Bowenkamp K E, Hoffman A F, Gerhardt G A, Henry M A, Biddle P T, Hoffer B J, Granholm A C
Department of Pharmacology, School of Dentistry, University of Colorado Health Sciences Center, Denver 80262, USA.
J Comp Neurol. 1995 May 15;355(4):479-89. doi: 10.1002/cne.903550402.
Glial cell-lined derived neurotrophic factor (GDNF) has been shown to promote survival of developing mesencephalic dopaminergic neurons in vitro. In order to determine if there is a positive effect of GDNF on injured adult midbrain dopaminergic neurons in situ, we have carried out experiments in which a single dose of GDNF was injected into the substantia nigra following a unilateral lesion of the nigrostriatal system. Rats were unilaterally lesioned by a single stereotaxic injection of 6-hydroxydopamine (6-OHDA; 9 micrograms/4 microliters normal saline with 0.02% ascorbate) into the medial forebrain bundle and tested weekly for apomorphine-induced (0.05 mg/kg s.c.) contralateral rotation behavior. Rats that manifested > 300 turns/hour received a nigral injection of 100 micrograms GDNF, or cytochrome C as a control, 4 weeks following the 6-OHDA lesion. Rotation behavior was quantified weekly for 5 weeks after GDNF. Rats were subsequently anesthetized, transcardially perfused, and processed for tyrosine hydroxylase immunohistochemistry. It was found that 100 micrograms GDNF decreased apomorphine-induced rotational behavior by more than 85%. Immunohistochemical studies revealed that tyrosine hydroxylase immunoreactivity was equally reduced in the striatum ipsilateral to the lesion in both cytochrome C and GDNF-injected animals. In contrast, large increments in tyrosine hydroxylase immunoreactivity were observed in the substantia nigra of animals treated with 100 micrograms of GDNF, with a significant increase in numbers of tyrosine hydroxylase-immunoreactive cell bodies and neurites as well as a small increase in the cell body area of these neurons. The results suggest that GDNF can maintain the dopaminergic neuronal phenotype in a number of nigral neurons following a unilateral nigrostriatal lesion in the rat.
胶质细胞源性神经营养因子（GDNF）已被证明在体外可促进发育中的中脑多巴胺能神经元的存活。为了确定GDNF对成年中脑损伤的原位多巴胺能神经元是否有积极作用，我们进行了实验，在黑质纹状体系统单侧损伤后，将单剂量的GDNF注入黑质。通过向内侧前脑束单次立体定位注射6-羟基多巴胺（6-OHDA；9微克/4微升含0.02%抗坏血酸的生理盐水）使大鼠单侧损伤，并每周检测阿扑吗啡诱导（0.05毫克/千克皮下注射）的对侧旋转行为。在6-OHDA损伤后4周，表现出>300转/小时的大鼠接受黑质注射100微克GDNF或细胞色素C作为对照。在注射GDNF后5周每周对旋转行为进行定量。随后将大鼠麻醉，经心脏灌注，并进行酪氨酸羟化酶免疫组织化学处理。发现100微克GDNF使阿扑吗啡诱导的旋转行为减少了85%以上。免疫组织化学研究表明，在注射细胞色素C和GDNF的动物中，损伤同侧纹状体中的酪氨酸羟化酶免疫反应性均同等程度降低。相比之下，在用100微克GDNF处理的动物的黑质中观察到酪氨酸羟化酶免疫反应性大幅增加，酪氨酸羟化酶免疫反应性细胞体和神经突数量显著增加，并且这些神经元的细胞体面积略有增加。结果表明，GDNF可以在大鼠单侧黑质纹状体损伤后维持许多黑质神经元中的多巴胺能神经元表型。
