Footedness for scratching itchy eyes in rodents
Footedness for scratching itchy eyes in rodents
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DOI：
10.1098/rspb.2022.1126
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发表时间：
2022-10-26
影响因子：
4.7
通讯作者：
Sakamoto, Hirotaka
中科院分区：
文献类型：
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作者：
Katayama, Yukitoshi;Miura, Ayane;Sakamoto, Hirotaka
与涉及身体瘙痒的神经基础相比，眼睛瘙痒传播的神经基础仍然不清楚。在这里，我们表明在啮齿动物中，三叉神经感觉系统的胃泌素释放肽受体（GRPR）参与了眼睛发痒的传播。有趣的是，我们进一步证明了啮齿动物的左后足和右后足之间的抓挠行为的差异;将组胺滴注到双眼的结膜囊中显示了右足在抓挠运动中的偏侧性。单侧组胺滴注特别诱导同侧感觉通路的神经激活，左眼和右眼滴注后的激活之间没有显着差异。因此，行为偏侧化可能是由于在啮齿动物的右脚偏好。与特定耗尽的三叉神经感觉核尾侧的延髓Grpr表达神经元的基因修饰大鼠表现出更少和更短的组胺诱导的抓挠运动比对照组和消除的footedness。这些结果共同表明，Grpr表达神经元是从眼睛传递瘙痒感觉所必需的，但足部偏好是集中产生的。这些发现可能为脊椎动物偏侧化机制的研究开辟了新的领域，也为难治性青光眼提供了新的潜在治疗方法。
The neural bases of itchy eye transmission remain unclear compared with those involved in body itch. Here, we show in rodents that the gastrin-releasing peptide receptor (GRPR) of the trigeminal sensory system is involved in the transmission of itchy eyes. Interestingly, we further demonstrate a difference in scratching behaviour between the left and right hindfeet in rodents; histamine instillation into the conjunctival sac of both eyes revealed right-foot biased laterality in the scratching movements. Unilateral histamine instillation specifically induced neural activation in the ipsilateral sensory pathway, with no significant difference between the activations following left- and right-eye instillations. Thus, the behavioural laterality is presumably due to right-foot preference in rodents. Genetically modified rats with specific depletion of Grpr-expressing neurons in the trigeminal sensory nucleus caudalis of the medulla oblongata exhibited fewer and shorter histamine-induced scratching movements than controls and eliminated the footedness. These results taken together indicate that the Grpr-expressing neurons are required for the transmission of itch sensation from the eyes, but that foot preference is generated centrally. These findings could open up a new field of research on the mechanisms of the laterality in vertebrates and also offer new potential therapeutic approaches to refractory pruritic eye disorders.