A comparison of the effects of diazepam and scopolamine in two positively reinforced learning tasks.
In a helical maze scopolamine (0.5 and 1 mg/kg) significantly impaired the ability of rats to acquire a spatial learning task using reference memory. In contrast, diazepam (0.5-2 mg/kg) did not impair acquisition of this task and the only effect of diazepam (4 mg/kg) was likely to be secondary to sedative effects. Diazepam (0.5-4 mg/kg) did not impair 8-day retention of the helical maze. In a test of working and reference memory in which spatial processing was minimised, scopolamine (0.5 and 1 mg/kg) significantly impaired acquisition and increased the number of reference memory errors. Diazepam (1 and 4 mg/kg) did not impair acquisition of this task, but when a delay was interposed in the middle of a trial the diazepam-treated rats were slower to complete the task than the controls and made more errors of both working and reference memory. In contrast, when the rats were tested with a change of context, the diazepam-treated rats completed the task more quickly than the controls and made fewer errors of both working and reference memory.
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UMDS Division of Pharmacology, Guy's Hospital, London.
Mabbutt
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Toth
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D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D003975:Diazepam / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects; D051381:Rats; D012054:Reinforcement, Psychology; D012601:Scopolamine / Q000494:pharmacology*
D012601:Scopolamine; D003975:Diazepam