Nagayama T, Namba H, Aonuma H
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan.
J Comp Neurol. 1997 Dec 8;389(1):139-48. doi: 10.1002/(sici)1096-9861(19971208)389:1<139::aid-cne10>3.0.co;2-g.
The inhibitory neurotransmitter of premotor nonspiking local interneurones in the crayfish terminal abdominal ganglion was investigated physiologically and immunocytochemically. Depolarization of a nonspiking interneurone evoked a hyperpolarization in a uropod motor neurone. The amplitude of hyperpolarization in the motor neurone was gradually decreased under low-calcium/high-magnesium saline. Local pressure injection of gamma-aminobutyric acid (GABA) into the neuropil caused a similar hyperpolarization of the motor neurone. These physiological studies suggested a GABAergic inhibitory interaction between nonspiking interneurones and the motor neurones. Premotor nonspiking interneurones are classified into two subgroups ofposterolateral (PL) and anterolateral (AL) interneurones, and AL interneurones are further divided into three subtypes. A combination of intracellular staining from nonspiking local interneurones with Lucifer yellow and immunocytochemical staining with an antiserum directed against GABA revealed that all the PL interneurones sampled in this study showed GABA-like immunoreactivity. A population of cell bodies (n = 6-11) with a small diameter (15-30 microm) packed together forming a cluster showed GABA-like immunoreactivity, and the cell bodies of most PL interneurones were found in this cluster. To compare the number and the pattern of main branches of PL interneurones, cells were classified into three identifiable sets of interneurones, called PL-1, PL-2, and PL-3. By contrast, about one-half of AL interneurones, especially the third subtype of AL interneurones, which have cell bodies located ventrolaterally in the ganglion, did not show GABA-like immunoreactivity. Furthermore, the position of cell bodies of GABA-immunoreactive AL interneurones was scattered compared to that of PL interneurones.
对小龙虾末节腹神经节中运动前非锋电位局部中间神经元的抑制性神经递质进行了生理学和免疫细胞化学研究。非锋电位中间神经元的去极化在尾足运动神经元中诱发了超极化。在低钙/高镁盐溶液中，运动神经元中超极化的幅度逐渐降低。向神经纤维网局部压力注射γ-氨基丁酸（GABA）会使运动神经元产生类似的超极化。这些生理学研究表明，非锋电位中间神经元与运动神经元之间存在GABA能抑制性相互作用。运动前非锋电位中间神经元分为后外侧（PL）和前外侧（AL）中间神经元两个亚组，AL中间神经元进一步分为三个亚型。将非锋电位局部中间神经元用荧光黄进行细胞内染色与用抗GABA抗血清进行免疫细胞化学染色相结合，结果显示，本研究中采样的所有PL中间神经元均显示出GABA样免疫反应性。一群直径较小（15 - 30微米）的细胞体（n = 6 - 11）聚集在一起形成一个簇，显示出GABA样免疫反应性，并且大多数PL中间神经元的细胞体都在这个簇中。为了比较PL中间神经元主要分支的数量和模式，将细胞分为三组可识别的中间神经元，称为PL - 1、PL - 2和PL - 3。相比之下，约一半的AL中间神经元，尤其是细胞体位于神经节腹外侧部的AL中间神经元第三亚型，未显示出GABA样免疫反应性。此外，与PL中间神经元相比，GABA免疫反应性AL中间神经元的细胞体位置较为分散。
