Korner P I
Baker Medical Research Institute, Prahran, Victoria, Australia.
Clin Exp Hypertens. 1995 Jan-Feb;17(1-2):425-39. doi: 10.3109/10641969509087082.
Sigmoid logistic function curves provide a powerful means of characterizing the baroreceptor-heart rate reflex. In hypertension the operating range of the reflex is reset in the direction of the elevated resting BP; this can be accounted by rapid resetting of the threshold of the arterial baroreceptors. In addition, there is a deficit in the vagal component of the heart rate (HR) range. Reduction in gain occurs in moderate/severe hypertension, but may be absent in young primary hypertensives. All the changes are reversible, and reversibility of HR range and gain is related to reducing left ventricular hypertrophy or central blood volume rather than to reduction in BP. High plasma angiotensin II can further accentuate the vagal deficit. An input-output model has been developed from comparison of perivascular cuff and drug methods for eliciting the reflex, which place different loads on the heart; the greater load changes simulate many of the alterations in reflex properties observed in hypertension. We conclude that during changes in vasomotor tone in normal animals, about 70% of the drive for the cardiac baroreflex comes from arterial baroreceptors and about 30% from low threshold cardio-pulmonary baroreceptors. In hypertension, the vagal deficit in HR range is due to afferent interactions involving arterial and low and high threshold cardio-pulmonary baroreceptors.
Sigmoid逻辑函数曲线为表征压力感受器 - 心率反射提供了一种有力手段。在高血压中，反射的工作范围朝着静息血压升高的方向重新设定；这可以通过动脉压力感受器阈值的快速重新设定来解释。此外，心率（HR）范围的迷走神经成分存在缺陷。在中度/重度高血压中增益降低，但年轻的原发性高血压患者可能不存在这种情况。所有这些变化都是可逆的，HR范围和增益的可逆性与减轻左心室肥厚或中心血容量有关，而不是与血压降低有关。高血浆血管紧张素II可进一步加重迷走神经缺陷。通过比较用于引发反射的血管周围袖带和药物方法（这两种方法给心脏施加不同负荷）建立了一个输入 - 输出模型；更大的负荷变化模拟了在高血压中观察到的许多反射特性改变。我们得出结论，在正常动物血管运动张力变化期间，心脏压力反射的驱动约70%来自动脉压力感受器，约30%来自低阈值心肺压力感受器。在高血压中，HR范围的迷走神经缺陷是由于涉及动脉以及低阈值和高阈值心肺压力感受器的传入相互作用所致。
