Comparison of the inhibitory efficacy of four belladonna drugs on gastrointestinal movement and cognitive function in food-deprived mice

Belladonna drugs, scopolamine (Sco), atropine (Atr), anisodine (AT 3), and anisodamine (Ani), frequently used for gastrointestinal motility disorders often produce adverse effects on the central nervous system. In the present work, these drugs (0.05, 0.5, 5, and 50 μmol kg -1, i.p.) were evaluated for their potential to inhibit gastrointestinal motility and cognition in mice. Results showed that the maximum inhibitory rates of Sco, Atr, AT 3, and Ani on gastric emptying and small intestinal movement were 29.78, 40.69, 12.30, and 17.99% and 51.98, 58.46, 46.51, and 46.22%, respectively. The affinities of Sco, Atr, AT 3, and Ani for muscarinic receptors in the whole mice were 1.62, 1.48, 2.28, and 1.11 μmol kg -1 for the stomach or 0.30, 1.12, 0.59, and 1.14 μmol kg -1 for the small intestine, respectively. The minimal effective doses for impairing avoidance-response learning were 5 mu;mol kg -1 for Sco, Atr, or AT 3 and 50 μmol kg -1 for Ani. The initial doses for insulting the avoidance-response memory or open-field memory were 0.5, 5, 5, and 50 μmol kg -1 or 5, 5, 5, and >50 μmol kg -1 for Sco, Atr, AT 3, and Ani, respectively. We conclude that the relative susceptibility of the mouse's tissue or function capacities towards the inhibitory effects of belladonna drugs is small intestine > stomach > avoidance-response memory > avoidance-response learning > open-field memory.