Effects of anisodine and other cholinergic drugs on learning and memory in spatial discrimination of mice

It has been recognized for a long time that some cholinergic drugs appear to affect the processes of information acquision, consolidation, maintenance and retrieval. Anisodine is a new muscarinic anticholinergic agent isolated from ScopoZia tangutica Maxim. It is similar to scopolamine both in chemical structure and in pharmacological properties. In this paper effects of anisodine. arecoline and hemicholinium on learning and memory were studied using spatial discrimination of mice as a model. Anisodine (l-5 mg/kg, ip) and hemicholinium (0.4-2.5 Ug. iv) inhibiting the physiological function of central cholinergic system impaired markedly the processes of acquisition. consolidation and retrieving of recent memory, while the remote memory remained unaffected. The role of anisodine on learning and memory appears to be specific and selective. Facilitation of acquisition was produced by arecoline 0.25-0.5 mg/kg (ip). but inhibition was obtained by 5-10 mg/kg. Arecoline 0.5 mg/kg effectively antagonized the disruptive effect of anisodine 5 mg/kg on acquisition process. The time span for consolidation of memory was <3 h in this model determined_by the administration of anisodine shortly after training. The result convincingly supports that normal function of the cholinergic system, especially the muscannic system is necessary for memory formation in mammalian brain. The modified spatial discrimination model may be useful for studying the pharmacology of learning and memory.