健康和均衡的饮食是确保中枢和周围神经系统良好运作的重要因素。视黄醇X受体(RXR)介导的信号传导被认为是传递主要饮食依赖性生理和营养信号的重要机制,例如控制髓鞘形成和多巴胺信号传导。最近,维生素A5/X,主要存在于蔬菜中作为维生素原A5/X,被确定为维生素的新概念,该维生素可作为使RXR介导的信号传导成为可能的营养前体。维生素A5/X的活性形式,9-顺式-13,14-脱氢视黄酸(9CDHRA),诱导RXR激活,从而充当中央开关,使各种异二聚体-RXR信号级联,涉及各种伙伴异二聚体,如脂肪酸和类二十烷酸受体/过氧化物酶体增殖物激活受体(PPAR),胆固醇受体/肝X受体(LXRs),维生素D受体(VDR),和维生素A(1)受体/视黄酸受体(RAR)。因此,维生素A5/X的营养供应可能是实现这种大的激素信号传导途径级联的一般营养依赖性开关,因此对于保证整个生物体的稳态似乎很重要。显示RXR介导的信号传导依赖于维生素A5/X,对在脑中全身或直接介导的有益生理和神经保护功能具有直接作用。总之,通过控制多巴胺信号,淀粉样蛋白β-清除,神经保护和神经炎症,维生素A5/X-RXR-RAR-维生素A(1)信号可能是良好心理健康所必需的“关键因素之一”,健康的大脑老化,以及预防药物成瘾和预防大量的神经系统疾病。同样,维生素A5/X-RXR-与髓鞘形成/再髓鞘形成和吞噬作用/脑清除相关的非RAR依赖性信号传导也将有助于此类调节。在这篇综述中,我们讨论了基本的科学背景,逻辑联系和营养/药理学专家建议的神经系统,特别是考虑到老化的大脑。
A healthy and balanced diet is an important factor to assure a good functioning of the central and peripheral nervous system. Retinoid X receptor (RXR)-mediated signaling was identified as an important mechanism of transmitting major diet-dependent physiological and nutritional signaling such as the control of myelination and dopamine signalling. Recently, vitamin A5/X, mainly present in vegetables as provitamin A5/X, was identified as a new concept of a vitamin which functions as the nutritional precursor for enabling RXR-mediated signaling. The active form of vitamin A5/X, 9-cis-13,14-dehydroretinoic acid (9CDHRA), induces RXR-activation, thereby acting as the central switch for enabling various heterodimer-RXR-signaling cascades involving various partner heterodimers like the fatty acid and eicosanoid receptors/peroxisome proliferator-activated receptors (PPARs), the cholesterol receptors/liver X receptors (LXRs), the vitamin D receptor (VDR), and the vitamin A(1) receptors/retinoic acid receptors (RARs). Thus, nutritional supply of vitamin A5/X might be a general nutritional-dependent switch for enabling this large cascade of hormonal signaling pathways and thus appears important to guarantee an overall organism homeostasis. RXR-mediated signaling was shown to be dependent on vitamin A5/X with direct effects for beneficial physiological and neuro-protective functions mediated systemically or directly in the brain. In summary, through control of dopamine signaling, amyloid β-clearance, neuro-protection and neuro-inflammation, the vitamin A5/X - RXR - RAR - vitamin A(1)-signaling might be \"one of\" or even \"the\" critical factor(s) necessary for good mental health, healthy brain aging, as well as for preventing drug addiction and prevention of a large array of nervous system diseases. Likewise, vitamin A5/X - RXR - non-RAR-dependent signaling relevant for myelination/re-myelination and phagocytosis/brain cleanup will contribute to such regulations too. In this review we discuss the basic scientific background, logical connections and nutritional/pharmacological expert recommendations for the nervous system especially considering the ageing brain.