Pu Ai Medical School, Shaoyang University, Shaoyang 422000, P.R. China.
Anesthesiology department, The Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang 421000, P.R. China.
Physiol Behav. 2023 Jul 1;266:114201. doi: 10.1016/j.physbeh.2023.114201. Epub 2023 Apr 16.
Trans-urocanic acid (UCA), an isomer of cis-UCA that is mainly located in the skin, has recently been reported to have a role in short-term working memory and in the consolidation, reconsolidation and retrieval of long-term memory. However, its effect on memory acquisition remains unclear. In the present study, the effect of UCA on short-term and long-term memory acquisition in mice was investigated using novel object recognition (NOR) and object location recognition (OLR) protocols that each involved three stages: habituation, sampling and testing. UCA was intraperitoneally injected 0.5 h pre-sampling, and the discrimination index during subsequent testing was determined in NOR and OLR tasks. The results showed that 10 mg/kg UCA significantly facilitated short-term and long-term memory acquisition in both types of tasks. Furthermore, 30 mg/kg UCA significantly facilitated long-term memory acquisition in the NOR task and tended to facilitate long-term memory acquisition in the OLR tasks but did not facilitate short-term memory acquisition in either task. Additionally, the enhancing role of UCA on memory acquisition was not dependent on changes of nonspecific responses, e.g. exploratory behavior and locomotor activity. The current study suggests that UCA facilitates short-term and long-term recognition memory acquisition, which further extends the functional role of UCA in the brain function.
反式尿刊酸（UCA）是顺式 UCA 的一种异构体，主要存在于皮肤中，最近有报道称其在短期工作记忆以及长期记忆的巩固、再巩固和检索中发挥作用。然而，其对记忆获取的影响尚不清楚。在本研究中，我们使用新物体识别（NOR）和物体位置识别（OLR）协议研究了 UCA 对小鼠短期和长期记忆获取的影响，这两个协议都包括三个阶段：习惯化、采样和测试。UCA 在采样前 0.5 小时腹腔注射，在 NOR 和 OLR 任务中确定随后测试期间的辨别指数。结果表明，10mg/kg 的 UCA 显著促进了两种任务的短期和长期记忆获取。此外，30mg/kg 的 UCA 显著促进了 NOR 任务中的长期记忆获取，并且倾向于促进 OLR 任务中的长期记忆获取，但在两种任务中均未促进短期记忆获取。此外，UCA 对记忆获取的增强作用不依赖于非特异性反应（例如探索行为和运动活性）的变化。本研究表明，UCA 促进了短期和长期识别记忆的获取，进一步扩展了 UCA 在大脑功能中的功能作用。
