Several Neural Plasticity-related Molecular Expression In Mice After Birth And The Dynamic Of The Songbird Brain

The collapsin response mediator protein-4 (CRMP-4) is a member of CRMP family that is involved in neuronal differentiation and regulation of synaptic rearrangement. The brain of songbird is well known for its neural plasticity. To disclose the potential actions of CRMP-4 in the songbird brain, we first obtained CRMP-4 cDNA from the brain of a songbird (Lonchura striata) by use of RT-PCR and 3' rapid amplification of cDNA ends (3'RACE). We then examined the expression of CRMP-4 mRNA and protein in the adult brain, with emphasis on several plastic areas. To further determine the phenotypes of CRMP-4 expressing cells, double immunohistochemistry was employed by using antibodies for immature neurons (anti-HuD), mature neurons (anti-NeuN orα-tubulin), astrocytes (anti-GFAP), cells undertaking axonal growing (anti-GAP-43), and proliferating cells (anti-BrdU). Here, we showed that: 1) two fragments of CRMP-4 cDNA (502bp, 798bp) were cloned, and both showed high similarity with those comparable cDNA of reported species, indicating the evolutionary conservation of CRMP-4; 2) both CRMP-4 mRNA and protein were found to be mainly located in song control nuclei and cerebellum, by using in situ hybridization and immunocytochemistry, respectively; CRMP-4 protein also appeared very long projections; 3) some CRMP-4 positive cells also labeled by the antibody for HuD, but not for NeuN,α-tubulin, GFAP, GAP-43, and BrdU. Mitosis marker-BrdU did not express in CRMP-4 positive cells of adult songbird brain. We can infer from our results: CRMP-4 played similar roles in brains of different species. The presence of CRMP-4 in the regions displaying neural plasticity suggests that CRMP-4 may play an important role in the synaptic reorganization in the songbird brain. CRMP-4 mainly appeared those areas that displayed adult axon outgrowth and/or synapse reorganization. These indicated that CRMP-4 maybe marker of consecutive synapse genesis or spare rejection change, followed with neuron transition. CRMP-4 protein expressed not only in growing axon, but also in other"plastic"events. CRMP-4 perhaps be involved neural plasticity with HuD,α-tubulin or GAP-43. And CRMP-4 positive cells should not be generated in adulthood.The collapsin response mediator protein-4 (CRMP-4) is a member of CRMP family that is involved in neuronal differentiation and regulation of synaptic rearrangement. The brain of songbird is well known for its neural plasticity. To disclose the potential actions of CRMP-4 in the songbird brain, we first compared the postnatal developmental expression in brain of a songbird(Lonchura striata).Through examing the dynamic change of CRMP-4 protein in the songbird brain from P10 to adult stage, we especially studied some brain nuclei which had neural plasticity and included song control nucle(iHVC, RA, LMAN, DLM and NCM)and auditory nuclei(OV, MLd and NM)。To further determine the phenotypes and characters of CRMP-4 expressing cells. Here, we showed that: 1) CRMP-4 protein was found to be located in song control nuclei (HVC, RA, LMAN, DLM and NCM)and auditory nuclei(OV, MLd and NM ) throug postnatal development to adulthood by using immunocytochemistry; 2) the labeled density of CRMP-4 declined after postnatal development. On the other hand, the CRMP-4 labeled cell shape had change with age. When the bird had been hatched for less than 20 days, the labeled cells were oval and had short processes. While the bird came to adulthood, the cells had more than two shapes. The presence of CRMP-4 in the regions displaying neural plasticity suggests that CRMP-4 may play an important role in the synaptic reorganization in the songbird brain. And the neural plasticity declined with age in songbird brain.Collapsin-1,GAP-43,Neuropilin-1,Netrin-1and Neurofilament are involved in the neuron differentiation and the regulation of synapse reorganization. The neural growth–associated protein GAP-43 has properties of a general intrinsic determinant of anatomical plasticity. Its expression in neurons correlates closely with axonal elongation, synaptogenesis, and nerve sprouting during development and in the adult. It has also been suggested that Collapsin-1 might play a role in scar formation in the adult CNS, angiogenesis, and inhibition of axon regeneration. Collapsin-1 has been shown to play a role in the migration and regeneration of neocortical neurons. A possible explanation for the involvement of the semaphorins in cell migration and metastasis comes from the observation that semaphorins, especially Col1apsin-1, modulate not only the path-finding of axons, but also the migration of neural progenitor cells. This suggests more general effects of semaphorins on the cytoskeleton, apart from effects on axonal growth cones. Col1apsin-1signaling is mediated by a receptor complex involving Neuropilin-1. Neuropilin-1 positive neurites assessed morphologically the distribution of Neuropilin-1 in their growth cones. Neuropilin proteins has motifs serving a variety of molecular interactions, suggesting diverse functions for these molecules. Gradients of guidance cues and neurotrophic factors induce localized directional changes in growth cones and their axons. Netrin-1 could locally induce new axonal growth and promote localized directed axon branching.Mammal hippocampous is well known to be an area which has neural plasticity. To further explore the potential functions in the mammal hippocampous, we first compared the postnatal developmental expression of Collapsin-1 , GAP-43 ,Neuropilin-1,Netrin-1 and Neurofilament in brain of mouse. To further determine the phenotypes and characters of CRMP-4 expressing cells and expression pattern of CRMP-4 labeled regions, we can know the temporal and spatial dynamics of neural plasticity in mammal hippocampous.Our results indicated that 1) High expression of GAP-43 protein was found in the hippcampus during the first postnatal week, but subsequently its expression is gradually reduced and almost completely disappears by P30. P3 it sparsely distributed in subregions of hippocampus; P5-8 it was mainly located in dentate gyrus and highly expressed; P10-30 it only can be seen in stratum oriens, stratum radiatum and lacunosum moleculare.While moderate expression of GAP-43 protein was found in all parts of the hippcampus throughou adulthood. High expression during young dentate gyrus indicated that most of the neural connections began after postnatal stage. The presence of GAP-43 in the mature nervous system istaken to indicate a potential of these regions for plastic remodeling depending on sensory experience or learning. 2) Collapsin-1,Neuropilin-1 and Netrin-1positive cells were almost located in the whole hippocamous and coexpressed in the same cells. Collapsin-1,Neuropilin-1 and Netrin-1 may cancel most abnormal neural connections and maintained those connected or connecting in hippocampus,thus reaching high efficiency of neural system. Collapsin-1 has a variety of functions in the developing and maturenervous system. 3) Neurofilament labeled fibers declined with age. So neural projections were mainly built in early developmental postnatal stage, but maintained into adulthood. 4) GAP-43 was coexpressed with Collapsin-1or Neurofilament, indicating that cells with synapse connections were rejecting wrong events and changing in themselves.In view of the possibility that GAP-43 , Neuropilin-1 , Netrin-1 and Neurofilament might play a role in plasticity of synaptic contacts in the mammal hippocampus system, we have examined the anatomical distribution of their proteins in hippocampus system of the postnatal developing and mature mice. Double label was employed to show that neurons which could enclose the possible fuctions of these molecules. Based on their expression pattern and its previously documented chemattractive or chemorepulsive properties during development, we discuss a potential role of them in structural plasticity of the mammal hippocampus.Collapsin-1,GAP-43,Neuropilin-1,Netrin-1and Neurofilament are involved in the neuron differentiation and the regulation of synapse reorganization. In view of the possibility that GAP-43,Neuropilin-1,Netrin-1 and Neurofilament might play a role in plasticity of synaptic contacts in the mammal cerebellar system.. Mammal cerebellum is well known to be an area which has neural plasticity. To further explore the potential functions in the mammal cerebellum, we first compared the postnatal developmental expression of them in brain of mouse. Double label was employed to show that neurons which could enclose the possible fuctions of these molecules We can know the temporal and spatial dynamics of neural plasticity in mammal cerebellum.The neural growth–associated protein GAP-43 has properties of a general intrinsic determinant of anatomical plasticity. Its expression in neurons correlates closely with axonal elongation, synaptogenesis, and nerve sprouting during development and in the adult. It has also been suggested that Collapsin-1 might play a role in scar formation in the adult CNS, angiogenesis, and inhibition of axon regeneration. Collapsin-1 has been shown to play a role in the migration and regeneration of neocortical neurons. A possible explanation for the involvement of the semaphorins in cell migration and metastasis comes from the observation that semaphorins, especially Col1apsin-1, modulate not only the path-finding of axons, but also the migration of neural progenitor cells. This suggests more general effects of semaphorins on the cytoskeleton, apart from effects on axonal growth cones. Col1apsin-1signaling is mediated by a receptor complex involving Neuropilin-1. Neuropilin-1 positive neurites assessed morphologically the distribution of Neuropilin-1 in their growth cones. Gradients of guidance cues and neurotrophic factors induce localized directional changes in growth cones and their axons. Netrin-1 could locally induce new axonal growth and promote localized directed axon branching.Our results indicated that 1) High expression of GAP-43 protein was found in the cerebellum during the first postnatal week, but subsequently reduced only in molecular zone by P10-90. High expression during young cerebellum indicated that most of the neural connections began after early postnatal stage and stopped soon. 2) Collapsin-1,Neuropilin-1 and Netrin-1positive cells were almost coexpressed in the same Purkinje cells. Collapsin-1,Neuropilin-1 and Netrin-1 may delete most abnormal neural connections and maintained those connected or connecting in cerebellum, thus reaching high efficiency of neural system. 3) Neurofilament labeled fibers declined with age. So neural projections were mainly built in early developmental postnatal stage.Based on their expression pattern and its previously documented chemattractive or chemorepulsive properties during development and their expression pattern, we discuss a potential role of them in structural plasticity and neural connection competitions of the mammal cerebellum in molecular level, thus offering research model of brain development and plasticity.