Instituto Cajal, CSIC, Avda del Doctor Arce Madrid, Spain ; CNRS UMR 6265, Centre des Sciences du Goût et de l'Alimentation Dijon, France ; Institut National de la Recherche Agronomique UMR 1324, Centre des Sciences du Goût et de l'Alimentation Dijon, France ; Université de Bourgogne UMR CSGA, Centre des Sciences du Goût et de l'Alimentation Dijon, France.
Front Neuroanat. 2012 Nov 8;6:44. doi: 10.3389/fnana.2012.00044. eCollection 2012.
It is well known that olfaction influences food intake, and conversely, that an individual's nutritional status modulates olfactory sensitivity. However, what is still poorly understood is the neuronal correlate of this relationship, as well as the connections between the olfactory bulb and the hypothalamus. The goal of this report is to analyze the relationship between the olfactory bulb and hypothalamus, focusing on orexin A immunostaining, a hypothalamic neuropeptide that is thought to play a role in states of sleep/wakefulness. Interestingly, orexin A has also been described as a food intake stimulator. Such an effect may be due in part to the stimulation of the olfactory bulbar pathway. In rats, orexin positive cells are concentrated strictly in the lateral hypothalamus, while their projections invade nearly the entire brain including the olfactory system. Therefore, orexin appears to be a good candidate to play a pivotal role in connecting olfactory and hypothalamic pathways. So far, orexin has been described in rats, however, there is still a lack of information concerning its expression in the brains of adult and developing mice. In this context, we revisited the orexin A pattern in adult and developing mice using immunohistological methods and confocal microscopy. Besides minor differences, orexin A immunostaining in mice shares many features with those observed in rats. In the olfactory bulb, even though there are few orexin projections, they reach all the different layers of the olfactory bulb. In contrast to the presence of orexin projections in the main olfactory bulb, almost none have been found in the accessory olfactory bulb. The developmental expression of orexin A supports the hypothesis that orexin expression only appears post-natally.
众所周知，嗅觉会影响食物摄入，反之，个体的营养状况也会调节嗅觉敏感度。然而，人们仍然不太了解这种关系的神经元相关性，以及嗅球和下丘脑之间的联系。本报告的目的是分析嗅球和下丘脑之间的关系，重点分析食欲素 A 免疫染色，这是一种下丘脑神经肽，被认为在睡眠/觉醒状态中发挥作用。有趣的是，食欲素 A 也被描述为一种促进食物摄入的物质。这种作用可能部分归因于对嗅球通路的刺激。在大鼠中，食欲素阳性细胞严格集中在外侧下丘脑，而它们的投射几乎侵入整个大脑，包括嗅觉系统。因此，食欲素似乎是连接嗅觉和下丘脑通路的一个很好的候选物。到目前为止，食欲素已在大鼠中进行了描述，但关于其在成年和发育中老鼠大脑中的表达仍缺乏信息。在这种情况下，我们使用免疫组织化学方法和共聚焦显微镜重新研究了成年和发育中小鼠中的食欲素 A 模式。除了细微的差异外，小鼠中的食欲素 A 免疫染色与在大鼠中观察到的有许多共同特征。在嗅球中，尽管食欲素的投射很少，但它们可以到达嗅球的所有不同层。与主要嗅球中存在食欲素投射相反，在副嗅球中几乎没有发现。食欲素 A 的发育表达支持这样的假设，即食欲素表达仅在出生后出现。
