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Paper   IPM / Cognitive Sciences / 12864
School of Cognitive Sciences
  Title:   The time profile of morphine effect on different phases of Inhibitory avoidance memory in rat
  Author(s): 
1.  Mohammad Reza Zarrindast
2.  Abolfazl Ardjmand
3.  Ameneh Rezayof
4.  Shamseddin Ahmadi
  Status:   Published
  Journal: Archives of Iranian Medicine
  Vol.:  16
  Year:  2013
  Pages:   34-34
  Supported by:  IPM
  Abstract:
The amnesic effect of morphine is well known in the laboratory animals. But, it is unclear that morphine at what times can exactly affect different phases of memory, including acquisition, consolidation, and retrieval. Therefore, we investigated the time profle of morphine�??s amnesic effect on passive (inhibitory) avoidance learning and memory in male Wistar rats. Methods: In order to evaluate the outcomes of preand post-training administrations of morphine, the animals were trained in a stepthrough type of passive avoidance task at various time points, and were tested 24 h after training to measure memory retrieval. Results: The results showed that acquisition of memory was impaired in the animals that received a dose of 7.5 mg/kg of morphine (Intraperitoneally) at 0, 30 min, and 1 h before training, as evidenced by a decrease in step-through latency on the test day. Post-training administrations of morphine at 30 min and 1h, 4h except for the time immediately after training, did not impair memory consolidation. The results also showed that pre-test administrations of morphine at 0 and 30 min before the test, impaired retrieval of inhibitory avoidance memory. Conclusion: Taken together, the results suggest that morphine, when injected at different time points before training, after training, or before testing affects different phases of inhibitory avoidance memory. With regard to the time of injections related to each phase, other experiments can be designed to investigate molecular mechanisms involved in the impairing effect of morphine in each phase.

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