Speck D F, Revelette W R
J Appl Physiol (1985). 1987 Mar;62(3):941-5. doi: 10.1152/jappl.1987.62.3.941.
Short latency phrenic motor responses to phrenic nerve stimulation were studied in anesthetized, paralyzed cats. Electrical stimulation (0.2 ms, 0.01-10 mA, 2 Hz) of the right C5 phrenic rootlet during inspiration consistently elicited a transient reduction in the phrenic motor discharge. This attenuation occurred bilaterally with an onset latency of 8-12 ms and a duration of 8-30 ms. Section of the ipsilateral C4-C6 dorsal roots abolished the response to stimulation, thereby confirming the involvement of phrenic nerve afferent activity. Stimulation of the left C5 phrenic rootlet or the right thoracic phrenic nerve usually elicited similar inhibitory responses. The difference in onset latency of responses to cervical vs. thoracic phrenic nerve stimulation indicates activation of group III afferents with a peripheral conduction velocity of approximately 10 m/s. A much shorter latency response (5 ms) was evoked ipsilaterally by thoracic phrenic nerve stimulation. Section of either the C5 or C6 dorsal root altered the ipsilateral response so that it resembled the longer latency contralateral response. The low-stimulus threshold and short latency for the ipsilateral response to thoracic phrenic nerve stimulation suggest that it involves larger diameter fibers. Decerebration, decerebellation, and transection of the dorsal columns at C2 do not abolish the inhibitory phrenic-to-phrenic reflex.
在麻醉、麻痹的猫身上研究了膈神经刺激后短潜伏期膈运动反应。在吸气期间对右侧C5膈神经根进行电刺激（0.2毫秒，0.01 - 10毫安，2赫兹）始终会引起膈运动放电的短暂减少。这种衰减双侧发生，起始潜伏期为8 - 12毫秒，持续时间为8 - 30毫秒。切断同侧C4 - C6背根可消除对刺激的反应，从而证实膈神经传入活动的参与。刺激左侧C5膈神经根或右侧胸段膈神经通常会引发类似的抑制反应。对颈段与胸段膈神经刺激反应的起始潜伏期差异表明III类传入神经被激活，其外周传导速度约为10米/秒。胸段膈神经刺激在同侧引发的潜伏期要短得多（5毫秒）。切断C5或C6背根会改变同侧反应，使其类似于潜伏期更长的对侧反应。对胸段膈神经刺激同侧反应的低刺激阈值和短潜伏期表明它涉及直径较大的纤维。去大脑、小脑切除以及在C2水平切断背柱并不会消除膈 - 膈抑制反射。
