The role of a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type receptor modulators in object recognition memory reconsolidation.

OBJECTIVE: Numerous studies suggest that the a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type (AMPA) receptor appears to play a central role in mediating brain functions, such as learning and memory. Trafficking of this receptor is related to different long-term memory processes. This study explores the role of two AMPA receptor (AMPAR) modulators in object recognition memory (ORM) reconsolidation. METHODS: First, the effects of immediate administration of each drug after memory reactivation were investigated and compared. Then, this drug's efficient time window and its effects without memory reactivation were investigated. RESULTS: Immediate CX546 administration after reactivation did not affect ORM reconsolidation. In contrast, administration of 10-mg/kg NBQX significantly impaired ORM reconsolidation within a 6-h time window. Importantly, the observed effects were not attributed to the exploratory behavior or locomotor activity of mice. CONCLUSION: These findings provide new evidence that the AMPA receptor plays an important role in the reconsolidation phase of ORM.

Urocanic acid enhances memory consolidation and reconsolidation in novel object recognition task.

Urocanic acid (UCA) is an endogenous small molecule that is elevated in skin, blood and brain after sunlight exposure, mainly playing roles in the periphery systems. Few studies have investigated the role of UCA in the central nervous system. In particular, its role in memory consolidation and reconsolidation is still unclear. In the present study, we investigated the effect of intraperitoneal injection of UCA on memory consolidation and reconsolidation in a novel object recognition memory (ORM) task. In the consolidation version of the ORM task, the protocol involved three phases: habituation, sampling and test. UCA injection immediately after the sampling period enhanced ORM memory performance; UCA injection 6 h after sampling did not affect ORM memory performance. In the reconsolidation version of the ORM task, the protocol involved three phases: sampling, reactivation and test. UCA injection immediately after reactivation enhanced ORM memory performance; UCA injection 6 h after reactivation did not affect ORM memory performance; UCA injection 24 h after sampling without reactivation did not affect ORM memory performance. This UCA-enhanced memory performance was not due to its effects on nonspecific responses such as locomotor activity and exploratory behavior. The results suggest that UCA injection enhances consolidation and reconsolidation of an ORM task, which further extends previous research on UCA effects on learning and memory.