Dopaminergic neuromodulation of synaptic transmission between mitral and granule cells in the teleost olfactory bulb
Dopaminergic neuromodulation of synaptic transmission between mitral and granule cells in the teleost olfactory bulb
复制标题
硬骨鱼嗅球二尖瓣和颗粒细胞之间突触传递的多巴胺能神经调节
DOI：
10.1152/jn.00536.2011
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发表时间：
2012
影响因子：
2.5
通讯作者：
Oka Y
中科院分区：
文献类型：
--
作者：
Kawai T;Abe H;Oka Y
越来越多的证据表明，硬骨鱼是研究嗅觉信息神经处理的重要模型，而多巴胺 (DA) 的功能作用是哺乳动物嗅球内源性的有效神经调节剂，一直是该领域最受关注的焦点之一。然而，嗅球神经回路中多巴胺能神经调节的细胞机制尚未完全了解。我们利用金鱼研究了这种机制，金鱼为通过电生理方法分析嗅觉信息处理提供了多种优势。首先，我们发现在嗅球中，大量的多巴胺能神经元细胞体主要分布在二尖瓣细胞层，并向肾小球层延伸出细突。接下来，我们进行了体外场电位记录，结果表明，从二尖瓣到颗粒细胞的突触传递被 DA 应用所抑制。 DA 还增加了配对脉冲比，表明突触传递的抑制是由二尖瓣细胞突触前谷氨酸释放减少引起的。此外，DA 显着抑制嗅球响应嗅觉刺激的振荡活动。尽管DA抑制哺乳动物中从嗅觉神经到嗅球神经元的突触输入，但在金鱼中没有观察到这种现象。这些发现表明，抑制二尖瓣到颗粒细胞相互突触中的突触传递在金鱼嗅球嗅觉反应性的负调节中起着重要作用。
A growing body of evidence suggests that teleosts are important models for the study of neural processing of olfactory information, and the functional role of dopamine (DA), which is a potent neuromodulator endogenous to the mammalian olfactory bulb, has been one of the strongest focuses in this field. However, the cellular mechanisms of dopaminergic neuromodulation in olfactory bulbar neural circuits have not been fully understood. We investigated such mechanisms by using the goldfish, which offers several advantages for analyzing olfactory information processing by electrophysiological methods. First, we found in the olfactory bulb that numerous cell bodies of the dopaminergic neurons are mainly distributed in the mitral cell layer and extend fine processes to the glomerular layer. Next, we made in vitro field potential recordings and showed that synaptic transmissions from mitral to granule cells were suppressed by DA application. DA also increased the paired-pulse ratio, suggesting that the suppression of synaptic transmission is caused by a decrease in presynaptic glutamate release from the mitral cells. Furthermore, DA significantly suppressed the oscillatory activity of the olfactory bulb in response to olfactory stimuli. Although DA suppresses the synaptic inputs from the olfactory nerve to the olfactory bulbar neurons in mammals, this phenomenon was not observed in the goldfish. These findings indicate that suppression of the mitral to granule cell synaptic transmission in the reciprocal synapses plays an important role in the negative regulation of olfactory responsiveness in the goldfish olfactory bulb.