Berger Albert J, Sebe Joy
Department of Physiology and Biophysics, School of Medicine, University of Washington, Box 357290, Seattle, WA 98195-7290, USA.
Respir Physiol Neurobiol. 2007 Aug 1;157(2-3):206-14. doi: 10.1016/j.resp.2007.01.001. Epub 2007 Jan 11.
The effects of the anesthetic ketamine on properties of inspiratory bursts (I-bursts) in mouse hypoglossal nerve activity were studied in vivo and in vitro. In urethane anesthetized mice we observed rhythmic I-phase activity in only one of eight pups at P9 days. In contrast in older mice rhythmic I-phase hypoglossal activity was almost always observed. Ketamine caused a reduction in I-burst frequency and an increase in peak integrated hypoglossal nerve activity in all three age groups studied (P10-P13, P15-P20 and adult mice). In these mice I-phase oscillations, due to hypoglossal motoneurons firing clusters of action potentials at a particular frequency, were observed in control and after ketamine. Ketamine did not change the frequency of the dominant spectral peak determined from power spectra examined from 0 to 200 Hz. The effects of ketamine were also studied in vitro in the mouse rhythmic medullary slice preparation. Ketamine reduced hypoglossal I-burst frequency and I-burst peak integrated amplitude. Oscillations were observed in I-phase activity, and as in the in vivo studies ketamine did not shift the dominant spectral peak frequency. These results demonstrate that in vivo and in vitro ketamine results in significant changes in I-burst frequency and peak integrated hypoglossal nerve activity, but changes in the oscillation frequency are minimal.
在体内和体外研究了麻醉剂氯胺酮对小鼠舌下神经活动中吸气爆发（I爆发）特性的影响。在氨基甲酸乙酯麻醉的小鼠中，我们在P9天的8只幼崽中仅观察到1只出现节律性I期活动。相比之下，在年龄较大的小鼠中，几乎总能观察到节律性I期舌下活动。氯胺酮使所研究的所有三个年龄组（P10 - P13、P15 - P20和成年小鼠）的I爆发频率降低，舌下神经活动的峰值积分增加。在这些小鼠中，在对照和给予氯胺酮后，均观察到由于舌下运动神经元以特定频率发放动作电位簇而产生的I期振荡。氯胺酮并未改变从0至200 Hz检查的功率谱中确定的主导频谱峰值频率。还在体外小鼠节律性延髓切片制备中研究了氯胺酮的作用。氯胺酮降低了舌下I爆发频率和I爆发峰值积分幅度。观察到I期活动存在振荡，并且与体内研究一样，氯胺酮并未改变主导频谱峰值频率。这些结果表明，在体内和体外，氯胺酮都会导致I爆发频率和舌下神经活动峰值积分发生显著变化，但振荡频率的变化很小。
