The effect of somatosensory stimulation on the blood flow in the skeletal muscle.

用激光多普勒血流仪研究了体感刺激对麻醉人工呼吸大鼠股二头肌血流的影响。结果：1.电针刺激30只S后爪1.5 mA以上，对隐神经中的III类纤维兴奋最大，而对IV类纤维则为阈值以下，刺激后股二头肌血流略有增加，但差异不显著。这些反应在2 mA或更大的EAS时进一步增强，这是IV组纤维的阈值以上。1.5 mA或更高的EAS也可引起肾血流量下降和升压反应。内脏神经切断后，MBF增加的反应逆转为降低的反应，这种反应被进一步切断腰交感神经所抵消。总之，以足以兴奋III和IV组传入纤维的刺激强度刺激后爪，可以通过反射激活肌肉交感神经活动而引起MBF的反射性下降，尽管这种MBF的下降被内脏交感神经活动反射增加引起的压力反应引起的MBF被动增加所抵消。结果2.反向重复电刺激腰椎第3~5节无髓背根30 S引起MBF增加，这种增加可被局部应用降钙素基因相关肽受体拮抗剂完全阻断。

The effect of somatosensory stimulation on the blood flow in the muscle biceps femurs (MBF) was investigated by laser Doppler flowmetry in anesthetized artificially ventilated rat and we found the following results.Result 1. Electro-acupuncture stimulation (EAS) applied to a hindpaw for 30 s at more than 1.5 mA which excited group III fibers almost maximally and was subthreshold for group IV fibers in saphenous nerve elicited small but significant increases of MBF. These responses were further increased at EAS at 2 mA or more, which was supra threshold for group IV fibers. EAS at 1.5 mA or more also elicited decrease of renal blood flow and presser responses. Following the severance of splanchnic nerves, the increased response of MBF reversed to the decreased response, which was abolished by further severance of lumbar sympathetic nerves. In conclusion, EAS to a hindpaw at a stimulus strength sufficient to excite group III and IV afferent fibers, can produce a reflex decrease in MBF via a reflex activation of muscle sympathetic activity, although this decrease in MBF is overridden by an increase in MBF caused passively by a presser response elicited by a reflex increase in splanchnic sympathetic activity.Result 2. Antidromic repetitive electrical stimulation of unmyelinated dorsal roots at 3rd to 5th lumbar segments for 30 s caused an increase in MBF which was totally abolished by a topical application of a CGRP receptor antagonist.