Cholinergic mechanisms in the learning and memory facilitating effect of the central stimulants. III. Influence of the anticholinergic agents on the learning and memory facilitating effect of amphetamine.

In experiments involving training of albino rats in a maze it has been established that amphetamine in a dose of 0.5 mg/kg introduced 15 min before learning has almost no effect, in a dose of 2 mg/kg it slightly deteriorates learning and retention, while in a dose of 1 mg/kg both learning and retention are markedly improved. However, introduced immediately after training, all three doses tested improve retention upon testing 24 hours and 14 days after training. Upon blocking of the central muscarine-sensitive cholinergic structures (scopolamine 2 mg/kg) and of the nicotine-sensitive structures (spasmolytin 20 mg/kg), the learning and memory facilitating effect of amphetamine is not manifested in the two experimental setups (introduction before and after training). The results resemble the case of independent administration of cholinolytics only, i.e. complete blocking of learning and memory induced by scopolamine and considerable deterioration induced by spasmolytin. The results obtained show that the realization of the learning and retention facilitating effect of amphetamine requires optimum functional level of the activity of the central cholinergic system.