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

本研究主要发现如下：(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。(2) α- d -半乳糖特异性凝集素IB4结合在6%的肌肉和44%的皮肤传入神经中，表明了靶标特异性差异。(3)咬肌注射完全弗氏佐剂（CFA）诱导肌肉炎症实验表明，炎症4天后三叉神经节肌传入神经元对CGRP或SP免疫反应的百分比无明显变化。(4)肌肉炎症导致注射CFA后12天CGRP和P物质阳性三叉神经节肌传入神经元数量增加。这表明肌肉炎症后多肽能神经元数量的增加同样来自三叉神经III组和IV组肌肉传入神经。(5)提示在三叉神经节中，P2X3受体不仅在IB4神经元中表达，也包括更大的神经元。P2X3和IB4在靶特异性表达上存在差异。此外，这表明深层组织炎症可以调节表达P2X3受体的神经元数量。

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.