Department of Neurology and Danish Headache Centre, Glostrup Research Institute, Glostrup Hospital, University of Copenhagen, Faculty of Health Sciences, 2600 Glostrup, Denmark.
Neuroscience. 2010 Jun 2;167(4):1091-102. doi: 10.1016/j.neuroscience.2010.02.063. Epub 2010 Mar 6.
Large conductance calcium-activated potassium (BK(Ca)) channels are membrane proteins contributing to electrical propagation through neurons. Calcitonin gene-related peptide (CGRP) is a neuropeptide found in the trigeminovascular system (TGVS). Both BK(Ca) channels and CGRP are involved in migraine pathophysiology. Here we study the expression and localization of BK(Ca) channels and CGRP in the rat trigeminal ganglion (TG) and the trigeminal nucleus caudalis (TNC) as these structures are involved in migraine pain. Also the effect of the BK(Ca) channel blocker iberiotoxin and the BK(Ca) channel opener NS11021 on CGRP release from isolated TG and TNC was investigated. By RT-PCR, BK(Ca) channel mRNA was detected in the TG and the TNC. A significant difference in BK(Ca) channel mRNA transcript levels were found using qPCR between the TNC as compared to the TG. The BK(Ca) channel protein was more expressed in the TNC as compared to the TG shown by western blotting. Immunohistochemistry identified BK(Ca) channels in the nerve cell bodies of the TG and the TNC. The beta2- and beta4-subunit proteins were found in the TG and the TNC. They were both more expressed in the TNC as compared to TG shown by western blotting. In isolated TNC, the BK(Ca) channel blocker iberiotoxin induced a concentration-dependent release of CGRP that was attenuated by the BK(Ca) channel opener NS11021. No effect on basal CGRP release was found by NS11021 in isolated TG or TNC or by iberiotoxin in TG. In conclusion, we found both BK(Ca) channel mRNA and protein expression in the TG and the TNC. The BK(Ca) channel protein and the modulatory beta2- and beta4-subunt proteins were more expressed in the TNC than in the TG. Iberiotoxin induced an increase in CGRP release from the TNC that was attenuated by NS11021. Thus, BK(Ca) channels might have a role in trigeminovascular pain transmission.
大电导钙激活钾（BK(Ca)) 通道是一种膜蛋白，有助于神经元的电传播。降钙素基因相关肽（CGRP）是一种在三叉血管系统（TGVS）中发现的神经肽。BK(Ca)) 通道和 CGRP 都参与偏头痛的病理生理学。在这里，我们研究了 BK(Ca)) 通道和 CGRP 在大鼠三叉神经节（TG）和尾状核三叉神经核（TNC）中的表达和定位，因为这些结构参与偏头痛疼痛。还研究了 BK(Ca)) 通道阻断剂 Iberiotoxin 和 BK(Ca)) 通道 opener NS11021 对分离的 TG 和 TNC 中 CGRP 释放的影响。通过 RT-PCR，在 TG 和 TNC 中检测到 BK(Ca)) 通道 mRNA。使用 qPCR 发现 TNC 中 BK(Ca)) 通道 mRNA 转录水平与 TG 相比有显著差异。Western blot 显示，与 TG 相比，TNC 中 BK(Ca)) 通道蛋白表达更高。免疫组织化学鉴定了 TG 和 TNC 中神经细胞体的 BK(Ca)) 通道。在 TG 和 TNC 中发现了 beta2-和 beta4-亚基蛋白。Western blot 显示，与 TG 相比，TNC 中表达更多。在分离的 TNC 中，BK(Ca)) 通道阻断剂 Iberiotoxin 诱导 CGRP 释放呈浓度依赖性，该释放被 BK(Ca)) 通道 opener NS11021 减弱。在分离的 TG 或 TNC 中，NS11021 对基础 CGRP 释放没有影响，在 TG 中，Iberiotoxin 也没有影响。总之，我们在 TG 和 TNC 中发现了 BK(Ca)) 通道的 mRNA 和蛋白表达。与 TG 相比，TNC 中 BK(Ca)) 通道蛋白和调节性 beta2-和 beta4-亚基蛋白表达更高。Iberiotoxin 诱导 TNC 中 CGRP 释放增加，被 NS11021 减弱。因此，BK(Ca)) 通道可能在三叉血管疼痛传递中起作用。
