目的 研究甲状腺激素升高时脑纹状体多巴胺转运蛋白(DAT)、多巴胺(DA)及其代谢产物3,4二羟苯乙酸(DOPAC)的含量变化.方法 将24只大鼠分为2组,其中一组采用灌胃法连续每天给予大鼠左甲状腺素钠(优甲乐,用量按大鼠体质量25 ug100 g,溶于生理盐水中,体积1ml造成实验性大鼠甲状腺激素增高状态;对照组仅采用灌胃法给予生理盐水1 ml;于模型建立前后按随机数字表法抽取左甲状腺素钠组及对照组大鼠各6只,分别取尾静脉血1 ml,采用放射免疫法测定TT3及TT4水平.14 d后将上述对照组及左甲状腺素钠组大鼠再各自平均分为2组,一组用于99Tcm-2B-[N,N'一双(2-巯乙基)乙撑二胺基]甲基-3B-(4-氯苯基)托烷(TRODAT-1)大鼠脑内分布研究,另一组用于高效液相一电化学检测器(HPLC-ECD)测纹状体DA及DOPAC含量,观察上述大鼠脑纹状体区DAT的分布及DA、DOPAC含量的变化.多组比较采用ANOVA分析,2组间比较采用均数t检验.结果 左甲状腺素钠组大鼠在服用左甲状腺素钠后活动明显增加,体质量增长低于正常对照组[(223.90±8.40)与(261.60±14.20)g,t=6.98,P<0.05].甲状腺激素水平测定示:左甲状腺素钠组给药前后TT3分别为(1.46±0.17)和(2.72±O.29)nmol/L(t=10.51.P0.05),TT4分别为(98.38±9.77)和(88.38±6.76)mnel/L(t=1.36,P>0.05).99Tcm-TRODAT-I大鼠脑内分布(每克脑组织百分注射剂量率,%ID/g)研究示:左甲状腺素钠组纹状体为(2.80±O.25)%ID/g,明显低于正常对照组[(3.13±O.14)%ID/g,t=一3.62,P<0.05].经检测左甲状腺素钠组脑纹状体DA含量为(12 109.30±629.20),ng/g脑组织,明显高于对照组[(9012.CO±318.80)ng/g脑组织,t=10.76,P0.05 and(88.38±6.76) vs (98.38±9.77)nmol/L.t=1.36.P>O.05].For 99Tcm-TRODAT-l brain biodistribution(the percent injection dose of per gram of tissue,%ID/g),the striatum of thyroxin group was(2.80±0.25)%ID/g,lower than that of the control group [(3.13±0.14)%ID/g,t=-3.62,P<0.05].The content of striatum DA was(12 109.30±629.20)ng/g brain tissue,higher than that of the control[(9012.00±318.80)ng/g brain tissue,t=10.76.P<0.000l 1],the content of DOPAC Was(1079.3±97.00)ng/g brain tissue,higher than that of the control[(873.20±67.50)ng/g brain tissue,t=4.27.P<0.05].Conclusions Decreased 99Tcm-TRODAT-1 uptake was ob-served in striatum DAT during rats with experimental hyperthyroidism.The possible reason might be due to the increased dopamine binding with DAT.
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