Chiba A, Nakanishi H, Hiruma S, Satou T, Hashimoto S, Chichibu S
Department of Physiology, Kinki University School of Medicine, Osaka-Sayama, Osaka, Japan.
Res Commun Mol Pathol Pharmacol. 1998 Jul;101(1):43-57.
The effects of nembutal and ketamine anesthesia on motor evoked potentials (MEPs) and spinal segment reflex (H-response, F and M waves) were investigated in rats by magnetic stimulation. These potentials were generated by magnetic stimulation of the motor cortex and the spinal cord (L4-L5). After application of nembutal, MEP and H-response decreased in amplitude, eventually disappearing. The amplitudes of F and M waves increased and persisted at the increased levels during anesthesia. The latencies of F and M waves were constant before and after anesthesia. Following ketamine administration, the threshold, latency and amplitude of the magnetically induced MEPs, and M, F and H responses were not influenced systematically. The results suggested that MEPs and H-response depression and/or disappearance due to synaptic site suppression after nembutal anesthesia, and the increase and persistence of increased F and M waves amplitudes were all due to the increasing motoneuron excitability, whereas ketamine did not affect synaptic sites subjected to magnetic stimulation.
通过磁刺激研究了戊巴比妥和氯胺酮麻醉对大鼠运动诱发电位（MEP）和脊髓节段反射（H反射、F波和M波）的影响。这些电位是通过对运动皮层和脊髓（L4-L5）进行磁刺激产生的。给予戊巴比妥后，MEP和H反射的幅度降低，最终消失。F波和M波的幅度增加，并在麻醉期间持续保持在升高水平。F波和M波的潜伏期在麻醉前后保持恒定。给予氯胺酮后，磁诱导MEP的阈值、潜伏期和幅度以及M波、F波和H反射均未受到系统性影响。结果表明，戊巴比妥麻醉后由于突触部位抑制导致MEP和H反射抑制和/或消失，以及F波和M波幅度增加并持续，均是由于运动神经元兴奋性增加，而氯胺酮不影响受到磁刺激的突触部位。
