脑发育期甲状腺激素对大鼠听觉中潜伏期反应和学习记忆的影响  

Effects of thyroid hormone on auditory middle latency response and functions of learning and memory in developmental period of rat brain

作　　者：尹益勇[1] 刘妮[1] 李华娇[1] 何斯纯[1] 

机构地区：[1]暨南大学医学院生理学教研室,广东广州510632

出　　处：《暨南大学学报（自然科学与医学版）》2011年第2期165-170,共6页Journal of Jinan University(Natural Science & Medicine Edition)

基　　金：广东省中医药局建设中医药强省科研项目(2007124)

摘　　要：目的：探讨脑发育期甲状腺激素对大鼠听觉中潜伏期反应（MLR）和学习记忆的影响效应。方法：孕鼠从孕第1天至仔鼠生后30 d饮含质量浓度为0.3 g/L甲硫咪唑的自来水诱发甲状腺功能低下仔鼠,每天腹腔注射质量分数为0.02 mg/kg左旋甲状腺素（L-T4）进行替代治疗。分为H组（甲低）、RP1组（生后1-30 d替代治疗）、RP7组（生后7-30 d替代治疗）、RP14组（生后14-30 d替代治疗）、RP21组（生后21-30 d替代治疗）和N组（正常对照）。放射免疫法测定大鼠血清游离三碘甲腺原氨酸（FT3）和血清游离甲状腺素或四碘甲腺原氨酸（FT4）。计算机平均叠加技术颅表记录大鼠MLR。Morris水迷宫测定大鼠的学习记忆能力。结果：RP1组大鼠MLR引出时间正常,RP7和RP14组大鼠MLR延迟引出,RP21和H组大鼠MLR更晚引出。RP1、RP7、RP14和RP21组大鼠MLR延长的波峰潜伏期（PL）和波峰间潜伏（IPL）可明显改善,正常时间分别为生后20、26、29和39d,H组MLR的PL和IPL在生后60 d仍明显延长。生后60 d,RP1和RP7组大鼠水迷宫逃避潜伏期和游泳路程正常,但RP14和RP21组大鼠水迷宫逃避潜伏期和游泳路程明显延长,H组大鼠逃避潜伏期和游泳路程延长更为突出。结论：大鼠听觉功能和学习记忆功能发育依赖甲状腺激素的关键期有所不同,替代治疗越早,疗效越好。Aim：To study the effects of thyroid hormone on the auditory middle latency response（MLR） and functions of learning and memory in the developmental period of brain in the rats.Methods： The rat pups with congenital hypothyroidism were induced by methimazole solution of 0.3 g/L mass concentration added in the drinking water for their mothers from the pregnant day 1 to the postnatal day 30,and the injection of L-thyroxine（L-T4） of 0.02 mg/kg mass fraction into abdominal cavity in the related each day for replacing treatment.The rat pups were randomly divided into 6 groups,group H（hypothyroidism）,group RP1（replacing treatment from postnatalay 1 to 30）,group RP7（replacing treatment from postnatal day 7 to 30）,group RP14（replacing treatment from postnatal day 14 to 30）,group RP21（replacing treatment from postnatal day 21 to 30）,and group N（control）.Serum free triiodothyronine（FT3） and thyroxine or tetraiodothyronine（FT4） of the rats were determined by radioimmunoassay.MLR were recorded with the summation-average technique of computer from the skull surface of the rats.The functions of learning and memory of the rats were determined with Morris water maze.Results： MLR of the rats in group RP1 emerged normally.But MLR of the rats in group RP7 and RP14 emerged later,and MLR of the rats in group RP21 and H emerged further later.The prolonged peak latency（PL） and interpeak latency（IPL） of MLR in rats of group RP1,RP7,RP14 and RP21 could be corrected significantly,and became normal at postnatal day 20,26,29 and 39 respectively.But the PL and IPL of MLR in the rats of group H at postnatal day 60 were still prolonged significantly.The escaped latency and swimming path in the Morris water maze test in the rats of group RP1 and RP7 were normal at postnatal day 60.However,the escaped latency and swimming path were prolonged significantly in the rats of group RP14 and RP21,and more significantly prolonged in the rats of group H.Conclusion：The thyroid hormone-dependent critical

关 键 词：甲状腺激素 大鼠 听觉 中潜伏期反应 学习记忆 

分 类 号：R338[医药卫生—人体生理学]