Ringstedt T, Lagercrantz H, Persson H
Department of Medical Chemistry, Karolinska Hospital, Stockholm, Sweden.
Brain Res Dev Brain Res. 1993 Mar 19;72(1):119-31. doi: 10.1016/0165-3806(93)90165-7.
Tyrosine protein kinases trk, trkB and trkC are essential components of the high affinity receptors necessary to mediate biological effects of the neurotrophins NGF, BDNF, NT-3 and NT-4. Here we report on the expression of these receptors during postnatal development in the rat brain. Cells expressing mRNAs encoding different members of the trk family were identified by in situ hybridization using oligonucleotides complementary to their respective mRNA. In septum, striatum and brainstem, higher levels of trk mRNA were detected at 2 and 4 weeks than at 1 weeks of age. In thalamic nuclei associated with the limbic system, trkB and trkC mRNA were highly expressed at P1 to P7, but the expression declined gradually in 2 and 4 week old animals. Other structures where a developmentally regulated expression was seen included the tenia tecta and piriform cortex where trkB mRNA was not detected until 2 weeks of age. A high labeling was found for trkC mRNA in the deeper parts of neocortex in P1 and P4 animals, while in 2 and 4 weeks old animals the highest labeling was seen over the outer neocortical layers. Several brainstem nuclei showed a higher labeling for trkC mRNA at P1 to P7 than in animals of older age. These data show that expression of members of the trk family is developmentally regulated during postnatal brain development and suggest that high affinity neurotrophin receptors mediate a transient response to neurotrophins in many regions during brain ontogeny.
酪氨酸蛋白激酶trk、trkB和trkC是介导神经营养因子NGF、BDNF、NT - 3和NT - 4生物学效应所必需的高亲和力受体的重要组成部分。在此，我们报告这些受体在大鼠脑出生后发育过程中的表达情况。通过使用与其各自mRNA互补的寡核苷酸进行原位杂交，鉴定出表达编码trk家族不同成员mRNA的细胞。在隔区、纹状体和脑干中，trk mRNA在2周和4周时的表达水平高于1周龄时。在与边缘系统相关的丘脑核中，trkB和trkC mRNA在出生后第1天到第7天高度表达，但在2周龄和4周龄动物中表达逐渐下降。其他观察到有发育调控表达的结构包括 tenia tecta和梨状皮质，其中trkB mRNA直到2周龄才被检测到。在出生后第1天和第4天的动物中，trkC mRNA在新皮质较深部位有高标记，而在2周龄和4周龄动物中，最高标记出现在新皮质外层。几个脑干核在出生后第1天到第7天的trkC mRNA标记高于年龄较大的动物。这些数据表明，trk家族成员的表达在出生后脑发育过程中受到发育调控，提示高亲和力神经营养因子受体在脑个体发育过程中在许多区域介导对神经营养因子的短暂反应。
