Val 70, Phe 72 and the last seven amino acid residues of C-terminal are essential to the function of norepinephrine transporter

The norepinephrine transporter(NET) is a member of the Na+/Cl- dependent neurotransmitter transporter family and constitutes the target of several clinically important antidepressants. To delineate the critical amino acid residues and the function of C-terminal in regulating transport activity of NET, here we constructed two site mutants (V70F, F72V; V70I, F72V) and one C-terminal truncated mutant (△611-617). The wild type and mutants of NET were expressed in Xenopus oocytes by injection of their cRNA. We found that all of these mutants lost their transport activity. These results indicate that the amino acid residues of V70 and F72 3 and the last seven amino acids of C-terminal are essential to the transport activity of NET.

胆碱乙酰基转移酶活性快速测定诊断臂丛损伤的实验研究

目的寻找一种简单快速、能在手术中准确客观地判断臂丛损伤神经残端功能的方法。方法选用成年雌性SD大鼠45只,随机分成两组,分别制成臂丛节前和节后损伤的动物模型,采用放射性同位素的方法测定损伤后不同时间臂丛神经中胆碱乙酰基转移酶(choline acetyltransferase,ChAT)的活性,然后用统计学的方法总结其中规律。结果节前、节后两种损伤类型胆碱乙酰基转移酶的活性均随时间降低,节前组ChAT活性随时间迅速降低,很快达到正常活性的1/10(675±258) cpm；节后组ChAT活性随时间缓慢降低,90 d后只降低到正常活性的1/2(4906±1119)cpm。结论术中快速测定ChAT的活性可以用来定量地区分臂丛损伤后的神经残端功能,以判定残端的可利用性。