鸡脊髓运动神经元中钙离子通道α_2亚基和钠离子通道α亚基的免疫学表达

Immunolocalization of voltage-gated calcium channel α_2 subunit and sodium channel α subunit in chicken spinal motoneurons

目的观察电压门控钙离子通道α2(votage-gated calcium channel,VGCC)亚基和电压门控钠离子通道α(volt-age-gated sodium channel,VGSC)亚基在鸡脊髓运动神经元中的表达,并探讨相互表达的关系。方法应用免疫组织化学(ABC法)观察鸡脊髓前角神经元中CCα2亚基和SCα亚基的表达,并应用免疫荧光双标记法观察鸡脊髓运动神经元中CCα2亚基和SCα亚基表达的关系。结果 CCα2亚基主要表达于脊髓IX层的大型神经元中,Ⅷ层的部分小型神经元亦呈CCα2亚基免疫阳性,大约83%的脊髓运动神经元呈CCα2阳性。CCα2亚基免疫反应物位于神经元胞浆和近位树突中。SCα亚基免疫反应物主要表达于脊髓运动神经元细胞核中,或同时表达在神经元的细胞核及胞浆中。一些有髓轴突和神经元近位树突亦呈SCα亚基免疫强阳性。大约46%的运动神经元呈SCα亚基阳性,并所有SCα亚基免疫阳性运动神经元均为CCα2亚基阳性。结论脊髓运动神经元中CCα2亚基和SCα亚基有多样性表达,可能表明运动神经元的不同运动活性。

Objective The localization of the votage-gated calcium channel （VGCC） α2 subunits and the voltage-gated sodium channel （VGSC） α subunits was investigated in chicken spinal motoneurons. Methods We used immunohistochemical methods to examine the distribution of VGCC α2 subunit and VGSCα subunits in the chicken spinal motoneurons and determine their relationship. Results The CCα2 subunit immunoreaction （IR） was mainly present in large neurons in Lamina IX, and occasionally in small neurons of Lamina VIII. Approximately 83% of spinal motoneurons were positive for CCα2. The CCα2 subunit-IR was localized in the cytoplasm of neuronal somata and proximal dendrites. According to the staining intensity, CCα subunit-positive neurons were divided into 3 subgroups. The SCα subunit-IR was observed only in the nucleus, or in both the nucleus and cytoplasm of spinal neurons. Approximately 46 of motoneurons were positive for SCα, and almost all the motoneurons with SCα subunit-IR were positive for CCα2. Conclusion These findings demonstrate that the heterogeneous expressions of VGCCα2 and VGSCα subunits in the motoneurons may reflect various motor activities.