Glezer Isaías, Malnic Bettina
Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
Department of Biochemistry, Institute of Chemistry, Universidade de São Paulo, São Paulo, Brazil.
Handb Clin Neurol. 2019;164:67-78. doi: 10.1016/B978-0-444-63855-7.00005-8.
Olfaction plays a critical role in several aspects of life. Olfactory disorders are very common in the general population, and can lead to malnutrition, weight loss, food poisoning, depression, and other disturbances. Odorants are first detected in the upper region of the nose by the main olfactory epithelium (OE). In this region, millions of olfactory sensory neurons (OSNs) interact with odor molecules through the odorant receptors (ORs), which belong to the superfamily of G protein-coupled receptors. The binding of odors to the ORs initiates an electrical signal that travels along the axons to the main olfactory bulb of the brain. The information is then transmitted to other regions of the brain, leading to odorant perception and emotional and behavioral responses. In the OE, OSNs die and are continuously replaced from stem cells localized in the epithelium's basal region. Damage to this epithelium can be caused by multiple factors, leading to anosmia (smell loss). In this chapter, we introduce the basic organization of the OE and focus on the molecular mechanisms involved in odorant perception. We also describe recent experiments that address the mechanisms of OSNs regeneration in response to neuronal injury.
嗅觉在生活的多个方面起着关键作用。嗅觉障碍在普通人群中非常常见，可能导致营养不良、体重减轻、食物中毒、抑郁及其他紊乱。气味分子首先由主嗅觉上皮（OE）在鼻腔上部区域被检测到。在该区域，数百万嗅觉感觉神经元（OSN）通过属于G蛋白偶联受体超家族的气味受体（OR）与气味分子相互作用。气味与OR的结合引发电信号，该信号沿着轴突传导至大脑的主嗅球。然后信息被传递至大脑的其他区域，从而产生气味感知以及情绪和行为反应。在OE中，OSN死亡并不断由位于上皮基底区域的干细胞替代。该上皮的损伤可由多种因素引起，导致嗅觉丧失（嗅觉减退）。在本章中，我们介绍OE的基本组织结构，并重点关注气味感知所涉及的分子机制。我们还描述了最近针对神经元损伤后OSN再生机制的实验。
