三叉神経

Recent Advances in Trigeminal Nerve Understanding: Anatomy, Pathophysiology, and Emerging Therapeutic Targets

三叉神経は感覚と運動を担う最大の脳神経であり，顔面知覚と咀嚼運動を支配する。本論では三叉神経の解剖・診察法・画像所見を概説し，三叉神経痛，帯状疱疹後神経痛，三叉神経・自律神経性頭痛などの疾患の診断治療を解説する。さらにCGRPやPACAPを中心とした片頭痛治療の新規標的，群発頭痛との関連が注目されるMERTK-Gal-3経路，そして三叉神経節の概日リズムとクロノセラピーの可能性など，最新のトピックスを紹介する。

Abstract

The trigeminal nerve, the largest cranial nerve, has both sensory and motor fibers responsible for facial sensation and mastication. This article reviews the anatomy, clinical examination, and imaging findings of the trigeminal nerve, followed by an overview of its major disorders, including trigeminal neuralgia, painful trigeminal neuropathy attributed to herpes zoster, trigeminal postherpetic neuralgia, and trigeminal autonomic cephalalgia. Recent advances in neuropeptide research have identified calcitonin gene-related peptides (CGRP) and pituitary adenylate cyclase-activating polypeptides (PACAP) as the key molecular targets for trigeminal nerve associated migraine therapy. Moreover, emerging evidence suggests that the MERTK-Galectin-3 signaling pathway may contribute to the pathophysiology of cluster headaches and peripheral sensitization. The discovery of robust circadian rhythms within the trigeminal ganglion further highlights the potential association between headache chronobiology and the timing of drug administration, suggesting a novel concept of chronotherapy in headache management. Collectively, these findings further our understanding of the trigeminal system from anatomical, molecular, and chronobiological perspectives, and may lead to more targeted and time-sensitive therapeutic approaches for primary headache disorders.