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.

Objective:To investigate the psychological stress and related factors of community medical staff in Shanghai during infectious public health emergencies.Methods:Random cluster sampling, questionnaires combining general demographic information, self-rating anxiety scale(SAS), self-rating depression scale(SDS)and yale-brown obsessive compulsive scale(YB)were administrated to investigate the psychological stress of medical staff from 20 community healthcare centers in 10 Shanghai districts.Results:A total of 696 valid questionnaires were collected. 17.36% of the staff had SAS scores exceeding the boundary value. Nurses, staff with per capita monthly family income<5 000 yuan, or with below-average family relations presented higher SAS scores. 28.19% of the staff had SDS scores exceeding the boundary value. Staff with 5-10 years seniority, nurses, with per capita monthly family income<5 000 yuan, and with poor family relations presented higher SDS scores. 6.68% of the staff had YB score≥16. Nurses presented a higher YB score.Conclusions:Some community healthcare center staff experienced psychological stress during public health emergencies.Factors associated with psychological stress, such as 5-10 years′ seniority, nurses, per capita monthly family income<5 000 yuan, below-average or poor family relations, deserve more attention in order to prevent from or alleviate harmful psychological stress.