David J C, Rush R A
J Neurochem. 1984 Dec;43(6):1527-31. doi: 10.1111/j.1471-4159.1984.tb06073.x.
The presence of the catecholamine synthetic enzyme, phenylethanolamine N-methyl transferase (PNMT), has been detected in the expansor secundariorum, a smooth muscle of the avian wing. The concentration of the enzyme was estimated over a 10-week time course from 17 days incubation to 9 weeks posthatch and found to increase rapidly up until hatch in parallel with dopamine beta-hydroxylase activity, but then to fall precipitously to very low levels. The time course of the initial increase in activity corresponds to the presence of ingrowing sympathetic nerve fibres, and denervation of the expansor results in loss of greater than 80% of the PNMT activity. It is concluded that during the period of innervation the growing nerves contain the enzyme PNMT and therefore have the capacity to synthesize adrenaline, but that shortly after innervation is complete the capacity to synthesize adrenaline is lost. Several alternate mechanisms are proposed to explain the observations.
在鸟类翅膀的平滑肌——次级扩张肌中已检测到儿茶酚胺合成酶苯乙醇胺N-甲基转移酶（PNMT）。在从孵化17天到孵化后9周的10周时间内对该酶的浓度进行了估算，发现该酶浓度在孵化前迅速上升，与多巴胺β-羟化酶活性平行，但随后急剧下降至非常低的水平。活性最初增加的时间进程与生长中的交感神经纤维的存在相对应，对扩张肌进行去神经支配会导致PNMT活性损失超过80%。得出的结论是，在神经支配期间，生长中的神经含有PNMT酶，因此有合成肾上腺素的能力，但在神经支配完成后不久，合成肾上腺素的能力就丧失了。提出了几种替代机制来解释这些观察结果。
