Sashkov V A, Sel'verova N B, Morenkov É D, Ermakova I V
Zh Evol Biokhim Fiziol. 2010 Jul-Aug;46(4):304-10.
Sexual peculiarities of dynamics of brain sex steroids in the process of learning and extinction of the conditioned reflex of passive avoidance have been studied in model experiment. Prior to learning of conditioned reflex, females were found to be distinguished by manifestation of anxiety and fear as compared with males. At formation of the conditioned reflex, no significant sex differences were detected between males and females, whereas extinction of the conditioned reaction of passive avoidance in rat males occurred by 2-3 days faster than in females. At learning of conditioned reaction of passive avoidance, in sexually mature rat males there was revealed an increase of the testosterone content in various brain structures, especially in hippocampus and frontal cortex, while its level in blood plasma remained unchanged. Also shown was an elevation of estradiol concentration in female amygdale, whereas at extinction of the conditioned reaction of passive avoidance, a rise of estradiol values was noted in hippocampus and cingular cortex. At the same time the testosterone level in blood plasma did not change, whereas the estradiol concentration decreased statistically significantly after extinction of the conditioned reflex. Different dynamics of changes of the sex steroid levels in brain and blood plasma can indicate a probability of their formation in the nervous tissue. The performed correlation analysis confirms the concept of selective involvement of testosterone and estradiol of specific brain structures in realization of the process of learning and memory in sexually mature rat males and females.
在模型实验中，研究了被动回避条件反射学习和消退过程中大脑性类固醇动力学的性别特征。在条件反射学习之前，发现雌性与雄性相比表现出焦虑和恐惧。在条件反射形成时，未检测到雄性和雌性之间存在显著的性别差异，而大鼠雄性被动回避条件反应的消退比雌性快2至3天。在被动回避条件反应学习时，性成熟大鼠雄性的各种脑结构，尤其是海马体和额叶皮质中的睾酮含量增加，而其血浆水平保持不变。还发现雌性杏仁核中的雌二醇浓度升高，而在被动回避条件反应消退时，海马体和扣带回皮质中的雌二醇值升高。与此同时，血浆中的睾酮水平没有变化，而在条件反射消退后，雌二醇浓度在统计学上显著下降。大脑和血浆中性类固醇水平变化的不同动态可能表明它们在神经组织中形成的可能性。所进行的相关分析证实了特定脑结构中的睾酮和雌二醇选择性参与性成熟大鼠雄性和雌性学习和记忆过程的概念。
