Jonsson G, Fuxe K, Hökfelt T, Goldstein M
Med Biol. 1976 Dec;54(6):421-6.
The effects of the catecholamine neurotoxin 6-hydroxydopamine on phenylethanolamine-N-methyl transferase (PNMT) in rat brain has been investigated by biochemical and immunohistochemical analysis. 6-Hydroxydopamine was administerered either intracisternally to adult rats or systemically to newborn rats, treatments known to affect markedly central noradrenaline neurons. None of these treatments had any significant effect on the PNMT activity in the hypothalamus, pons-medulla and the spinal cord, as measured in vitro using a radiometric assay. The neonatal 6-hydroxydopamine treatment, which produced an almost complete noradrenaline denervation in the spinal cord, had no notable effect on the specific PNMT immunofluorescence localized in nerve terminals in the spinal cord. Transection of the spinal cord led to an almost complete disappearance of the PNMT activity and the specific immunofluorescence below the transection, pointing to the existence of a descending PNMT containing pathyway in the spinal cord. The present results show that the PNMT neurons are resistant to the neurotoxic action of 6-hydroxydopamine, possibly due to lack of catecholamine uptake mechanism or due to these neurons having an uptake mechanism with a low affinity for 6-OH-DA. Furthermore, the data support the view that the noradrenaline and PNMT containing neurons constitute separate neuron systems.
通过生化和免疫组织化学分析，研究了儿茶酚胺神经毒素6-羟基多巴胺对大鼠脑内苯乙醇胺-N-甲基转移酶（PNMT）的影响。将6-羟基多巴胺分别脑池内注射给成年大鼠或全身注射给新生大鼠，已知这些处理会显著影响中枢去甲肾上腺素能神经元。使用放射性测定法在体外测量时，这些处理均未对下丘脑、脑桥-延髓和脊髓中的PNMT活性产生任何显著影响。新生大鼠接受6-羟基多巴胺处理后，脊髓中几乎完全去甲肾上腺素能神经支配缺失，但对脊髓神经末梢中特异性PNMT免疫荧光没有显著影响。脊髓横断导致横断以下PNMT活性和特异性免疫荧光几乎完全消失，表明脊髓中存在一条下行的含PNMT通路。目前的结果表明，PNMT神经元对6-羟基多巴胺的神经毒性作用具有抗性，这可能是由于缺乏儿茶酚胺摄取机制，或者是由于这些神经元具有对6-OH-DA亲和力低的摄取机制。此外，数据支持去甲肾上腺素能神经元和含PNMT神经元构成独立神经元系统的观点。
