皮质酮损害大鼠新颖物体识别记忆的再巩固

摘要

BACKGROUND: The formation of long-term memory includes acquisition, consolidation and reconsolidation. Reconsolidation is very important for the new memory transforming into stable memory. Stress is an important environmental factor in the process of learning and memory. Corticosterone is very important for stress response. At present, research about the impact of corticosterone on reconsolidation of novel object recognition memory is less. Thus, it is very important to test the impact of corticosterone on reconsolidation of novel object recognition memory in rats. OBJECTIVE: To analyze the effects of corticosterone on the reconsolidation of novel object recognition memory in rats. METHODS: (1) The rats were intraperitoneal y injected with corticosterone (0.1, 1 and 3 mg/kg) immediately after reactivation. The discrimination index was used to assess memory performance and calculated as the difference in time exploring the novel and familiar objects. (2) The rats were intraperitoneal y injected with corticosterone (3 mg/kg) 6 hours after reactivation. The discrimination index was used to assess memory performance and calculated as the difference in time exploring the novel and familiar objects. (3) The rats were intraperitoneal y injected with corticosterone 3 mg/kg without reactivation. The discrimination index was used to assess memory performance and calculated as the difference in time exploring the novel and familiar objects. RESULTS AND CONCLUSION: Immediate injection of corticosterone 3 mg/kg after reactivation significantly decreased the discrimination index. At 6 hours after reactivation or without reactivation, corticosterone administration did not impact the discrimination index. These results confirmed that corticosterone administration immediately after reactivation impairs the reconsolidation of novel object recognition memory. The damage effect depends on the reactivation experience and the specific time window after reactivation.%背景：长时程记忆形成通常包括获得、巩固、再巩固等多个环节，再巩固过程对于新获得的记忆转为稳定记忆十分重要。在学习记忆过程中，应激是一种重要的环境因素；而在应激过程中，皮质酮是发挥重要作用的一种激素。目前，关于皮质酮对新颖物体识别记忆再巩固的影响未见相关研究报道。因此检测皮质酮对大鼠新颖物体识别记忆再巩固过程的影响具有十分重要的意义。　　目的：分析皮质酮对大鼠新颖物体识别记忆再巩固的影响。　　方法：①大鼠在再激活后立即腹腔注射皮质酮(0.1，1及3 mg/kg)，以大鼠在测试阶段对新旧物体探究时间的辨别指数作为记忆评价指标；②再激活后6 h 腹腔注射皮质酮(3 mg/kg)，以大鼠在测试阶段对新旧物体探究时间的辨别指数作为记忆评价指标；③无再激活经历时腹腔注射皮质酮(3 mg/kg)，以大鼠在测试阶段对新旧物体探究时间的辨别指数作为记忆评价指标。　　结果与结论：再激活后立即注射皮质酮(3 mg/kg)显著性降低大鼠辨别指数，再激活后6 h 或无再激活经历时注射皮质酮对大鼠辨别指数无影响。提示再激活后立即注射皮质酮损害大鼠新颖物体识别记忆再巩固，该损害效应依赖于再激活经历及再激活后特定时间窗。