Kashefi Adel, Rashidy-Pour Ali
Laboratory of Learning and Memory, Research Center and Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran.
Laboratory of Learning and Memory, Research Center and Department of Physiology, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran.
Neurobiol Learn Mem. 2014 Oct;114:236-41. doi: 10.1016/j.nlm.2014.06.013. Epub 2014 Jul 9.
Previous studies have shown that post-training administration of glucocorticoids enhances memory consolidation in male rats, but theirs effects on female rats are not known. Thus, this study was conducted to examine the effects of corticosterone (CORT) on contextual fear memory consolidation in intact and ovariectomized (OVX) female rats. In Experiment 1, post-training administration of CORT (0.3, 3, and 10 mg/kg) to OVX female rats impaired memory consolidation at a 0.3 mg dose of CORT. In Experiment 2, post-training injection of CORT (0.3 mg/kg) to female rats in proestrus stage (when the levels of estrogens are highest) enhances and in the estrus stage (when the levels of estrogens are lowest) impaired memory retention. In Experiment 3, OVX female rats injected with CORT (0.3 mg/kg) and one of the three doses of 17β-estradiol (1, 10 or 100 μg/kg) following training. 48-h memory retention test indicated that CORT enhanced memory retention in OVX female rats that received concurrent injection of 10 or 100 μg doses of 17β-estradiol. These findings indicate that cognitive effects of CORT in female rats can be modulated with the plasma levels of estrogens: when the levels of estrogens are low, corticosterone has a negative effect, while when the levels of estrogens are high; the corticosterone has a positive enhancing effect.
先前的研究表明，训练后给予糖皮质激素可增强雄性大鼠的记忆巩固，但它们对雌性大鼠的影响尚不清楚。因此，本研究旨在探讨皮质酮（CORT）对完整和去卵巢（OVX）雌性大鼠情境恐惧记忆巩固的影响。在实验1中，对OVX雌性大鼠训练后给予CORT（0.3、3和10mg/kg），0.3mg/kg剂量的CORT损害了记忆巩固。在实验2中，对处于动情前期（雌激素水平最高时）的雌性大鼠训练后注射CORT（0.3mg/kg）可增强记忆，而在发情期（雌激素水平最低时）则损害记忆保持。在实验3中，训练后对OVX雌性大鼠注射CORT（0.3mg/kg）和三种剂量之一的17β-雌二醇（1、10或100μg/kg）。48小时记忆保持测试表明，CORT增强了同时注射10或100μg剂量17β-雌二醇的OVX雌性大鼠的记忆保持。这些发现表明，CORT对雌性大鼠的认知作用可随雌激素血浆水平而调节：当雌激素水平低时，皮质酮有负面影响，而当雌激素水平高时，皮质酮有积极的增强作用。
