Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary.
MTA-SZTE Neuroscience Research Group, University of Szeged, Semmelweis u. 6, Szeged, H 6725, Hungary.
J Headache Pain. 2019 Apr 29;20(1):43. doi: 10.1186/s10194-019-0999-7.
Migraine is a neurovascular primary headache disorder, which causes significant socioeconomic problems worldwide. The pathomechanism of disease is enigmatic, but activation of the trigeminovascular system (TS) appears to be essential during the attack. Migraine research of recent years has focused on neuropeptides, such as calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide 1-38 (PACAP1-38) as potential pathogenic factors and possible therapeutic offensives. The goal of present study was to investigate the simultaneous expression of CGRP and precursor of PACAP1-38 (preproPACAP) in the central region of the TS in a time-dependent manner following TS activation in rats.
The right whisker pad of rats was injected with 50 μl Complete Freund's Adjuvant (CFA) or saline. A mechanical allodynia test was performed with von Frey filaments before and after treatment. Transcardial perfusion of the animals was initiated 24, 48, 72 and 120 h after injection, followed by the dissection of the nucleus trigeminus caudalis (TNC). After preparation, the samples were stored at - 80 °C until further use. The relative optical density of CGRP and preproPACAP was analyzed by Western blot. One-way ANOVA and Kruskal-Wallis followed by Tukey post hoc test were used to evaluate the data. Regression analysis was applied to explore the correlation between neuropeptides expression and hyperalgesia.
Orofacial CFA injection resulted in significant CGRP and preproPACAP release in the TNC 24, 48, 72 and 120 h after the treatment. The level of neuropeptides reached its maximum at 72 h after CFA injection, corresponding to the peak of facial allodynia. Negative, linear correlation was detected between the expression level of neuropeptides and value of mechanonociceptive threshold.
This is the first study which suggests that the expression of CGRP and preproPACAP simultaneously increases in the central region of activated TS and it influences the formation of mechanical hyperalgesia. Our results contribute to a better understanding of migraine pathogenesis and thereby to the development of more effective therapeutic approaches.
偏头痛是一种神经血管原发性头痛疾病，在全球范围内造成了重大的社会经济问题。疾病的发病机制尚不清楚，但三叉神经血管系统 (TS) 的激活似乎在发作期间是必不可少的。近年来，偏头痛研究的重点是降钙素基因相关肽 (CGRP) 和垂体腺苷酸环化酶激活肽 1-38 (PACAP1-38) 等神经肽作为潜在的致病因素和可能的治疗靶点。本研究的目的是在大鼠 TS 激活后，以时间依赖性方式研究 CGRP 和 PACAP1-38 前体 (preproPACAP) 在 TS 中枢区域的同时表达。
用 50μl 完全弗氏佐剂 (CFA) 或生理盐水注射大鼠右侧触须垫。在治疗前后用 von Frey 纤维进行机械性痛觉过敏测试。注射后 24、48、72 和 120 小时，通过心脏灌注动物，然后解剖三叉神经尾核 (TNC)。样本准备后，储存在-80°C，直至进一步使用。用 Western blot 分析 CGRP 和 preproPACAP 的相对光密度。采用单因素方差分析和 Kruskal-Wallis 检验，随后 Tukey 事后检验进行数据分析。回归分析用于探讨神经肽表达与痛觉过敏之间的相关性。
口腔 CFA 注射导致 TNC 中 CGRP 和 preproPACAP 的释放在治疗后 24、48、72 和 120 小时显著增加。神经肽水平在 CFA 注射后 72 小时达到最大值，与面部痛觉过敏的峰值相对应。检测到神经肽表达水平与机械性痛觉阈值之间存在负线性相关。
这是第一项研究表明，CGRP 和 preproPACAP 的表达在激活的 TS 中枢区域同时增加，并影响机械性痛觉过敏的形成。我们的研究结果有助于更好地理解偏头痛的发病机制，从而开发更有效的治疗方法。
