Betarbet R, Zigova T, Bakay R A, Luskin M B
Department of Anatomy and Cell Biology, Emory University School of Medicine, Atlanta GA 30322, USA.
Int J Dev Neurosci. 1996 Nov;14(7-8):921-30. doi: 10.1016/s0736-5748(96)00066-4.
Earlier studies in our laboratory have demonstrated that a discrete region of the anterior part of the neonatal subventricular zone (SVZa) contains exclusively neuronal progenitor cells. The descendants of the SVZa progenitor cells are destined for the granule cell and glomerular layers of the olfactory bulb, where they differentiate into granule and periglomerular cells, the interneurons of the olfactory bulb, respectively. In the present set of experiments we examined the neurotransmitter phenotype of the SVZa-derived cells. In order to label SVZa-derived cells, the cell proliferation marker bromodeoxyuridine (BrdU) was injected into the SVZa of postnatal day 2 (P2) rats. After 3 weeks, by which time most of the SVZa-derived cells have migrated to their final destination in the bulb, the animals were perfused and their brains processed for immunohistochemistry. To identify the neurotransmitter phenotype of the SVZa-derived cells, sagittal sections of the forebrain, including the olfactory bulb, were double-labeled with an antibody to BrdU in conjunction with an antibody to gamma-amino-butyric acid (GABA) or tyrosine hydroxylase (TH), the rate limiting enzyme in the synthesis of dopamine. Using simultaneous indirect immunofluorescence to detect the presence of single- and double-labeled cells, we found that 59% and 51% of the BrdU-positive cells were immunoreactive for GABA in the granule cell and glomerular layers, respectively. In addition, 10% of the BrdU-positive periglomerular cells were immunoreactive for TH. The presence of double-labeled (BrdU-positive/GABA-positive and BrdU-positive/TH-positive) cells in the olfactory bulb, demonstrates that the SVZa is a source of the GABAergic and dopaminergic interneurons of the olfactory bulb during postnatal development.
我们实验室早期的研究表明，新生大鼠脑室下区前部（SVZa）的一个离散区域仅包含神经祖细胞。SVZa祖细胞的后代注定要迁移到嗅球的颗粒细胞层和肾小球层，在那里它们分别分化为颗粒细胞和球周细胞，即嗅球的中间神经元。在本系列实验中，我们研究了SVZa衍生细胞的神经递质表型。为了标记SVZa衍生细胞，将细胞增殖标记物溴脱氧尿苷（BrdU）注射到出生后第2天（P2）大鼠的SVZa中。3周后，此时大多数SVZa衍生细胞已迁移到嗅球的最终目的地，对动物进行灌注，并对其大脑进行免疫组织化学处理。为了确定SVZa衍生细胞的神经递质表型，对包括嗅球在内的前脑矢状切片进行双重标记，使用抗BrdU抗体与抗γ-氨基丁酸（GABA）或酪氨酸羟化酶（TH，多巴胺合成中的限速酶）抗体结合。通过同时进行间接免疫荧光检测单标记和双标记细胞的存在，我们发现颗粒细胞层和肾小球层中分别有59%和51%的BrdU阳性细胞对GABA有免疫反应。此外，10%的BrdU阳性球周细胞对TH有免疫反应。嗅球中双标记（BrdU阳性/GABA阳性和BrdU阳性/TH阳性）细胞的存在表明，在出生后发育过程中，SVZa是嗅球GABA能和多巴胺能中间神经元的来源。
