ISSN:
1432-2072
Keywords:
Passive avoidance
;
Learning
;
Memory Scopolamine
;
Atropine
;
Diazepam
;
Lorazepam Rats
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Both muscarinic antagonists, such as scopolamine, and benzodiazepine receptor (BZR) agonists, such as diazepam, produce a reliable impairment in the performance of one trial passive avoidance. Such deficits are frequently interpreted as drug-induced amnesia. However, these deficits could also result from a learning impairment. The present experiments compared the effects of two BZR agonists, lorazepam (0, 0.125, 0.25, and 0.375 mg/kg, IP) and diazepam (0, 0.78, 1.56, and 3.13 mg/kg, IP) with the effects of two muscarinic antagonists, scopolamine (0, 0.6, 0.8 and 1.0 mg/kg, SC) and atropine (0, 15, 30 and 60 mg/kg, IP) on a multiple trial passive avoidance task. In this procedure, the rats were trained with a 5-min inter-trial interval until a learning criterion was achieved. Retention was assessed 24 h later. This enabled the effects of the drugs on the acquisition and the retention of a passive avoidance response to be dissociated. Both atropine and scopolamine produced a marked impairment in the acquisition of the passive avoidance response, but did not impair retention. In contrast, diazepam and lorazepam did not alter the acquisition of a passive avoidance response, but did produce a dose-dependent impairment of retention. These results therefore demonstrate a double dissociation between the effects of muscarinic antagonists and BZR agonists on the acquisition and retention of passive avoidance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02245247
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