Effects of physostigmine and scopolamine on rats' performances in object-recognition and radial-maze tests.
The effects of physostigmine and scopolamine were evaluated on working memory of rats in object recognition and radial-maze tests. Three doses of physostigmine hemi-sulfate (Phys: 0.05, 0.10 and 0.20 mg/kg), five doses of scopolamine hydrobromide (Scop: 0.125, 0.25, 0.5, 1.0 and 2.0 mg/kg), and one dose of scopolamine methylbromide (Mscop: 2.0 mg/kg) were used. In object recognition test, rats were submitted to three or four intertrial delay conditions (1-min, 15-min and either 60-min or 24-h). The higher doses of Scop (1.0 and 2.0 mg/kg) in 1-min and 15-min delay and of Phys (0.20 mg/kg) in 1-min delay impaired discrimination between new and familiar objects. Mscop impaired discrimination between objects in 60-min but not in 1-min and 15-min delay. This effect may be state dependent. Radial-maze learning was impaired by the lower doses of scopolamine (0.25 and 0.50 mg/kg) which had no effect in object recognition test. These results show that in our conditions, object recognition is less sensitive than radial-maze test to cholinergic drugs.
Laboratoire de Psychophysiologie, Université Paris VII, France.
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Meliani
D000704:Analysis of Variance; D000818:Animals; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects*; D010830:Physostigmine / Q000494:pharmacology*; D011597:Psychomotor Performance / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012601:Scopolamine / Q000494:pharmacology*; D013997:Time Factors
D010830:Physostigmine; D012601:Scopolamine