Lau Y S, Hao R, Fung Y K, Fu L S, Bishop J F, Pfeiffer R F, Mouradian M M
Division of Pharmacology, School of Pharmacy, University of Missouri-Kansas City, 64108, USA.
Neurochem Res. 1998 Apr;23(4):525-32. doi: 10.1023/a:1022482518292.
Brain-derived neurotrophic factor (BDNF) promotes the differentiation and growth of developing dopamine (DA) neurons and supports the survival of mature DA cells in culture. However, the neurotrophic role of endogenous BDNF in the adult DA system in vivo has not been well established. To investigate the hypothesis that blockade of endogenous BDNF expression results in DA dysregulation, we used an 18-mer antisense oligodeoxynucleotide (ODN) targeted to the first ATG codon of the BDNF transcript. The biological activity of the antisense ODN was initially tested in vitro. In cultured dopaminergic MES 23.5 cells, antisense BDNF (20 microM) effectively reduced BDNF protein expression and cell survival. Furthermore, in primary embryonic mesencephalic cultures, antisense BDNF reduced the number of tyrosine hydroxylase positive neurons and inhibited [3H]DA uptake in a time- and dose-dependent manner. The specificity of the antisense molecule was confirmed by comparing its effects with those of a control ODN having the same base composition but in scrambled sequence. In rats, two days following an intranigral or intrastriatal injection of antisense BDNF (0.5 microg), we observed a two-fold and five-fold increase in nigral DA levels, respectively, but no change in striatal DA content. Seven days after an intrastriatal antisense BDNF injection, DA levels were elevated in the striatum apparently due to decreased DA turnover. These observations suggest that inhibition of endogenous BDNF expression tends to augment rather than inhibit nigrostriatal DA transmission. Thus, the biological effects of endogenous BDNF on the nigrostriatal DA system in the adult organism merits further investigation.
脑源性神经营养因子（BDNF）可促进发育中的多巴胺（DA）神经元的分化和生长，并在培养中支持成熟DA细胞的存活。然而，内源性BDNF在成年体内DA系统中的神经营养作用尚未得到充分证实。为了研究内源性BDNF表达的阻断导致DA调节异常这一假说，我们使用了一种针对BDNF转录本第一个ATG密码子的18聚体反义寡脱氧核苷酸（ODN）。反义ODN的生物活性首先在体外进行了测试。在培养的多巴胺能MES 23.5细胞中，反义BDNF（20μM）有效地降低了BDNF蛋白表达和细胞存活率。此外，在原代胚胎中脑培养物中，反义BDNF以时间和剂量依赖的方式减少了酪氨酸羟化酶阳性神经元的数量并抑制了[3H]DA摄取。通过将其作用与具有相同碱基组成但序列混乱的对照ODN的作用进行比较，证实了反义分子的特异性。在大鼠中，黑质内或纹状体内注射反义BDNF（0.5μg）两天后，我们分别观察到黑质DA水平增加了两倍和五倍，但纹状体DA含量没有变化。纹状体内注射反义BDNF七天后，纹状体中的DA水平明显升高，这显然是由于DA周转率降低所致。这些观察结果表明，内源性BDNF表达的抑制倾向于增强而非抑制黑质纹状体DA传递。因此，内源性BDNF对成年生物体黑质纹状体DA系统的生物学作用值得进一步研究。
