Qingdao International Academician Park, International Institute for Brain Research, Qingdao, China.
CAS Key Laboratory of Brain Connectome and Manipulation, Interdisciplinary Center for Brain Information, The Brain Cognition and Brain Disease Institute, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences Shenzhen Institute of Advanced Technology, Shenzhen, China.
Mol Pain. 2023 Jan-Dec;19:17448069231152101. doi: 10.1177/17448069231152101.
Itch sensation is one of the major sensory experiences of humans and animals. Recent studies using genetic deletion techniques have proposed that gastrin-releasing peptide (GRP) is a key neurotransmitter for itch in the spinal cord. However, these studies are mainly based on behavioral responses and lack direct electrophysiological evidence that GRP indeed mediates itch information between primary afferent fibers and spinal dorsal horn neurons. In this review, we reviewed recent studies using different experimental approaches and proposed that glutamate but not GRP acts as the key neurotransmitter in the primary afferents in the transmission of itch. GRP is more likely to serve as an itch-related neuromodulator. In the cerebral cortex, we propose that the anterior cingulate cortex (ACC) plays a significant role in both itch and pain sensations. Only behavioral measurement of itch (scratching) is not sufficient for itch measurement, since scratching the itching area also produces pleasure. Integrative experimental approaches as well as better behavioral scoring models are needed to help to understand the neuronal mechanism of itch and aid future treatment for patients with pruritic diseases.
瘙痒感是人类和动物的主要感觉体验之一。最近使用基因缺失技术的研究提出，胃泌素释放肽（GRP）是脊髓中瘙痒的关键神经递质。然而，这些研究主要基于行为反应，缺乏 GRP 确实在初级传入纤维和脊髓背角神经元之间介导瘙痒信息的直接电生理证据。在这篇综述中，我们回顾了最近使用不同实验方法的研究，并提出谷氨酸而不是 GRP 作为初级传入纤维中传递瘙痒的关键神经递质。GRP 更可能作为一种与瘙痒相关的神经调质。在大脑皮层中，我们提出前扣带皮层（ACC）在瘙痒和疼痛感觉中都起着重要作用。仅对瘙痒（搔抓）进行行为测量不足以进行瘙痒测量，因为搔抓瘙痒区域也会产生愉悦感。需要综合的实验方法以及更好的行为评分模型来帮助理解瘙痒的神经元机制，并为瘙痒性疾病患者的未来治疗提供帮助。
