Roy G, Philippe E, Gaulin F, Guay G
Centre de Recherche en Neurobiologie, Université Laval, Hôpital de l'Enfant-Jésus, Québec, Canada.
Neuroscience. 1991;45(1):177-83. doi: 10.1016/0306-4522(91)90113-3.
The expression of gamma-aminobutyric acid was studied in sensory neurons and peripheral target tissues of the chick dorsal root ganglia by combining immunocytochemistry and electron microscopy. In the chick embryos, the first immunoreaction was observed at embryonic day 12 in 1.4% of ganglion cell bodies. The intensity of immunostaining gradually increased during development and the percentage of immunostained neurons reached an average of 7.3% after hatching. These immunostained cell bodies could be identified as sensory neurons belonging either to some large neurons of the A1 subclass or to a few small neurons of the B1 subclass. The other neuronal cell bodies, corresponding to the A2 and B2 subclasses, as well as the satellite and glial cells were apparently devoid of any gamma-aminobutyric acid immunostaining. Among the peripheral tissues innervated by the primary sensory neurons, the nerve endings of Achilles' tendon and the paravertebral autonomic ganglia appeared devoid of immunoreactivity. In contrast, immunoreactivity was found within nerve endings located in some neuromuscular spindles of the skeletal muscles and within some Herbst's corpuscles in the subcutaneous tissue of the skin. Thus, the present results provide evidence that gamma-aminobutyric acid may be expressed by neuronal cell bodies belonging to two subclasses of primary sensory neurons and could be a putative neurotransmitter involved in the peripheral sensory innervation of, at least in part, skin and skeletal muscles.
通过免疫细胞化学和电子显微镜相结合的方法，研究了雏鸡背根神经节感觉神经元和外周靶组织中γ-氨基丁酸的表达。在雏鸡胚胎中，在胚胎第12天观察到1.4%的神经节细胞体出现首次免疫反应。免疫染色强度在发育过程中逐渐增加，孵化后免疫染色神经元的百分比平均达到7.3%。这些免疫染色的细胞体可被鉴定为属于A1亚类的一些大型神经元或B1亚类的少数小型神经元的感觉神经元。对应于A2和B2亚类的其他神经元细胞体，以及卫星细胞和神经胶质细胞显然没有任何γ-氨基丁酸免疫染色。在初级感觉神经元支配的外周组织中，跟腱的神经末梢和椎旁自主神经节似乎没有免疫反应性。相反，在位于骨骼肌的一些神经肌梭内的神经末梢以及皮肤皮下组织的一些赫伯斯特小体中发现了免疫反应性。因此，目前的结果提供了证据，表明γ-氨基丁酸可能由属于初级感觉神经元两个亚类的神经元细胞体表达，并且可能是一种推定的神经递质，至少部分参与皮肤和骨骼肌的外周感觉神经支配。
