GABA样神经元和GABA能三叉一丘脑投射神经元在三叉神经感觉核簇的分布及形态学特征

用直接抗GABA免疫组化方法和与HRP逆行追踪相结合的双标记法在光镜下观察了GABA样神经元和GABA能丘脑投射神经元在大鼠三又神经惑觉核簇的分布和形态特征。结果显示:GABA样神经元广泛存在于三叉神经感觉核簇的各亚核中,但在每一亚核和尾侧亚核的各层,其分布状况和细胞形态特征各异。在尾侧亚孩,GABA样神经元的分布密度为Ⅰ、Ⅱ层>Ⅳ、Ⅴ层>Ⅲ层;在极间亚核,GABA样细胞分为背、腹二群,以腹侧群为主;在吻侧亚核,分为背内侧群、内侧带群和腹外侧群三群;在感觉主核分为背内侧群和腹外侧群;在三叉上核分为吻内侧群和尾外侧群。同样,本文首次发现,GABA能丘脑投射神经元也广泛存在于三叉神经感觉核簇各核中,而且在各亚核及各层中其分布密度及细胞形态也不相同。在尾侧亚核,双标细胞占38.6%,主要分布在Ⅰ、Ⅱ层,具有较长附突;在极间亚核,双标细胞占40%,主要分布在腹侧群;在吻侧亚核中仅在腹侧群有少量小的双标细胞;在感觉主核,双标细胞占20-30%,主要集中在背内侧群,腹外侧群仅有少量;在三叉上核,双标细胞仅出现在尾外侧群。结果提示:GABA对三叉神经感觉核簇中的各种深浅感觉功能的传导和整合可产生广泛的抑制影响,但其影响形式、程度和机制可能各不相同。

THE DISTRIBUTION AND MORPHOLOGICAL CHARACTERISTICS OF GABAERGIC NEURONS AND GABAERGIC TRIGEMINO-THALAMUS PROJECTING NEURONS IN THE TRIGEMINAL SENSORY NUCLEAR COMPLEX OF THE RAT

The distribution and morphological characteristics of GABAergic neurons and GABAergic trigemino-thalamus projecting neurons in the trigeminal sensory nuclear complex(TSNC)of the rat were studied by using direct anti-GABA immunohistochem istry combined with HRP retrograde tracing double labeling techniques. The GABAergic neurons existed extensively in the nuclei of the TSNC, however, different distributional and morphological features were noticed The density, of GABAergic neurons in different laminae of the subnueleus eaudalis of spinal trigeminal nucleus(Vsp)is laminae Ⅰ, Ⅱ>Ⅳ, Ⅴ>Ⅲ. The GABAergie neurons were divided into dorsal and ventral groups in the subnucleus interpolaris, and into 3 groups, i. e., dorsomedial, medial band and ventrolateral, in the subnueleus oralis of the Vsp. In. the trigeminal principal sensory nucleus (Vp)they divide.d into.dorsomedial and ventrolateral,, while in the supratrigeminal nucleus, rostromedial and eaudolateral groups could be identified.It was found, for the first time, that. GABAergic thalamus projecting neurons did also exist in the TSNC extensively and showed different distribution and cell morphol ogy. The percentage HRP-GABA double labeled neurons in the GABAergic cells was 38.6% in the caudalis of the Vsp, the majority of them were distributed in laminae Ⅰ and Ⅱ and they had long dendrites. HRP-GABA double labeled cells was 40%. in the interpolaris, a few of double labeled cells were observed in the ventrolateral group of the oralis. 20-30%HRP-GABA double labeled. neurons in the Vp, the majority of them appeared in the dorsomedial group. A small amount of double labeled neurons were seen in the caudolateral group of the supratrigeminal nucleus. The present results suggested that GABAergic neurons could play inhibitory role extensively to the transmission and integration of various trigeminal sensory functions, while the inhibition mechanisms, forms and degree might be different.