Arai R, Horiike K, Hasegawa Y
Department of Anatomy, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.
Neurosci Lett. 1998 Jun 26;250(1):41-4. doi: 10.1016/s0304-3940(98)00429-7.
Dopamine-degrading activity of monoamine oxidase (MAO) was detected in the rat using a new histochemical method, with dopamine as the substrate. Our new method, designed to minimise the non-enzymatic oxidation of dopamine, was applied in combination with tyrosine hydroxylase (TH) and serotonin immunohistochemistry. We showed that the distribution pattern of MAO neurons was similar to that of TH-immunoreactive neurons (i.e. noradrenergic neurons) in the locus coeruleus (LC) and to that of serotonergic neurons in the dorsal raphe nucleus (DR). Since LC neurons form dopamine during noradrenaline biosynthesis, and DR neurons produce dopamine from exogenously administered L-dopa, our results indicate that dopamine produced in LC and DR neurons may be degraded, at least in part, by MAO.
采用一种新的组织化学方法，以多巴胺为底物，在大鼠体内检测了单胺氧化酶（MAO）的多巴胺降解活性。我们设计的这种新方法旨在尽量减少多巴胺的非酶促氧化，并将其与酪氨酸羟化酶（TH）和5-羟色胺免疫组织化学相结合应用。我们发现，MAO神经元的分布模式与蓝斑（LC）中TH免疫反应性神经元（即去甲肾上腺素能神经元）以及中缝背核（DR）中5-羟色胺能神经元的分布模式相似。由于LC神经元在去甲肾上腺素生物合成过程中会生成多巴胺，而DR神经元可从外源性给予的左旋多巴产生多巴胺，我们的结果表明，LC和DR神经元中产生的多巴胺可能至少部分会被MAO降解。
