Differential Expression of GABA Transporters in Developing Rat Retina / 대한해부학회지

To investigate the spatial and temporal distribution of g-aminobutyric acid (GABA) transporters in the developing rat retina, we localized two GABA transporter proteins, GAT-1 and GAT-3 by immunocytochemistry. GAT-1 immunoreactivity appeared from embryonic day 20 (E20) in the punctate-like structures in the inner plexiform layer. At postnatal day 3 (P3), immunolabeling of cell bodies in the inner nuclear and ganglion cell layers and processes in the inner plexiform layer became much stronger, reaching a maximum staining intensity during the second postnatal week, and the expression pattern and intensity became almost identical to those of the adult retina by P14. In addition, Miller cells also began to show weak immunlabeling for GAT-1 from P10 onward. In contrast, develop-mentally transient immunolabeling for GAT-1 was found in horizontal cells located at the scleral border of the inner nuclear layer during the second postnatal week. The initial immunolabeling for GAT-3 immunoreactivity was already noted in scattered cell bodies and processes of the neuroblastic layer at E18, the earliest time point. During the first week of the postnatal life, GAT-3 immunoreactivity increased in the cell bodies in the inner nuclear and ganglion cell layers, and processes in the inner plexiform layer. From P10 onward, this labeling began to decline, and remained faintly in the neuronal somata of the inner nuclear layer by P14. Instead, the labeling was predominantly localized in Mler cells. Astrocytes in the nerve fiber layer showed the transient labeling during the first postnatal week. Our results showed distinct temporal patterns of two GABA transporter proteins in the developing rat retina, and it suggests specialized roles for GABA transporters in the development of the rat retina.

Expression of Nitric Oxide Synthase in the Olfactory Bulb of the Rat during Development / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The presence and distribution of NADPH-diaphorase activity in the olfactory bulb during development has been reported. But the precise localization of NO-synthase (NOS) in the olfactory bulb during the developmental stages has not been studied yet. Therefore, we investigated the localization of NOS-immunoreactivity in a developing rat olfactory bulb by immunohistochemistry. MATERIALS AND METHODS: A total of 32 male and female Sprague-Dawley rats. They were of several prenatal and postnatal stages, such as the following: embryonic day 16 (E16), E18, E20, postnatal day 1 (P1), P5, P7, P14 and adult. Indirect immunoperoxidase method using rabbit polyclonal anti-bNOS antibody was performed for detecting the NOS immunoreactivity. RESULTS: In the main olfactory bulb, the first NOS-immunoreactive (IR) neurons were observed in the presumptive granule cell layer (GCL) by E18, and in the glomerular layer (GL) by P1. The density of these neurons was increased as the development stage approached the adult stage. In the GCL, two types of NOS-immunoreactive neurons were observed: intensively stained large, short axon cells and weakly stained small, granule cells. The first, localized in the deeper part of the GCL, was observed in the earlier developmental stages, and the latter which increased in number to the adult period was observed by P1. In the accessory olfactory bulb, NOS-IR neurons were first detected in the GCL by P1, and increased in number to the adult period. The pattern of NOS-IR neurons in the GCL of the accessory olfactory bulb is similar to that in the main olfactory bulb. CONCLUSION: Our results demonstrated that bNOS had a characteristic temporal and spatial patterns of expression in the main and accessory olfactory bulb of the rat during development.