学习记忆的分子神经机制（徐林）知识库

OBJECTIVE: To investigate whether repeated morphine exposure or prolonged withdrawal could influence operant and spatial learning differentially.

METHODS: Animals were chronically treated with morphine or subjected to morphine withdrawal. Then, they were subjected to two kinds of learning: operant conditioning and spatial learning.

RESULTS: The acquisition of both simple appetitive and cued operant learning was impaired after repeated morphine treatment. Withdrawal for 5 weeks alleviated the impairments. Single morphine exposure disrupted the retrieval of operant memory but had no effect on rats after 5-week withdrawal. Contrarily, neither chronic morphine exposure nor 5-week withdrawal influenced spatial learning task of the Morris water maze. Nevertheless, the retrieval of spatial memory was impaired by repeated morphine exposure but not by 5-week withdrawal.

CONCLUSION: These observations suggest that repeated morphine exposure can influence different types of learning at different aspects, implicating that the formation of opiate addiction may usurp memory mechanisms differentially.