已知磷脂酰肌醇磷酸5激酶(PIP5K)γ和磷脂酶C(PLC)β3在磷酸肌醇循环中依次工作,位于背根神经节(DRG)躯体中,参与疼痛和相关感觉的调节。然而,他们参与的地点仍有待澄清。在本研究中,PLCβ3的免疫反应性仅在小鼠DRG的中心过程中不同,但不是在它的外围过程中,与外周和中枢DRG过程中不同的PIP5Kγ免疫反应性相反。在任何外周感觉视野中均未检测到显示PLCβ3免疫反应性的神经末梢,与PIP5Kγ免疫反应性相似。在DRGSONATA中,PIP5Kγ-免疫反应性相当局限于在3D明场光学显微镜下辨别点和线的神经外膜。此特征与免疫电子显微镜中沿质膜的不连续定位非常吻合。相比之下,PLCβ3-免疫反应性在整个躯体中扩散发生,但在神经膜或质膜上没有明显的免疫反应,与PIP5Kγ免疫反应性不同。此外,卫星胶质细胞对PLCβ3免疫阴性,但对PIP5Kγ免疫阳性。因此,认为PLCβ3参与调节疼痛和相关感觉的作用主要在DRG躯体及其上游水平上。但在外围感官领域不那么重要,类似于PIP5Kγ。这种可能性还表明,PIP,PIP5Kγ-靶,是异质局部的,但是PIP2,PLCβ3-靶,均匀地位于神经元质膜的平面上。研究重点:PIP5Kγ,与PLCβ3不同,不均匀地位于神经元膜上,这种差异在3D亮场免疫光和电子显微镜中得到了证明。在周围神经末梢中未检测到PIP5Kγ或PLCβ3。
It is known that phosphatidylinositol phosphate 5 kinase (PIP5K) γ and phospholipase C (PLC) β3, working sequentially in the phosphoinositide cycle, are localized in dorsal root ganglion (DRG) somata and are involved in the regulation of pain and related sensations. However, the sites of their involvement have remained to be clarified. In the present study, immunoreactivity for PLCβ3 was distinct only in the central process of mouse DRG, but not in its peripheral process, in contrast to distinct PIP5Kγ-immunoreactivity in both peripheral and central DRG processes. No nerve terminals showing immunoreactivity for PLCβ3 were detected in any peripheral sensory fields, similar to PIP5Kγ-immunoreactivity. In DRG somata,
PIP5Kγ-immunoreactivity was rather confined to the neurolemma in which dots and threads were discerned in 3D bright field light microscopy. This feature well corresponded to its discontinuous localization along the plasma membranes in immuno-electron microscopy. In contrast, PLCβ3-immunoreactivity occurred diffusely throughout the somata, but did not take distinct appearance of immunoreaction on neurolemma or plasma membranes, unlike PIP5Kγ-immunoreactivity. In addition, satellite glial cells were immunonegative for PLCβ3, but immunopositive for
PIP5Kγ. The involvement of PLCβ3 in regulation of pain and related sensations is thus suggested to be mainly exerted at levels of the DRG soma and its upstream, but to be less significant in the peripheral sensory fields, similar to PIP5Kγ. The possibility is also suggested that PIP,
PIP5Kγ-target, is localized heterogeneously, but PIP2, PLCβ3-target, is localized homogenously over the plane of the neuronal plasma membranes. RESEARCH HIGHLIGHTS:
PIP5Kγ, different from PLCβ3, was localized heterogeneously on neuronal membranes, and this difference was demonstrated in 3D-bright field immuno-light and electron microscopy. Either
PIP5Kγ or PLCβ3 was not detected in peripheral nerve terminals.