Voltage-gated calcium channels may be involved in the regulation of the mechanosensitivity of slowly conducting knee joint afferents in rat
Voltage-gated calcium channels may be involved in the regulation of the mechanosensitivity of slowly conducting knee joint afferents in rat
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DOI：
10.1007/s00221-003-1465-x
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发表时间：
2003-06-01
影响因子：
2
通讯作者：
Heppelmann, B
中科院分区：
文献类型：
--
作者：
Just, S;Heppelmann, B
电压门控性Ca ~（2+）通道在伤害性信息的中枢处理中起重要作用。最近，它已被证明，L-和N-型电压门控Ca 2+通道也存在于肽能，精细传入神经纤维在膝关节囊。因此，L型（维拉帕米）或N型（ω-芋螺毒素GVIA）钙通道的特异性阻断剂对缓慢传导传入的机械敏感性的影响在大鼠膝关节中进行了测试。局部应用100 μ M维拉帕米到感受野减少膝关节旋转的平均反应为67 +/- 8%（SEM，n = 12），获得了一个向外旋转的扭矩为10 mNm以上的机械阈值，并与控制运动相比。在存在50 μ M ω-芋螺毒素GVIA的情况下，平均响应降低至44 +/-5%（n = 12），在其它强度的旋转期间也观察到这种降低。同时应用两种物质进一步将反应降低至25 +/- 11%（n = 6）。在另外的实验中，它表明，L-和N-型电压门控钙通道不影响机械兴奋性的活动依赖性的变化。总之，本研究的数据表明，电压门控性Ca 2+通道也可能参与调节伤害性神经纤维末梢的机械敏感性。
Voltage-gated Ca2+ channels play an important role in the central processing of nociceptive information. Recently, it has been shown that L- and N-type voltage-gated Ca2+ channels are also present on peptidergic, fine afferent nerve fibers in the knee joint capsule. Therefore, the influence of specific blockers for L-type (verapamil) or N-type (omega-conotoxin GVIA) Ca2+ channels on the mechanosensitivity of slowly conducting afferents was tested in the rat knee joint. Topical application of 100 muM verapamil onto the receptive field reduced the mean response to knee joint rotation to 67 +/- 8% (SEM, n = 12), obtained by outward rotations with a torque of 10 mNm above the mechanical threshold and compared with control movements. In the presence of 50 muM omega-conotoxin GVIA, the mean response decreased to 44 +/- 5% (n = 12), a reduction that was also observed during rotations of other intensities. Simultaneous application of both substances further reduced the response to 25 +/- 11% (n = 6). In additional experiments it was shown that L- and N-type voltage-gated Ca2+ channels do not influence activity-dependent changes of the mechanical excitability. In conclusion, the data of the present study indicate that voltage-gated Ca2+ channels may also be involved in the regulation of the mechanosensitivity of nociceptive nerve fiber endings.