Kageneck Charlotte, Nixdorf-Bergweiler Barbara E, Messlinger Karl, Fischer Michael Jm
Institute of Physiology and Pathophysiology, University of Erlangen-Nuremberg, Universitaetsstrasse, 91054 Erlangen, Germany.
J Headache Pain. 2014 Feb 8;15(1):7. doi: 10.1186/1129-2377-15-7.
CGRP is contained in a substantial proportion of unmyelinated trigeminal neurons innervating intracranial tissues. Previously, we have described a hemisected rodent scull preparation and later the intact trigeminal ganglion to measure stimulated CGRP release from trigeminal afferents.
Here, we establish a preparation for examining CGRP release from central trigeminal terminals using single fresh slices of the mouse medullary brainstem.
Basal and stimulated amount of CGRP substantially exceeded the detection level. Experiments were designed as matched pairs of at least six brainstem slices per animal. Stimulation with high potassium induced calcium-dependent and reversible CGRP release. Capsaicin stimulation of TRPV1 provoked concentration-dependent CGRP release. The anti-migraine drug naratriptan did not inhibit capsaicin-induced CGRP release from peripheral terminals but inhibited the release from brainstem slices. The glutamate antagonist kynurenate showed a similar pattern of site-specific inhibition of CGRP release.
As observed earlier for other drugs used in the treatment of migraine this indicates that the central terminals in the spinal trigeminal nucleus may be the main site of action. The preparation allows evaluating the trigeminal brainstem as a pharmacological site of action.
降钙素基因相关肽（CGRP）存在于支配颅内组织的大量无髓三叉神经元中。此前，我们描述了一种半切啮齿动物颅骨制备方法，随后又描述了完整三叉神经节，用于测量三叉神经传入纤维受刺激后CGRP的释放。
在此，我们建立了一种使用小鼠延髓脑干新鲜切片来检测三叉神经中枢终末CGRP释放的制备方法。
CGRP的基础释放量和受刺激后的释放量大大超过检测水平。实验设计为每只动物至少六个脑干切片组成的配对组。高钾刺激诱导了钙依赖性且可逆的CGRP释放。辣椒素对瞬时受体电位香草酸亚型1（TRPV1）的刺激引发了浓度依赖性的CGRP释放。抗偏头痛药物那拉曲坦不抑制辣椒素诱导的外周终末CGRP释放，但抑制脑干切片中的释放。谷氨酸拮抗剂犬尿喹啉酸显示出类似的对CGRP释放的位点特异性抑制模式。
正如之前观察到的用于治疗偏头痛的其他药物一样，这表明三叉神经脊束核中的中枢终末可能是主要作用部位。该制备方法可用于评估三叉神经脑干作为一个药理学作用位点。
