去大脑猫肌肉收缩开始时压力感受器反射的变化。

Changes in the baroreceptor reflex at the start of muscle contraction in the decerebrate cat.

McWilliam P N, Yang T, Chen L X

Department of Cardiovascular Studies, University of Leeds.

J Physiol. 1991 May;436:549-58. doi: 10.1113/jphysiol.1991.sp018566.

The action of muscle contraction on the sensitivity of the cardiac vagal component of the baroreceptor reflex was examined in decerebrate cats. 2. The sensitivity of the baroreceptor reflex was expressed as the difference between the maximum prolongation of the R-R interval in response to carotid sinus baroreceptor stimulation and the mean of ten R-R intervals immediately before carotid sinus pressure elevation. 3. Muscle contraction elicited by electrical stimulation of L7 ventral roots (50 Hz) significantly reduced the sensitivity of the baroreceptor reflex by reducing the prolongation of the R-R interval from 269 +/- 31 to 159 +/- 22 ms. 4. Inhibition of the cardiac vagal component of the baroreceptor reflex was seen just 1 s after the onset of contraction and with stimulation frequencies as low as 10 Hz. 5. These results show for the first time that changes in the sensitivity of the baroreceptor reflex during exercise result in part from afferent information originating in the contracting muscles.

在去大脑猫中研究了肌肉收缩对压力感受器反射的心脏迷走神经成分敏感性的作用。2. 压力感受器反射的敏感性表示为对颈动脉窦压力感受器刺激作出反应时R-R间期的最大延长与颈动脉窦压力升高前十个R-R间期平均值之间的差值。3. 通过电刺激L7腹根（50Hz）引发的肌肉收缩显著降低了压力感受器反射的敏感性，使R-R间期的延长从269±31毫秒减少到159±22毫秒。4. 在收缩开始后仅1秒，且刺激频率低至10Hz时，就观察到了压力感受器反射的心脏迷走神经成分受到抑制。5. 这些结果首次表明，运动过程中压力感受器反射敏感性的变化部分源于收缩肌肉传来的传入信息。

Changes in the baroreceptor reflex at the start of muscle contraction in the decerebrate cat.