Mehra R D, Hendrickson A E
Department of Anatomy, All India Institute of Medical Sciences, New Delhi.
J Neurobiol. 1993 Jan;24(1):101-24. doi: 10.1002/neu.480240109.
The appearance of Substance P (SP) and Neuropeptide Y (NPY) has been studied using light microscopic immunocytochemical labeling throughout the complete developmental span of Macaca nemestrina monkey striate cortex. In the adult, 80% of the NPY+ neurons occur in the white matter (WM) and most of the remainder are medium to large multipolar neurons in layer 2. Fibers occur in all layers except 4C and are very numerous, given the relatively small number of NPY+ cell bodies. NPY+ neurons first were seen at embryonic day (E) 75. Most neurons were in the intermediate zone (IZ), but a few were in the immature cortical plate (CP). An adult-like distribution was present by E125 for neurons and by birth for fibers, but fiber staining intensity and number increased to postnatal year 1 (P1yr). In adult cortex, numerous SP+ nonpyramidal neurons were present in layers 2-6 and WM, but SP+ fibers were surprisingly infrequent. During development, significant numbers of SP+ neurons were not seen in the CP until E113-125. Later prenatal ages had a prominent plexus of SP+ cell bodies and fibers at the layer 5/6 border. This plexus disappeared by P12wk due to either down-regulation of SP or cell death. SP+ neurons in IZ/WM were very sparse until birth after which they increased in number and staining intensity up to P1yr, suggesting a postnatal up-regulation of SP in a preexisting WM subpopulation. Cell densities were determined for SP, NPY, and the neuron-specific marker microtubule-associated protein 2 (MAP2) to clarify the developmental dynamics of IZ/WM neurons. MAP2+ cell densities in WM peaked around birth and then declined 20% in the outer half and 77% in the inner half of WM. SP+ cell density rose 57% from birth to P20wk and then declined 20% into adulthood. NPY+ cell density was fairly constant prenatally and then rose 300% by adulthood. Neuropeptide cell density changes took place predominantly in the outer WM. These data indicate that cell death does occur in the general population of monkey striate cortical WM neurons. In contrast, both SP+ and NPY+ cells are characterized by minimal cell death and a late expression of neuropeptides which causes an increase in neuropeptide+ cell density in postnatal WM.
运用光镜免疫细胞化学标记技术，在食蟹猴纹状皮质的整个发育阶段，对P物质（SP）和神经肽Y（NPY）的出现情况进行了研究。在成年食蟹猴中，80%的NPY+神经元位于白质（WM），其余大部分是位于第2层的中大型多极神经元。除了4C层外，各层均有纤维，鉴于NPY+细胞体数量相对较少，纤维数量却很多。NPY+神经元最早在胚胎第75天（E75）被发现。大多数神经元位于中间带（IZ），但也有少数位于未成熟的皮质板（CP）。到E125时，神经元的分布已呈现出类似成年的状态，纤维在出生时也已如此，但纤维染色强度和数量在出生后第1年（P1yr）仍有增加。在成年皮质中，第2 - 6层和WM中有大量SP+非锥体神经元，但SP+纤维却出奇地稀少。在发育过程中，直到E113 - 125，CP中才出现大量SP+神经元。在产前后期，第5/6层边界处有一个明显的SP+细胞体和纤维丛。由于SP下调或细胞死亡，这个纤维丛在出生后第12周（P12wk）消失。IZ/WM中的SP+神经元在出生前非常稀少，出生后数量和染色强度增加，直至P1yr，这表明在已有的WM亚群中，SP在出生后上调。测定了SP、NPY以及神经元特异性标记物微管相关蛋白2（MAP2）的细胞密度，以阐明IZ/WM神经元的发育动态。WM中MAP2+细胞密度在出生时达到峰值，然后在WM的外半部分下降20%，内半部分下降77%。SP+细胞密度从出生到P20wk上升57%，然后在成年期下降20%。NPY+细胞密度在产前相当恒定，然后在成年期上升300%。神经肽细胞密度变化主要发生在外WM。这些数据表明，食蟹猴纹状皮质WM神经元总体中确实发生了细胞死亡。相比之下，SP+和NPY+细胞的特点是细胞死亡极少，神经肽表达较晚，这导致出生后WM中神经肽+细胞密度增加。
