Lipski J, Waldvogel H J, Pilowsky P, Jiang C
Department of Physiology, School of Medicine, University of Auckland, New Zealand.
Brain Res. 1990 Oct 8;529(1-2):309-14. doi: 10.1016/0006-8993(90)90842-y.
Intracellular labelling with horseradish peroxidase (HRP) combined with gamma-aminobutyric (GABA) immunocytochemistry was used to assess the GABAergic input to inspiratory bulbospinal neurons of the dorsal respiratory group in the cat. The relationship between GABA-immunoreactive (GABA-IR) boutons and intracellularly labelled neurons was examined at the light microscopic and ultrastructural levels. At the light microscopic level, GABA-IR boutons were frequently found in close apposition to dendrites and cell bodies of labelled neurons. The presence of synapses was confirmed with electron microscopy. In addition, synaptic specializations were observed between immunoreactive boutons and unlabelled terminals which in turn formed synaptic contacts with HRP-labelled dendrites, a finding consistent with presynaptic inhibition. These results demonstrate a direct GABAergic input to a functionally defined population of medullary respiratory neurons, and suggest involvement of this neurotransmitter in the control of these neurons.
用辣根过氧化物酶（HRP）进行细胞内标记并结合γ-氨基丁酸（GABA）免疫细胞化学，以评估猫背侧呼吸组吸气性延髓脊髓神经元的GABA能输入。在光学显微镜和超微结构水平上检查了GABA免疫反应性（GABA-IR）终末与细胞内标记神经元之间的关系。在光学显微镜水平上，经常发现GABA-IR终末与标记神经元的树突和胞体紧密相邻。电子显微镜证实了突触的存在。此外，在免疫反应性终末与未标记的终末之间观察到突触特化，这些未标记的终末又与HRP标记的树突形成突触联系，这一发现与突触前抑制一致。这些结果证明了对功能明确的延髓呼吸神经元群体存在直接的GABA能输入，并提示这种神经递质参与了对这些神经元的控制。
