Yu Yi, Lundeberg Thomas, Yu Long Chuan
Department of Physiology, College of Life Sciences, Peking University, 100871, Beijing, People's Republic of China.
Regul Pept. 2002 Jan 15;103(1):23-7. doi: 10.1016/s0167-0115(01)00326-3.
The present study was performed to explore the effect of calcitonin gene-related peptide (CGRP) and its antagonist CGRP8-37 on the evoked discharge frequency of wide dynamic range (WDR) neurons in the dorsal horn of the spinal cord in rats. Recording was performed with a multibarrelled glass micropipette and the chemicals were delivered by iontophoresis. The discharge of WDR neurons was evoked by transdermic electrical stimulation applied on the ipsilateral hindpaw. (1) Iontophoretic application of CGRP at an ejection current of 100 nA increased the discharge frequency of WDR neurons significantly. (2) Iontophoretic application of CGRP8-37 at an ejection current of 80 or 160 nA induced significant decreases in the discharge frequency of WDR neurons, but not at 40 nA. (3) Iontophoretic application of CGRP8-37 not only antagonized the CGRP-induced increase in the evoked discharge frequency of WDR neurons but also induced a significant decrease in the evoked discharge frequency of WDR neurons compared to basal levels. The results indicate that CGRP and its receptors play a facilitary role on the transmission and/or modulation of nociceptive information in the dorsal horn of the spinal cord in rats.
本研究旨在探讨降钙素基因相关肽（CGRP）及其拮抗剂CGRP8 - 37对大鼠脊髓背角广动力范围（WDR）神经元诱发放电频率的影响。采用多管玻璃微电极进行记录，通过离子电泳给药。通过对同侧后爪进行经皮电刺激来诱发WDR神经元放电。（1）以100 nA的喷射电流离子电泳施加CGRP可显著增加WDR神经元的放电频率。（2）以80或160 nA的喷射电流离子电泳施加CGRP8 - 37可使WDR神经元的放电频率显著降低，但40 nA时无此作用。（3）离子电泳施加CGRP8 - 37不仅拮抗了CGRP诱导的WDR神经元诱发放电频率增加，而且与基础水平相比，还使WDR神经元的诱发放电频率显著降低。结果表明，CGRP及其受体在大鼠脊髓背角伤害性信息的传递和/或调制中起促进作用。
