Postnatal development of GABA-ergic neurons in the rabbit retina.
Postnatal development of GABA-ergic neurons in the rabbit retina.
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兔视网膜中 GABA 能神经元的出生后发育。
DOI：
10.1002/cne.901930107
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
Kong,YC
中科院分区：
文献类型：
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作者：
Lam,DM;Fung,SC;Kong,YC
γ-氨基丁酸（GABA）的摄取、合成、储存和释放是GABA能神经元的一些特征。在本研究中，我们使用这些特性作为生理探针来跟踪兔视网膜出生后发育过程中GABA能神经元的出现和成熟。放射自显影、免疫细胞化学和药理学证据表明，一些无长突细胞和神经节细胞层中的某些神经元可能使用GABA作为神经递质。这些神经元摄取GABA，含有GABA合成酶L-谷氨酸脱羧酶（GAD，EC 4.1.1.15），并在高细胞外K+浓度去极化时通过Ca++依赖性机制释放积累的GABA。在这项研究中，我们表明，某些神经元在新生儿视网膜已经拥有一个特定的机制，GABA的摄取。这些细胞在发育中的视网膜中的位置和数量表明它们将成为成年视网膜中的GABA能神经元。然而，这些假定的GABA能神经元可能在出生时还不成熟，因为新生儿视网膜仅含有低水平的GABA和GAD。此外，新生儿视网膜中K+刺激的Ca++依赖性（3 H）-GABA释放相对较少。GABA浓度和GAD活性在发育中的视网膜出生后稳步增加，到第9天达到成人水平的约80%。GABA降解酶GABA-谷氨酸转氨酶（GABA-T，EC 2.6.1.19）的活性在视网膜发育期间遵循类似的成熟模式。K+刺激的GABA释放，然而，保持低，直到约6天，然后急剧增加，从20%到85%的成人水平在接下来的3天。两者合计，我们的研究结果表明，在兔子视网膜，承诺由某些神经元使用GABA作为递质产前。这些神经元在出生时是不成熟的，但在出生后约9天，在生物化学、生理学和可能的功能上是成熟的。
Uptake, synthesis, storage, and release of γ‐aminobutyric acid (GABA) are some of the characteristic properties of GABA‐ergic neurons. In the present study, we have used these properties as physiological probes to follow the emergence and maturation of GABA‐ergic neurons during postnatal development of the rabbit retina. There is autoradiographic, immunocytochemical, and pharmacological evidence that some amacrine cells and certain neurons in the ganglion cell layer probably use GABA as the neurotransmitter. These neurons take up GABA, contain the GABA‐synthesizing enzyme L‐glutamic acid decarboxylase (GAD, EC 4.1.1.15), and release the accumulated GABA by a Ca++‐dependent mechanism when depolorized with high extracellular K+concentration. In this study, we show that certain neurons in the newborn retina already possess a specific mechanism for GABA uptake. The positions and numbers of these cells in the developing retina suggest that they will become GABA‐ergic neurons in the adultretina. These putative GABA‐ergic neurons are, however, probably immature an birth because newborn retinas contain only low levels of GABA and GAD. Additionally, there is relatively little K+‐stimulated, Ca++‐dependent release of (3H)‐GABA from the newborn retinas. GABA concentrations and GAD activities in developing retinas increase steadily postnatally, reaching about 80% of the adult levels by day 9. The activities of the GABA‐degrading enzyme, GABA‐glutamate transaminase (GABA‐T, EC 2.6.1.19), follow a similar pattern of maturation during retinal development. K+stimulated GABA release, however, remains low until about day 6, and then increases dramatically from 20% to 85% of the adult level over the next 3 days. Taken together, our results indicate that in the rabbit retina, the commitment by certain neurons to use GABA as the transmitter is made prenatally. These neurons are immature at birth but are biochemically, physiologically, and probably functionally mature by about 9 days after birth.