Higo Noriyuki, Oishi Takao, Yamashita Akiko, Matsuda Keiji, Hayashi Motoharu
Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan.
Vis Neurosci. 2002 Sep-Oct;19(5):633-43. doi: 10.1017/s0952523802195083.
We performed a nonradioactive in situ hybridization histochemistry (ISH) study of the lateral geniculate nucleus (LGN) and the primary visual area (area 17) of the macaque monkey to investigate mRNA expression of the myristoylated alanine-rich C-kinase substrate (MARCKS), a major protein kinase C (PKC) substrate. In the LGN, intense hybridization signals were observed in both magnocellular neurons (layers 1 and 2) and parvocellular neurons (layers 3 to 6). Double labeling using ISH and immunofluorescence revealed that MARCKS mRNA was coexpressed with the alpha-subunit of type II calcium/calmodulin-dependent protein kinase, indicating that MARCKS mRNA is also expressed in koniocellular neurons in the LGN. GABA-immunoreactive neurons in the LGN did not contain MARCKS mRNA, indicating that MARCKS mRNA is not expressed in inhibitory interneurons. The signals were generally weak in area 17, and intense signals were restricted to large neurons in layers IVB, V, and VI. GABA-immunoreactive neurons in layers II-VI of area 17 did not contain MARCKS mRNA. Double-label ISH revealed that MARCKS mRNA was coexpressed with mRNA of GAP-43, another PKC substrate, in neurons of both the LGN and area 17. To determine whether the expression of MARCKS mRNA is regulated by retinal activity, we performed ISH in the LGN and area 17 of monkeys deprived of monocular visual input by tetrodotoxin. After monocular deprivation for 5 to 30 days, MARCKS mRNA was down-regulated in the LGN, but not in area 17. These results suggest that MARCKS mediates the activity-dependent changes in the excitatory relay neurons in the LGN.
我们对猕猴的外侧膝状体核（LGN）和初级视区（17区）进行了非放射性原位杂交组织化学（ISH）研究，以调查富含豆蔻酰化丙氨酸的蛋白激酶C底物（MARCKS）的mRNA表达，MARCKS是蛋白激酶C（PKC）的一种主要底物。在LGN中，在大细胞神经元（第1层和第2层）和小细胞神经元（第3至6层）中均观察到强烈的杂交信号。使用ISH和免疫荧光的双重标记显示，MARCKS mRNA与II型钙/钙调蛋白依赖性蛋白激酶的α亚基共表达，这表明MARCKS mRNA也在LGN的侏儒细胞神经元中表达。LGN中GABA免疫反应性神经元不含有MARCKS mRNA，这表明MARCKS mRNA在抑制性中间神经元中不表达。信号在17区通常较弱，强烈信号仅限于IVB、V和VI层的大神经元。17区II-VI层的GABA免疫反应性神经元不含有MARCKS mRNA。双重标记ISH显示，MARCKS mRNA与另一种PKC底物GAP-43的mRNA在LGN和17区的神经元中共表达。为了确定MARCKS mRNA的表达是否受视网膜活动调节，我们在被河豚毒素剥夺单眼视觉输入的猴子的LGN和17区进行了ISH。单眼剥夺5至30天后，LGN中的MARCKS mRNA被下调，但17区没有。这些结果表明，MARCKS介导了LGN中兴奋性中继神经元的活动依赖性变化。
