Zhong S, Gebber G L, Zhou S Y, Barman S M
Departments of Pharmacology/Toxicology and Physiology, Michigan State University, East Lansing, Michigan 48824, USA.
Am J Physiol. 1998 Aug;275(2):H331-40. doi: 10.1152/ajpheart.1998.275.2.H331.
We used bispectral analysis to characterize the nonlinear interactions of the respiratory-related (RR), cardiac-related (CR), or 10-Hz rhythms in sympathetic nerve discharge (SND) of urethan-anesthetized cats. Bispectral analysis investigates relationships among frequency triples in the same signal (inferior cardiac postganglionic SND) where the third frequency is the sum of the other two due to quadratic nonlinear coupling. Coupling of the RR and CR rhythms leading to the generation of new components (i.e., modulated frequencies) in SND occurred in 84% of the total cases, whereas the incidence was 71% for the RR and 10-Hz rhythms. The occurrence of such nonlinear interactions implies that the RR, CR, and 10-Hz rhythms are carried to common targets by the same postganglionic sympathetic neurons. Furthermore, we suggest that nonlinear interactions leading to the generation of new frequencies in SND may affect end-organ function beyond the level expected in simple cases of linear superposition of the primary rhythms. This suggestion is supported by our observation that strong coupling of the RR and CR rhythms resulted in appreciable power at the modulated frequencies.
我们采用双谱分析来表征在乌拉坦麻醉猫的交感神经放电（SND）中，与呼吸相关（RR）、与心脏相关（CR）或10赫兹节律的非线性相互作用。双谱分析研究同一信号（心脏节后下神经节SND）中频率三元组之间的关系，其中第三个频率是由于二次非线性耦合而等于其他两个频率之和。RR和CR节律耦合导致SND中产生新成分（即调制频率）的情况在所有病例中占84%，而RR和10赫兹节律的发生率为71%。这种非线性相互作用的发生意味着RR、CR和10赫兹节律由同一节后交感神经元传导至共同靶点。此外，我们认为导致SND中产生新频率的非线性相互作用可能会影响终末器官功能，其影响程度超出了主要节律简单线性叠加情况下预期的水平。我们观察到RR和CR节律的强耦合在调制频率处产生了可观的功率，这一观察结果支持了这一观点。
