Jacobs K M, Neve R L, Donoghue J P
Department of Neuroscience, Brown University, Providence, Rhode Island 02912.
J Comp Neurol. 1993 Oct 1;336(1):151-60. doi: 10.1002/cne.903360112.
Calcium-calmodulin protein kinase II and GAP43 are two molecules which have been linked to synaptic plasticity. Localization of mRNA for these molecules identifies the neuronal populations which have the potential to utilize these mechanisms. General descriptions for calcium-calmodulin protein kinase II or GAP43 mRNA have been previously reported. In light of recent evidence that suggests that at some sites these two molecules may interact, we sought to determine the cortical distribution in detail, and to examine the extent of overlap between neuronal populations containing each mRNA. To this end we have used in situ hybridization techniques to study the distribution of calcium-calmodulin protein kinase II and GAP43 mRNA in adjacent sections of adult rat forebrain. Overall, the distribution patterns were distinct but partially overlapping. For both calcium-calmodulin protein kinase II and GAP43, mRNA levels were highest in hippocampus, allo- and neocortex, compared to moderate to low levels in striatum and thalamic nuclei. Within the heavily labeled regions certain populations expressed both calcium-calmodulin protein kinase II and GAP43 mRNA at high levels, while other populations were selective for calcium-calmodulin protein kinase II. In the hippocampus, the stratum pyramidale of CA1-3 expressed high levels of both calcium-calmodulin protein kinase II and GAP43 mRNA. Granule cells of the fascia dentata and the stratum radiatum of CA3 both contained moderate to high levels of calcium-calmodulin protein kinase II mRNA, but near background levels of GAP43 mRNA label. Within the neocortex, deep layers were distinguished from superficial layers by their lack of calcium-calmodulin protein kinase II mRNA expression within the neuropil, and the presence of GAP43 mRNA in neurons located in layer V and the deepest part of layer VI. Thus, layer V and deep layer VI neurons showed high levels of label for both GAP43 and calcium-calmodulin protein kinase II mRNA, while neurons of superficial layers contained only calcium-calmodulin protein kinase II mRNA. These markers differentiate neuronal populations which can also be distinguished on the basis of their ability to undergo specific forms of synaptic plasticity. These different forms of plasticity may be due in part to the laminar-specific patterns of GAP43 and calcium-calmodulin protein kinase II mRNA that we have described.
钙调蛋白激酶II和GAP43是两种与突触可塑性相关的分子。这些分子的mRNA定位可识别出具有利用这些机制潜力的神经元群体。先前已有关于钙调蛋白激酶II或GAP43 mRNA的一般描述。鉴于最近的证据表明这两种分子在某些部位可能相互作用，我们试图详细确定其在皮质的分布，并研究包含每种mRNA的神经元群体之间的重叠程度。为此，我们使用原位杂交技术研究成年大鼠前脑相邻切片中钙调蛋白激酶II和GAP43 mRNA的分布。总体而言，分布模式不同但部分重叠。与纹状体和丘脑核中的中低水平相比，钙调蛋白激酶II和GAP43的mRNA水平在海马体、异皮质和新皮质中最高。在标记密集的区域内，某些群体同时高水平表达钙调蛋白激酶II和GAP43 mRNA，而其他群体则对钙调蛋白激酶II具有选择性。在海马体中，CA1 - 3的锥体层高水平表达钙调蛋白激酶II和GAP43 mRNA。齿状回的颗粒细胞和CA3的辐射层都含有中高水平的钙调蛋白激酶II mRNA，但GAP43 mRNA标记接近背景水平。在新皮质中，深层与浅层的区别在于神经毡内缺乏钙调蛋白激酶II mRNA表达，以及位于V层和VI层最深部分的神经元中存在GAP43 mRNA。因此，V层和深层VI神经元对GAP43和钙调蛋白激酶II mRNA均显示高水平标记，而浅层神经元仅含有钙调蛋白激酶II mRNA。这些标记区分了神经元群体，这些群体也可以根据其经历特定形式突触可塑性的能力来区分。这些不同形式的可塑性可能部分归因于我们所描述的GAP43和钙调蛋白激酶II mRNA的层特异性模式。
