摘要
为探讨大鼠睪丸是否存在GABA样受体并了解它在不同发育时期的表达情况,本实验将大鼠睪丸的mRNA微注射进入爪蟾卵母细胞表达;电压钳记录结果显示:用500μmol/L浓度GABA溶液灌流可引发其产生约30nA的内向电流.表明大鼠睪丸可能存在GABA受体,用GABA_A 受体抑制剂Bicuculine和Picrotoxin可抑制GABA的这种作用.用GABA_A 受体激动剂Muscimol溶液灌流可引发内向电流产生,而用GABA_B受体激动剂Baclofen则无此效应,表明睪丸组织存在的GABA受体主要为A亚型而非B亚型.基于上述结果,本实验根据神经系GABA受体亚基多肽链第二跨膜区的.cDNA保守序列合成探针,用与成年大鼠脑和各生长发育时期大鼠睪丸RNA进行斑点(dot)杂交分析,结果显示成年大鼠睪丸比其大脑有较强的杂交信号,表明睪丸的受体RNA可能比脑组织GABA受体RNA与探针序列有较多的同源区段,提示该受体可能是一种类似于GABA的受体,即GABA_A样受体(GABA_A like receptor).同时,斑点杂交结果还进一步显示不同发育时期大鼠睪丸GABA_A样受体表达有差异,基本规律是新生大鼠表达量极少,出生30d至100d时表达量最高,200d后表达开始减少.
For making it clear whether GABA_A like receptor is in rat testis and how its gene expresses in tissue cells,mRNA of rat testis was microinjected into Xenopus oocyte and membrane electro-biological results showed that an inward 30 nA micro -currents were elicited under two - electrode voltage -clamped configuration,by extracellular GABA (500 μmol/L). However,both Bicu-culline and Picrotoxin can inhibit this effectiveness,indicating that GABA receptor can be the expressed in the membrane of Xenopus oocyte. Using Muscimol as a excitant of GABA receptor type A, also elicited the micro - currents were. Then using Baclofen as an excitant of GABA receptor type B could not induce the micro - currents. These results indicated that GABA receptor expressed in Xenopus oocyte membrane is not type B but type A. Following the research result above, 24 mer oligonucleotides to be complementary to the conservative region of the cDNA of neur -GABA receptor were synthesized,and were used as probes to hybrid respectively with the RNAs of brain and testes of the various developmental age of rats. The results of dot hybridization pointed out that the hybrid signal of rat testes was stronger than that of rat brain,meaning that,compared with rat brain,the RNA of rat testes had more homology with probes,and also implying that the GABA receptor from rat testis RNA could be different from,but similar to neur -GABA receptor. The dot blot analysis above showed the expressing regularity of GABA_A-like receptor gene in rat testes of various developing stages. There was a very low level of gene expression in the rat testis of day 5 postnatal while there was the highest expression of GABA_A -like receptor gene in rat testes of the birth from day 30 to 100,The expression begins to drop at day 200 after birth.
出处
《生殖与避孕》
CAS
CSCD
北大核心
1998年第3期136-140,共5页
Reproduction and Contraception
基金
美国洛氏基金
国家攀登计划
中国科学院上海细胞生物学研究所分子细胞生物学开放实验室资助项目
关键词
氨基丁酸
受体
基因
睾丸
基因表达
GABAA - like receptor, Gene expression, Rat testis mRNA,Xenopus oocyte, Voltage - clamp, Dot hybridization analysis
