Department of Neurology, Glostrup Research Institute, Glostrup Hospital, Faculty of Health Science, University of Copenhagen, Glostrup, Copenhagen, Denmark.
Br J Pharmacol. 2010 Dec;161(8):1885-98. doi: 10.1111/j.1476-5381.2010.01012.x.
Calcitonin gene-related peptide (CGRP) is widely distributed in the trigeminovascular system and released from sensory fibres of the cranial dura mater upon noxious stimulation. Such release may be a mechanism underlying migraine headache. Based on data from guinea pig basilar artery preparations, we have here studied CGRP release and uptake in an organ preparation of the hemisected rat skull.
CGRP release from the cranial dura was quantified by a commercial enzyme-linked immunoassay. CGRP was depleted using repetitive challenges of capsaicin. After incubating the tissue with CGRP for 20 min and extensive washing, another capsaicin challenge was performed. Immunohistochemistry was used to visualize CGRP immunofluorescence in dural nerve fibres.
Capsaicin-induced CGRP release was attenuated by the transient receptor potential vanilloid receptor type I antagonist capsazepine or by Ca(2+)-free solutions. After the CGRP-depleted preparation had been exposed to exogenous CGRP, capsaicin-induced CGRP release was increased compared to the challenge just prior to incubation. CGRP uptake was not influenced by Ca(2+)-free solutions. Olcegepant and CGRP(8-37) (CGRP receptor antagonists) did not affect uptake of CGRP. However, a monoclonal CGRP-binding antibody decreased CGRP uptake significantly. Release of CGRP after incubation was attenuated by Ca(2+)-free solutions and by capsazepine. Immunohistochemical assays indicated a weak trend towards CGRP uptake in rat dura mater.
We have presented evidence for CGRP uptake in nerves and its re-release in rat dura mater. This may have implications for the pathophysiology and treatment of migraine.
降钙素基因相关肽（CGRP）广泛分布于三叉血管系统，在颅脊膜感觉纤维受到有害刺激时释放。这种释放可能是偏头痛头痛的一种机制。基于豚鼠基底动脉制剂的数据，我们在此研究了半切鼠颅骨器官制剂中 CGRP 的释放和摄取。
通过商业酶联免疫吸附试验定量测定颅脊膜 CGRP 的释放。使用辣椒素重复刺激来耗竭 CGRP。在组织孵育 CGRP 20 分钟并进行充分洗涤后，进行另一次辣椒素刺激。使用免疫组织化学来可视化脊膜神经纤维中的 CGRP 免疫荧光。
辣椒素诱导的 CGRP 释放被瞬时受体电位香草酸受体 1 拮抗剂辣椒碱或无钙溶液所减弱。在 CGRP 耗竭的制剂暴露于外源性 CGRP 后，与孵育前的辣椒素刺激相比，CGRP 诱导的 CGRP 释放增加。无钙溶液不影响 CGRP 的摄取。Olcegepant 和 CGRP(8-37)（CGRP 受体拮抗剂）不影响 CGRP 的摄取。然而，一种单克隆 CGRP 结合抗体显著降低了 CGRP 的摄取。孵育后 CGRP 的释放被无钙溶液和辣椒碱所减弱。免疫组织化学检测表明，大鼠脊膜中存在 CGRP 摄取的微弱趋势。
我们提供了 CGRP 在神经中摄取及其在大鼠脊膜中重新释放的证据。这可能对偏头痛的病理生理学和治疗有影响。
