López-Gallardo M, Prada C
Departamento de Fisiología, Facultad de Medicina, Universidad Complutense de Madrid, Spain.
Hippocampus. 2001;11(2):118-31. doi: 10.1002/hipo.1030.
Several studies have dealt with the morphogenesis of the rat hippocampal pyramidal cell, but little is known about how the different pyramidal cell shapes of CA fields differentiate from neuroepithelial cells, or about how the field morphological identity emerges. From our studies of pyramidal cell shapes in the CA1, CA3, and CA4 fields of hippocampi at postnatal developmental stages between P0 and P12, using fresh semidissociated slices and acutely dissociated cells, we identified the sequence of cell shape transformation by which they differentiate from simple bipolar to complex shapes characteristic of adult pyramidal cells of CA1 and CA3. Pyramidal cell morphogenesis does not occur synchronously throughout the CA hippocampus fields, but cells in the CA4 field undergo morphological differentiation at earlier stages, prenatally, than CA3 cells, and these in turn earlier than CA1 cells. Thus, during the P1-P6 stages, a gradient of shapes from less to greater differentiation was clearly observed from CA1 to CA4 in a single slice. Furthermore, a mixture of cells at different degrees of differentiation is observed in CA1 from P1 to P10, and in CA3 from P1 to P5. A gradient of shapes from more to less differentiation was observed at stages P5-P6 from septal to temporal. We describe two processes in the pyramidal cell morphogenesis in the CA1 and CA3 fields, the approximation to the soma of the point of bifurcation of the main apical process, and the acquisition of triangular shape of the soma, showing by a quantitative study of both processes that they occur earlier in CA3 than in CA1. Our study, therefore, provides new insight into rat pyramidal cell morphogenesis, and indicates that this process might be differently regulated in the various CA fields. Hippocampus
已有多项研究探讨了大鼠海马锥体细胞的形态发生，但对于CA区不同形态的锥体细胞如何从神经上皮细胞分化而来，以及该区的形态特征是如何形成的，我们却知之甚少。通过对出生后0至12天不同发育阶段海马CA1、CA3和CA4区锥体细胞形态的研究，我们使用新鲜的半解离切片和急性解离细胞，确定了细胞形态转变的序列，即它们从简单的双极形态分化为CA1和CA3区成年锥体细胞特有的复杂形态。锥体细胞的形态发生并非在整个CA海马区同步发生，而是CA4区的细胞在出生前比CA3区的细胞更早经历形态分化，而CA3区的细胞又比CA1区的细胞更早。因此，在出生后1至6天阶段，在单个切片中可清晰观察到从CA1到CA4区存在一个从低分化到高分化的形态梯度。此外，在出生后1至10天的CA1区以及出生后1至5天的CA3区，可观察到不同分化程度的细胞混合存在。在出生后5至6天阶段，从隔区到颞区观察到一个从高分化到低分化的形态梯度。我们描述了CA1和CA3区锥体细胞形态发生中的两个过程，即主要顶端突起分叉点向胞体的靠近以及胞体获得三角形形态，并通过对这两个过程的定量研究表明，它们在CA3区比在CA1区更早发生。因此，我们的研究为大鼠锥体细胞的形态发生提供了新的见解，并表明这一过程在不同的CA区可能受到不同的调控。海马体
