Roberts L A, Large C H, Higgins M J, Stone T W, O'Shaughnessy C T, Morris B J
Pharmacological laboratories, Division of Neuroscience and Biomedical Systems, Institute of Biomedical and Life Sciences, West Medical Building, Glasgow University, Glasgow, UK.
Brain Res Mol Brain Res. 1998 May;56(1-2):38-44. doi: 10.1016/s0169-328x(98)00026-6.
A small number of mRNAs, including Ca2+/calmodulin-dependent protein kinase II alpha-subunit (CamKIIalpha) mRNA and microtubule-associated protein 2 (MAP2) mRNA, are present in the dendrites of neurones as well as in the cell bodies. We show here that the induction of long-term potentiation (LTP) in the hippocampal perforant path/granule cell synapses in anaesthetised rats is associated with increased levels of CamKIIalpha mRNA and MAP2 mRNA in the granule cell dendrites after 2 h. Similarly, induction of LTP in the Schaffer collateral/CA1 pyramidal cell synapses in hippocampal slices maintained in vitro also results in elevated dendritic levels of CamKIIalpha mRNA and MAP2 mRNA 2 h later. In both models, the levels of various other mRNA species restricted to the cell body region were unaffected by the induction of LTP. Increased expression of dendritic CamKIIalpha mRNA and MAP2 mRNA appears to be a general feature of hippocampal plasticity, since it occurs following LTP induction in both the dentate gyrus and the CA1 region. The elevation of mRNA levels in a restricted region close to the afferent synapses would allow a highly-localised enhancement of the synthesis of the corresponding proteins, providing an elegant mechanism for protein-synthesis-dependent synaptic plasticity to maintain a high degree of anatomical specificity.
少数几种mRNA，包括钙/钙调蛋白依赖性蛋白激酶IIα亚基（CamKIIα）mRNA和微管相关蛋白2（MAP2）mRNA，不仅存在于神经元的细胞体中，也存在于树突中。我们在此表明，麻醉大鼠海马穿通通路/颗粒细胞突触中长时程增强（LTP）的诱导与2小时后颗粒细胞树突中CamKIIα mRNA和MAP2 mRNA水平的升高有关。同样，在体外维持的海马脑片中，施万细胞侧支/CA1锥体细胞突触中LTP的诱导也会在2小时后导致树突中CamKIIα mRNA和MAP2 mRNA水平升高。在这两种模型中，局限于细胞体区域的各种其他mRNA种类的水平不受LTP诱导的影响。树突中CamKIIα mRNA和MAP2 mRNA表达的增加似乎是海马可塑性的一个普遍特征，因为它在齿状回和CA1区的LTP诱导后都会发生。传入突触附近受限区域内mRNA水平的升高将允许相应蛋白质合成的高度局部增强，为依赖蛋白质合成的突触可塑性维持高度的解剖学特异性提供了一种精妙的机制。
