Mohaddes Gisou, Naghdi Nasser, Khamnei Saeed, Khatami Shohreh, Haeri Ali
Dept. of Physiology and Pharmacology, Pasteur Institute of Iran, Tehran, Iran.
Applied Drug Research Centre of Tabriz University of Medical Sciences, Tabriz, Iran.
Iran Biomed J. 2009 Jan;13(1):49-58.
Sex steroids and their receptors exist in hippocampus and affect spatial learning and memory. This study was designed to measure testosterone level of CA1 and to assess the effect of spatial learning on its amount in left and right hippocampus of adult male rats.
Sixteen rats were divided into two intact and castrated groups, and then trained in Morris water maze (MWM). Another 40 animals were divided into four groups and their right or left hippocampus cannulated. Half of the animals in each group were castrated simultaneously. All the animals were trained in MWM. Microdialysis was performed and steroid contents of hippocampal dialysate were analyzed through HPLC/ultraviolet detection device method.
Results showed no significant differences between control and castrated animals in spatial learning after four days of training. Gonadectomy did not change testosterone level in CA1 region of hippocampus. Spatial learning decreased testosterone levels in CA1 region of hippocampus in right hippocampus of the non-castrated group. Significant differences were indicated in testosterone level between left and right hippocampus, in favor of left side in all groups.
Castration does not affect learning. Testosterone, as a neuromodulator, exists in CA1 region of hippocampus and training can decrease its level only in right hippocampus significantly. Lesser testosterone content of right hippocampus may show the conversion of it to other metabolites.
性类固醇及其受体存在于海马体中，并影响空间学习和记忆。本研究旨在测量成年雄性大鼠海马体CA1区的睾酮水平，并评估空间学习对其左右海马体中睾酮含量的影响。
将16只大鼠分为完整组和去势组，然后在莫里斯水迷宫（MWM）中进行训练。另外40只动物分为四组，对其右侧或左侧海马体进行插管。每组中的一半动物同时进行去势。所有动物均在MWM中接受训练。进行微透析，并通过高效液相色谱/紫外检测装置法分析海马体透析液中的类固醇含量。
结果显示，训练四天后，对照组和去势组动物在空间学习方面无显著差异。去势并未改变海马体CA1区的睾酮水平。空间学习降低了未去势组右侧海马体CA1区的睾酮水平。左右海马体的睾酮水平存在显著差异，所有组均以左侧为高。
去势不影响学习。睾酮作为一种神经调节剂，存在于海马体CA1区，且训练仅能显著降低右侧海马体中的睾酮水平。右侧海马体中较低的睾酮含量可能表明其已转化为其他代谢产物。
