大鼠三叉神经节细胞向三叉神经脊束核各亚核的分枝投射

本文应用荧光素双标记与免疫荧光结合方法研究了单个含ＳＰ或ＣＧＲＰ的三叉神经节细胞向三叉神经脊束核的尾侧亚核、极间亚核和吻侧亚核的分枝投射。将ＤｉａｍｉｄｉｎｏＹｅｌｌｏｗ（ＤＹ）注入尾侧亚核，ＦａｓｔＢｌｕｅ（ＦＢ）分别注入吻侧亚核或极间亚核，发现ＤＹ／ＦＢ双标细胞占同侧三叉神经节内标记细胞总数的１３．２％（ＦＢ注入吻侧亚核例）和２．３％（ＦＢ注入极间亚核例）；双标细胞中含ＳＰ者分别为７４．４％和６９．６％；含ＣＧＲＰ者分别为７２．１％和６４．３％。将ＤＹ注入极间亚核，ＦＢ注入吻侧亚核时，ＤＹ／ＦＢ双标细胞占同侧三叉神经节标记细胞总数的１．６％，双标细胞中有６７．９％为ＳＰ阳性，７３．９％为ＣＧＲＰ阳性。多数的双标且呈ＳＰ或ＣＧＲＰ阳性的三叉神经节细胞直径约为２５～５０μｍ，为中、小型节神经元，而直径大于５０μｍ的大型细胞较少见。以上结果提示，三叉神经初级传入纤维进入脑干后的下降支分枝投射向三叉神经脊束核的各亚核，它们可能与面口部的痛信息传递有关。ＳＰ和ＣＧＲＰ是这些分支投射神经元的重要神经活性物质。

COLLATERAL PROJECTIONS OF TRIGEMINAL GANGLION NEURONS TO DIFFERENT SUBNUCLEI OF THE SPINAL TRIGEMINAL NUCLEUS IN THE RAT

Employing a combination of flurorescent retrograde double labeling and immunofluorescence histochemistry for substance P(SP)or calcitonin gene-related peptide (CGRP), we examined collateral prorctions from single neuronal cell bodies in the trigeminal ganglion (TG)of the rat to caudal, interpolar or oral subnuclei of the spinal trigeminal nucleus(Vc,Vi or Vo).In the rats that were unilaterally injected with Diamidino Yellow (DY) into the Vc and with Fast BIue (FB) into the Vo or Vi, and with DY into the Vi and with FB into the Vo, neuronal cell theies labeled with DY and/or FB were observed in the TG ipsilateral to the injections. Of the labeled TG neuronal cell bodies, about 13.2% or 2.3% were double labeled with both tracers in the rat that were injerted with DY into the Vc and with FB into the Vo or Vi, and about 1.6 % were double labeled in the rats that were injected with DY into the Vi and with FB into the Vo. The results indicated that TG neuronal cells sending their axons to the Vc projert, by way of axon collateral, to the Vo more frequently than to the Vi.Some of the TG neuronal cell bodies double labeled with DY and FB exhibited SP- or CGRP-like immunoreactivities (LI). Of the TG neuronal cell bodies that were double labeled with DY injected into the Vc and with FB into the Vo or Vi, about 74.4% or 69. 9%, respectively, displayed SP-LI, and about 72.1% or 64.3%, respectively, showed CGRP-LI; and with DY injected into the Vi and with FB into the Vo, about 67. 9% or 73. 9%, respectively, exhibited SP-LI or CGRP-LI. The maximal soma diameter of these DY and FB double labeled neuronal cell bodies with SP-LI or CGRPP-LI ranged from 15 to 80 μm,the majority measuring less than 50 μm. Some of the SP- or CGRPLI TG neuronal cells that were double labeled with DY and FB were assumed to mediate pain signals to the different subnuclei of the spinal trigeminal nucleus by way of axon collalerals.