and M3 receptors, respectively); reduces acetylcholine-induced contractions in isolated guinea pig ileum (IC50 = 8.1 nM); inhibits oxotremorine-induced tremors in mice (ED50 = 0.23 mg/kg); increases fine motor activity counts and ambulatory activity in rats in a home-cage activity test (ED50 = 0.12 mg/kg for both); has been used to induce learning deficiencies or amnesia in animal models