Properties of the masticatory muscle piimary afferents from the trigeminal ganglion in the rats

本研究的主要发现如下：(1)逆行标记的肌肉传入神经元明显大于逆行标记的皮肤传入神经元，而逆行标记的皮肤传入神经元明显少于逆行标记的皮肤传入神经元。(2)α-D-半乳糖特异性凝集素IB4在6%的肌肉和44%的皮肤传入中有结合，显示出靶向特异性差异。(3)咬肌注射完全弗氏佐剂(CFA)诱导肌肉炎症实验表明，炎症后4天，三叉神经节肌肉传入神经元对CGRP和SP免疫反应的百分率无明显变化。(4)肌肉炎症导致注射CFA后12d三叉神经节肌肉传入神经元数量增加。提示肌肉炎症后增加的肽能神经元同样来自三叉神经的III和IV类肌肉传入。(5)在三叉神经节中，P2X3受体不是仅在IB4神经元中表达，而是包括较大的神经元。P2X3和IB4的表达存在靶向性差异。此外，提示深部组织炎症可以调节表达P2X3受体的神经元的数量。

The main findings of this research project are as follows:(1) Rerogradely labeled muscle afferent neurons were significantly lager and fewer than retrogradely labeled cutaneous afferent neurons. (2) α-D-galactose specific lectin IB4 binding was found in 6% of muscle and 44% of cutaneous afferents indicating a target specific difference. (3) The experiments inducing muscle inflammation by injecting complete Freund's adjuvant (CFA) to masseter muscle indicate that the percentage of trigeminal ganglion muscle afferent neurons immunoreactive for CGRP or SP does not change significantly four days after inflammation. (4) Muscle inflammation resulted in increased number of CGRP and substance P positive trigeminal ganglion muscle afferent neurons 12 days after CFA injection. It is suggested that the increased number of peptidergic neurons following muscle inflammation is recruited equally from trigeminal group III and IV muscle afferents. (5) It is indicated that in trigeminal ganglia, P2X3 receptor is not exclusively expressed in IB4 neurons but includes larger neurons. Target specific differences exist in P2X3 and IB4 expression. Furthermore, it is suggested that deep tissue inflammation can modulate the number of neurons expressing the P2X3 receptor.