Division of Brain Structure and Function, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
Life Science Innovation Center, University of Fukui, Fukui, Japan.
Front Neural Circuits. 2024 May 30;18:1408189. doi: 10.3389/fncir.2024.1408189. eCollection 2024.
Olfactory dysfunctions decrease daily quality of life (QOL) in part by reducing the pleasure of eating. Olfaction plays an essential role in flavor sensation and palatability. The decreased QOL due to olfactory dysfunction is speculated to result from abnormal neural activities in the olfactory and limbic areas of the brain, as well as peripheral odorant receptor dysfunctions. However, the specific underlying neurobiological mechanisms remain unclear. As the olfactory tubercle (OT) is one of the brain's regions with high expression of endogenous opioids, we hypothesize that the mechanism underlying the decrease in QOL due to olfactory dysfunction involves the reduction of neural activity in the OT and subsequent endogenous opioid release in specialized subregions. In this review, we provide an overview and recent updates on the OT, the endogenous opioid system, and the pleasure systems in the brain and then discuss our hypothesis. To facilitate the effective treatment of olfactory dysfunctions and decreased QOL, elucidation of the neurobiological mechanisms underlying the pleasure of eating through flavor sensation is crucial.
嗅觉功能障碍通过降低进食的愉悦感而降低日常生活质量（QOL）的部分原因。嗅觉在味觉和口感方面起着至关重要的作用。嗅觉功能障碍导致的 QOL 下降，据推测是由于大脑的嗅觉和边缘区域以及外周气味受体功能障碍引起的异常神经活动所致。然而，具体的潜在神经生物学机制尚不清楚。由于嗅结节（OT）是内源性阿片样物质表达水平较高的大脑区域之一，我们假设嗅觉功能障碍导致 QOL 下降的机制涉及 OT 中神经活动的减少，以及随后在专门的亚区域中内源性阿片样物质的释放。在这篇综述中，我们概述并更新了 OT、内源性阿片样物质系统以及大脑中的愉悦系统的最新进展，然后讨论了我们的假设。为了促进嗅觉功能障碍和 QOL 下降的有效治疗，阐明通过味觉感知进食愉悦感的神经生物学机制至关重要。
