脊髓背角某些神经元参与痛觉信息的传递

其中不少神经元对较细直径的躯体和内脏传入发生反应。各种研究证明

脊髓背角神经元的活动持续受到脊髓以上中枢

主要是皮层和脑干的控制。临床实践表明

针刺可以抑制内脏痛。我们在以往的工作中也看到

针刺可以激活包括中缝大核在内的脊髓以上中枢的活动

并由延脑通过下行抑制回路控制内脏传入信息的向上传递和抑制内脏躯体反射(VSR)。组织Unit discharges elicited by stimulation of the A-delta or C afferent fibres in the greater splanchnic nerve were recorded in the thoracic spinal grey matter of unanaesthetized immobilized cats. Electric stimulation of the intercostal nerve in the same segment of the recording site inhibited the evoked response in all 42 units observed. The time course of inhibition ind- uced by a single pulse stimulaion of the intercostal nerve was 350-650msec

suggesting that 2-3 pulses per second would be sufficient for electroacupun- cture of the same segment points. Repetitive electroacupuncture(100 pulses/ sec)at points on the lower limb inhibited the evoked response in 17 out of 23 units. Repetitive stimulation (100 pulses/sec) of the nucleus raphe magnus (NRM) inhibited the evoked response iu 41 out of 51 nuits. In these two ca- ses rpetitive stimuli would be necessary. The evoked responses of the units in the dorsal horn were always inhibited by electroacupuucture or NRM sti- mulatiou. The units in the ventral horn behaved in different ways: sonme were inhibited

some facilitated

and others not influenced by electroacupu- ncture or NRM stimulation.