Background: The terminal branches of the trigeminal nerve in meninges are supposed to be the origin site of migraine pain. The main function of these peripheral sensory axons is the initiation and propagation of spikes in the orthodromic direction to the second order neurons in the brainstem. The stimulation of the trigeminal ganglion induces the release of the neuropeptide CGRP in meninges suggesting the antidromic propagation of excitation in these fibers. However, the direct evidence on antidromic spike traveling in meningeal afferents is missing.

Methods: By recording of spikes from peripheral or central parts of the trigeminal nerve in rat meninges, we explored their functional activity and tested the expression of ATP-, serotonin-, and capsaicin-gated receptors in the distal vs. proximal parts of these nerves.

Results: We show the significant antidromic propagation of spontaneous spikes in meningeal nerves which was, however, less intense than the orthodromic nociceptive traffic due to higher number of active fibers in the latter. Application of ATP, serotonin and capsaicin induced a high frequency nociceptive firing in peripheral processes while, in central parts, only ATP and capsaicin were effective. Disconnection of nerve from trigeminal ganglion dramatically reduced the tonic antidromic activity and attenuated the excitatory action of ATP.

Conclusion: Our data indicate the bidirectional nociceptive traffic and dissimilar expression of P2X, 5-HT and TRPV1 receptors in proximal vs. distal parts of meningeal afferents, which is important for understanding the peripheral mechanisms of migraine pain.

背景：脑膜中三叉神经的末端分支被认为是偏头痛的起源。这些周围感觉轴突的主要功能是在正畸方向上向神经干中的二阶神经元发起和传播尖峰。三叉神经节的刺激诱导脑膜中神经肽CGRP的释放，表明这些纤维中兴奋剂的反峰传播。但是，缺少在脑膜传入神经中传播抗峰峰值的直接证据。

方法： 通过记录大鼠脑膜三叉神经周围或中央部分的尖峰，我们探索了它们的功能活性，并测试了这些神经的远端与近端中ATP，血清素和辣椒素门控受体的表达。

结果：我们显示了在脑膜神经中自发性尖峰的显着抗蠕动传播，但是由于后者中活性纤维数量的增加，其强度不如矫正性伤害感受性强。ATP，5-羟色胺和辣椒素的应用在周围过程中引起高频伤害性放电，而在中部，只有ATP和辣椒素有效。三叉神经节神经的断开显着降低了补药的抗线虫活性并减弱了ATP的兴奋作用。

结论： 我们的数据表明，在脑膜传入神经的近端与远端，双向伤害性通信和P2X，5-HT和TRPV1受体的表达不同，这对于理解偏头痛的周围机制很重要。