Jones B E, Holmes C J, Rodriguez-Veiga E, Mainville L
Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Quebec, Canada.
J Comp Neurol. 1991 Nov 8;313(2):349-67. doi: 10.1002/cne.903130210.
GABA-synthesizing neurons were identified in the medulla of the rat by peroxidase-antiperoxidase (PAP) immunohistochemistry for glutamic acid decarboxylase (GAD). Using diaminobenzidine (DAB) either alone or intensified with silver, a relatively large number of GAD-immunoreactive neurons were evident within the reticular formation, raphe nuclei and vestibular nuclei. In all these areas, profuse GAD-immunoreactive varicosities appeared to contact the soma and dendrites of both non-GABA and GABA neurons. These observations suggest that GABA neurons may act as interneurons or local projection neurons within the medulla and accordingly exert a potent inhibitory and/or disinhibitory control on bulbar projection neurons. Within the ventral reticular formation (pars alpha and ventralis of the gigantocellular reticular field) and raphe magnus, large numbers of prominent GAD-immunoreactive neurons resembled in size and morphology and overlapped in distribution the serotonin-immunoreactive neurons of the same regions. However, by sequential double immunostaining utilizing DAB as a chromogen for serotonin (5-HT) and benzidine dihydrochloride (BDHC) for GAD, it was found that GAD-containing neurons were distinct from 5-HT-containing neurons. Following injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the upper cervical spinal cord and combined processing for WGA-HRP (using tetramethylbenzidine [TMB] with cobalt) and immunohistochemistry (with DAB), a contingent of spinally projecting neurons were found to contain GAD. The GAD-immunoreactive reticulo- and raphe-spinal neurons were most frequent within the pars alpha and ventralis of the gigantocellular reticular fields and the raphe magnus, where they were approximately equal in number to the coexistent, but distinct 5-HT spinally projecting neurons. GABA neurons of the medulla may thus contribute directly to the bulbar inhibitory influence upon spinal sensory and motor systems.
通过针对谷氨酸脱羧酶（GAD）的过氧化物酶 - 抗过氧化物酶（PAP）免疫组织化学方法，在大鼠延髓中鉴定出了GABA合成神经元。单独使用二氨基联苯胺（DAB）或用银强化后，在网状结构、中缝核和前庭核内可见相对大量的GAD免疫反应性神经元。在所有这些区域，丰富的GAD免疫反应性曲张体似乎与非GABA和GABA神经元的胞体及树突相接触。这些观察结果表明，GABA神经元可能在延髓内充当中间神经元或局部投射神经元，并因此对延髓投射神经元施加有力的抑制和/或去抑制控制。在腹侧网状结构（巨细胞网状场的α部和腹侧部）和中缝大核内，大量显著的GAD免疫反应性神经元在大小和形态上相似，且在分布上与同一区域的5 - 羟色胺免疫反应性神经元重叠。然而，通过使用DAB作为5 - 羟色胺（5 - HT）的显色剂和二盐酸联苯胺（BDHC）作为GAD的显色剂进行连续双重免疫染色，发现含GAD的神经元与含5 - HT的神经元不同。将与辣根过氧化物酶（WGA - HRP）偶联的小麦胚凝集素注入颈上脊髓，并对WGA - HRP进行联合处理（使用四甲基联苯胺[TMB]加钴）和免疫组织化学（使用DAB）后，发现一群脊髓投射神经元含有GAD。GAD免疫反应性网状脊髓和中缝脊髓神经元在巨细胞网状场的α部和腹侧部以及中缝大核内最为常见，在这些部位它们的数量与共存但不同的5 - HT脊髓投射神经元大致相等。延髓的GABA神经元因此可能直接对延髓对脊髓感觉和运动系统的抑制影响做出贡献。
