Role of primary afferents in spinal cord stimulation-induced vasodilation: characterization of fiber types.
Role of primary afferents in spinal cord stimulation-induced vasodilation: characterization of fiber types.
复制标题
初级传入神经在脊髓刺激引起的血管舒张中的作用：纤维类型的表征。
DOI：
10.1016/s0006-8993(02)03740-x
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发表时间：
2003
期刊：
影响因子：
2.9
通讯作者：
Foreman,RobertD
中科院分区：
文献类型：
--
作者：
Tanaka,Satoshi;Barron,KirkW;Chandler,MargaretJ;Linderoth,Bengt;Foreman,RobertD
Selected patients with peripheral vascular disease can be treated with spinal cord stimulation (SCS) to improve blood flow in the limbs. However, the mechanisms producing these effects remain unclear. The present study was designed to investigate if SCS produces cutaneous vasodilation via antidromic activation of the unmyelinated C-fibers and/or the small myelinated fibers. SCS was applied to anesthetized rats with a ball electrode at the L2–L3 spinal level. In Protocol 1, effects of capsaicin were examined. Blood flow changes in the hindpaw induced by SCS were measured in the footpad with laser Doppler flowmeters. Topical application of capsaicin (1%) on the tibial nerve did not affect SCS-induced vasodilation at 30 and 60% of motor threshold (MT). However, the duration of vasodilation induced by SCS at 90% MT and at 10 times MT was significantly reduced after capsaicin application on the tibial nerve. In Protocol 2, antidromic compound action potentials (CAPs) of the tibial nerve were recorded in response to SCS. CAPs of the large and the small myelinated afferent fibers were observed in response to SCS at all intensities. However, even with SCS at ten times MT, CAPs of C-fibers could not be detected in the tibial nerve. In Protocol 3, antidromic CAPs of the dorsal root were measured in response to SCS. Antidromic CAPs of C-fibers in dorsal roots were evoked by SCS at ≥90% of MT. It is concluded that SCS-induced vasodilation at ≤60% of MT may be mediated via only the myelinated fibers, whereas vasodilation at ≥90% of MT may also involve antidromic activation of some unmyelinated C-fibers.
