Chevalier-Cholat A M, Friggi A
J Physiol (Paris). 1976;72(8):971-86.
10Carotid sinus (SIN), aortic (AO) and subclavian (SUB) baroreceptor activities were recorded from intact nerves during experiments using cardiopulmonary bypass in 11 rabbits. These activities (number of impulses/second) were expressed as a percentage of basal activity observed before artificial circulation (AC). The preparation remained in a relative, "stable period" for up to 45 minutes. Then, a progressive decrease occurred in maximal arterial pressure (AP max) in the 11 experiments (fig. 2,4). 20 According to the level of arterial pressure the "stable period", our experiments can be divided into two groups: a) Group I (6 rabbits) with AP max greater than or equal 90 mm Hg; in this group, the correlation coefficients between pressure levels and nervous activities calculated during the period 0-70 min after the onset of AC, were positive (fig. 3) and statistically significant, as we could expect (AO, p less than 0.02; SIN, p less than 0.01; SUB, p less than 0.01). b) Group II (5 rabbits) with AP max less than 90 mm Hg; surprisingly, in this group no positive correlation was found between levels and nervous activities, which were generally very high (fig. 5). 30 Experiments were performed in 18 other rabbits in order to check the nature of the higher activities recorded in group II. These high activities were not of chemoreceptor or efferent origin, and, thus, were thought to be indeed really from baroreceptive fibres. 40 Ten experiments under AC were carried out to test the reactivity of baroreceptors in response to induced increase and decrease of pressure. The responses were qualitatively normal (i.e. an increase of pressure produced an increase in the nervous discharge), but in group II, the operative point was set at a higher level (fig. 6). 50 A possible, time-dependent, shift in the baroreceptor response curve under AC can account for these findings by giving, in some cases the illusion of a negative correlation between baroreceptor activity and arterial pressure (fig. 8). 60 The above mentioned shift in the baroreceptor response curve could be related to a change in sympathetic control of baroreceptors,resulting in a higher activity, and initiating and/or maintaining hypotension.
在11只兔子进行体外循环实验期间，从完整的神经记录了颈动脉窦（SIN）、主动脉（AO）和锁骨下（SUB）压力感受器的活动。这些活动（每秒冲动数）表示为人工循环（AC）前观察到的基础活动的百分比。该标本在长达45分钟的时间内处于相对“稳定期”。然后，在11次实验中，最大动脉压（AP max）逐渐下降（图2,4）。根据动脉压水平和“稳定期”，我们的实验可分为两组：a）第一组（6只兔子），AP max大于或等于90 mmHg；在该组中，AC开始后0 - 70分钟内计算的压力水平与神经活动之间的相关系数为正（图3），且具有统计学意义，正如我们所预期（AO，p小于0.02；SIN，p小于0.01；SUB，p小于0.01）。b）第二组（5只兔子），AP max小于90 mmHg；令人惊讶的是，在该组中未发现压力水平与神经活动之间的正相关，而神经活动通常非常高（图5）。为了检查第二组中记录到的较高活动的性质，对另外18只兔子进行了实验。这些高活动并非化学感受器或传出神经起源，因此，被认为确实来自压力感受纤维。在AC下进行了10次实验，以测试压力感受器对诱导的压力升高和降低的反应性。反应在定性上是正常的（即压力升高导致神经放电增加），但在第二组中，操作点设定在较高水平（图6）。AC下压力感受器反应曲线可能存在的时间依赖性偏移可以解释这些发现，在某些情况下会产生压力感受器活动与动脉压之间负相关的错觉（图8）。上述压力感受器反应曲线的偏移可能与压力感受器交感神经控制的变化有关，导致更高的活动，并引发和/或维持低血压。
