Amiri Somayeh, Jafarian Zahra, Vafaei Abbas Ali, Motaghed-Larijani Zahra, Samaei Seyed Afshin, Rashidy-Pour Ali
Laboratory of Learning and Memory, Physiology Research Center, Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran.
Behvarzi Training Center, Semnan Health Center, Semnan University of Medical Sciences, Semnan, Iran.
Basic Clin Neurosci. 2015 Jul;6(3):155-62.
Recent studies suggest that glucocorticoids modulate memory reconsolidation. Moreover, cholinergic system is involved in memory reconsolidation. Since glucocorticoids interact with brain cholinergic system in modulating memory processing, we investigated whether glucocorticoid influences on the reconsolidation of emotionally arousing training depend on the cholinergic system.
Mice were trained (1mA, 3s footshock) in an inhibitory avoidance task. Forty-eight hours after training, memory reactivation was occurred (Test 1), and different treatments were given. Two (Test 2), five (Test 3), and seven days (Test 4) after memory reactivation (Test 1), animals were retested for fear memory retention.
In the first experiment, we observed that administration of corticosterone (CORT, 0.3, 1 and 3 mg/kg) following memory reactivation impaired subsequent expression of memory in a dose-dependent manner. In the second experiment, we found that CORT-induced impairment of memory reconsolidation was reversed by the muscarinic receptor antagonist atropine (0.5 and 2 mg/kg). In the third experiment, the nicotinic receptor antagonist mecaylamine (0.5 or 2 mg/kg) was not able to block the corticosterone response.
These findings indicate that glucocorticoids impair memory reconsolidation by a muscarinic cholinergic mechanism.
近期研究表明，糖皮质激素可调节记忆再巩固。此外，胆碱能系统也参与记忆再巩固过程。鉴于糖皮质激素在调节记忆过程中与脑胆碱能系统相互作用，我们研究了糖皮质激素对情绪唤起训练记忆再巩固的影响是否依赖于胆碱能系统。
小鼠在抑制性回避任务中接受训练（1毫安，3秒足底电击）。训练48小时后，进行记忆激活（测试1），并给予不同处理。在记忆激活（测试1）后的2天（测试2）、5天（测试3）和7天（测试4），对动物进行恐惧记忆保持的重新测试。
在第一个实验中，我们观察到记忆激活后给予皮质酮（CORT，0.3、1和3毫克/千克）会以剂量依赖的方式损害后续记忆表达。在第二个实验中，我们发现毒蕈碱受体拮抗剂阿托品（0.5和2毫克/千克）可逆转CORT诱导的记忆再巩固损伤。在第三个实验中，烟碱受体拮抗剂美加明（0.5或2毫克/千克）无法阻断皮质酮反应。
这些发现表明，糖皮质激素通过毒蕈碱胆碱能机制损害记忆再巩固。
