Seiger A, Granholm A C
Cell Tissue Res. 1981;220(1):1-15. doi: 10.1007/BF00209961.
Surgical thyroidectomies were used as means of altering the thyroid state of adult recipients to study the possible influence of thyroid hormones on fibre formation in irides by immature noradrenaline neurons of the locus coeruleus grafted to the eye. Whole-mount preparations of irides were analysed using fluorescence histochemistry according to Falck-Hillarp, subjectively estimating on a 'blind' basis the number of fibres, their pattern of distribution and individual morphology in the iris dilator plate. Neurones of the locus coeruleus formed nerve fibres in irides of thyroidectomized recipients to the same extent as in controls. Distribution and fine structure of these fibres, however, differed markedly. The numerous thick axon bundles from the attachment of the brain graft, normally seen to radiate out from locus coeruleus-neurones in oculo, were almost totally lacking in the thyroidectomized group. Also, the individual nerve fibres showed abundant peripheral accumulations of fluorescent material. This appearance of the outgrowth of fluorescent fibres in the experimental group, indicative of a disturbed formation of nerve fibres during development in oculo, was abolished by reversal of the thyroid hormone deficiency using daily injections of l-thyroxin to the recipients throughout the experiment. This strongly indicates a role for thyroxin in the process of formation of nerve fibres originating from the neurones of the locus coeruleus during perinatal development. The present paper is supportive of recent reports claiming that during the development of the CNS thyroxin plays a crucial role in tubulin assembly, and thus presumably for the ability of neurones to form processes.
手术甲状腺切除术被用作改变成年受体甲状腺状态的手段，以研究甲状腺激素对移植到眼中的蓝斑未成熟去甲肾上腺素能神经元在虹膜中纤维形成的可能影响。根据法尔克-希拉尔普方法，使用荧光组织化学分析虹膜的整装标本，在“盲法”基础上主观估计虹膜开大肌板中纤维的数量、分布模式和个体形态。蓝斑神经元在甲状腺切除受体的虹膜中形成神经纤维的程度与对照组相同。然而，这些纤维的分布和精细结构明显不同。在甲状腺切除组中，通常可见从脑移植附着处发出的许多粗大轴突束，这些轴突束在眼中通常从蓝斑神经元呈放射状发出，但几乎完全缺乏。此外，单个神经纤维显示出荧光物质丰富的外周聚集。实验组荧光纤维生长的这种表现，表明在眼内发育过程中神经纤维形成受到干扰，通过在整个实验过程中每天给受体注射左旋甲状腺素纠正甲状腺激素缺乏后，这种表现消失了。这有力地表明甲状腺素在围产期发育过程中源自蓝斑神经元的神经纤维形成过程中起作用。本文支持最近的报道，即中枢神经系统发育过程中甲状腺素在微管蛋白组装中起关键作用，因此可能对神经元形成突起的能力也起关键作用。
