University of Brest, LIEN, F-29200 Brest, France.
Department of Dermatology, Brest University Hospital, Brest, France.
Br J Dermatol. 2023 Feb 10;188(2):176-185. doi: 10.1093/bjd/ljac066.
Sensory neurons innervating the skin are conventionally thought to be the sole transducers of touch, temperature, pain and itch. However, recent studies have shown that keratinocytes - like Merkel cells - act as sensory transducers, whether for innocuous or noxious mechanical, thermal or chemical stimuli, and communicate with intraepidermal free nerve endings via chemical synaptic contacts. This paradigm shift leads to consideration of the whole epidermis as a sensory epithelium. Sensory neurons additionally function as an efferent system. Through the release of neuropeptides in intimate neuroepidermal contact areas, they contribute to epidermal homeostasis and to the pathogenesis of inflammatory skin diseases. To counteract the dogma regarding neurocutaneous interactions, seen exclusively from the perspective of soluble and spreading mediators, this review highlights the essential contribution of the unrecognized anatomical contacts between sensory neurons and epidermal cells (keratinocytes, melanocytes, Langerhans cells and Merkel cells), which take part in the reciprocal dialogue between the skin, nervous system and immune system.
传统上认为，支配皮肤的感觉神经元是触觉、温度、疼痛和瘙痒的唯一传感器。然而，最近的研究表明，角质形成细胞——类似于 Merkel 细胞——作为感觉传感器发挥作用，无论是对无害还是有害的机械、热或化学刺激，并且通过化学突触接触与表皮内游离神经末梢进行通信。这种范式转变导致将整个表皮视为感觉上皮。感觉神经元还作为传出系统发挥作用。通过在亲密的神经表皮接触区域释放神经肽，它们有助于表皮的动态平衡和炎症性皮肤病的发病机制。为了对抗仅从可溶性和扩散性介质的角度来看待神经皮肤相互作用的教条，本综述强调了感觉神经元和表皮细胞（角质形成细胞、黑素细胞、朗格汉斯细胞和 Merkel 细胞）之间未被认识到的解剖接触的重要贡献，这些接触参与了皮肤、神经系统和免疫系统之间的相互对话。
