Interaction between direct sympathetic and vagus nerve stimulation on heart rate in the isolated rabbit heart
Interaction between direct sympathetic and vagus nerve stimulation on heart rate in the isolated rabbit heart
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DOI：
10.1113/expphysiol.2003.002654
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发表时间：
2004-01-01
影响因子：
2.7
通讯作者：
Ng, GA
中科院分区：
文献类型：
--
作者：
Brack, KE;Coote, JH;Ng, GA
在兔离体心脏模型上研究了迷走神经刺激（VS）和交感神经刺激（SS）对固有心率影响的相互作用。研究了不同频率（2Hz（低）、5Hz（中）、7Hz（高））的背景VS对不同频率（2Hz（低）、5Hz（中）、10Hz（高））的SS变时效应的影响。在相反的方向上重复实验，研究不同水平的背景SS对不同水平的VS的变时效应的影响。背景VS以频率依赖的方式降低稳态时SS的总体正性变时效应，并且在低和中SS期间降低心率增加率。这些结果表明，前和postjunctional机制可能参与交感迷走神经的相互作用对心率。另一方面，VS的变时作用在背景SS存在下增强。迷走神经刺激似乎在对离体心脏的变时作用中比交感神经刺激起主导作用。离体心脏标本是研究交感神经和副交感神经刺激对心功能影响的复杂机制的重要模型。
The interaction between the effects of vagus nerve stimulation (VS) and sympathetic stimulation (SS) on intrinsic heart rate was studied in the novel innervated isolated rabbit heart preparation. The effects of background VS, at different frequencies - 2 Hz (low), 5 Hz (medium), 7 Hz (high) - on the chronotropic effects of different frequencies of SS - 2 Hz (low), 5 Hz (medium), 10 Hz (high) - were studied. The experiments were repeated in the reverse direction studying the effects of different levels of background SS on the chronotropic effects of different levels of VS. Background VS reduced the overall positive chronotropic effect of SS at steady state in a frequency dependent manner and the rate of increase in heart rate during low and medium SS (but not high SS) was slowed in the presence of background VS. These results suggest that pre- and postjunctional mechanisms may be involved in the sympatho-vagal interaction on heart rate. On the other hand, the chronotropic effect of VS was enhanced in the presence of background SS. Vagal stimulation appears to play a dominant role over sympathetic stimulation in chronotropic effects on the isolated heart. The innervated isolated heart preparation is a valuable model to study the complex mechanisms underlying the interaction between sympathetic and parasympathetic stimulation on cardiac function.