Edvinsson L, Aubineau P, Owman C, Sercombe R, Seylaz J
Stroke. 1975 Sep-Oct;6(5):525-30. doi: 10.1161/01.str.6.5.525.
The inactivation of the norepinephrine transmitter in the region of the adrenergic receptor is one important function of the sympathetic nerve terminals innervating blood vessels. This capacity was tested on isolated cat's middle cerebral artery (MCA) by recordings of the contractile response induced by norepinephrine at various stages after sympathectomy (excision of the superior cervical ganglion). Within three days after denervation, when fluorescence microscopy revealed a disappearance of neuronal norepinephrine in the vessel wall, there was a threefold increase in sensitivity of the test system which was not further enhanced at two weeks. This, and the finding of a similar amount of sensitization (of non-denervated vessels) to norepinephrine or tyramine after cocaine treatment, showed that a prejunctional type of sensitivity had developed. The sympathetic denervation did not influence the dose-response curve obtained with acetylcholine, supporting the specific nature of the supersensitivity reaction only to the sympathetic transmitter. Half a year after sympathectomy the sensitivity of the pial arteries to norepinephrine returned to control levels despite the absence of reinnervation, indicating that postjunctional changes also occurred. The findings offer further evidence for a functional role of the sympathetic nerves supplying intracranial arteries and show that the mode of innervation resembles that found in peripheral vessels.
去甲肾上腺素递质在肾上腺素能受体区域的失活是支配血管的交感神经末梢的一项重要功能。通过记录交感神经切除（切除颈上神经节）后不同阶段去甲肾上腺素诱导的猫大脑中动脉（MCA）的收缩反应，对这一功能进行了测试。去神经支配后三天内，当荧光显微镜显示血管壁内神经元去甲肾上腺素消失时，测试系统的敏感性增加了两倍，在两周时并未进一步增强。这一点，以及可卡因处理后（未去神经支配的血管）对去甲肾上腺素或酪胺出现相似程度的致敏现象，表明出现了一种节前型敏感性。交感神经去神经支配并不影响用乙酰胆碱获得的剂量-反应曲线，这支持了超敏反应仅对交感神经递质具有特异性的性质。交感神经切除半年后，尽管没有重新神经支配，软脑膜动脉对去甲肾上腺素的敏感性恢复到对照水平，这表明节后也发生了变化。这些发现为供应颅内动脉的交感神经的功能作用提供了进一步的证据，并表明其神经支配方式与外周血管相似。
