Pawelczyk J A, Raven P B
Department of Physiology, Texas College of Osteopathic Medicine, Fort Worth 76107.
Am J Physiol. 1989 Nov;257(5 Pt 2):H1389-95. doi: 10.1152/ajpheart.1989.257.5.H1389.
To test the hypothesis that unloading cardiopulmonary receptors improves human carotid baroreceptor responsiveness we measured heart rate (HR) and mean radial artery blood pressure (BP) responses elicited by trains of neck pressure and neck suction from +40 to -65 Torr during graded lower body negative pressure (LBNP) at -5, -10, -15, -20, -35, and -50 Torr in eight healthy men. Gain of the carotid baroreflexes was determined from logistic modeling of the HR [expressed as R-R interval (RRI)] and BP responses to neck pressure and neck suction. Central venous pressure (CVP) decreased progressively from control values of 6.2 +/- 0.6 (SE) Torr to -0.8 +/- 0.1 Torr at -50 Torr LBNP (P less than 0.001). HR changed little from control values of 62.7 +/- 2.1 beat/min to 65.9 +/- 2.8 beat/min at -15 Torr (P = NS), but increased significantly to 80.6 +/- 2.6 beats/min at -50 Torr (P less than 0.001). Maximum gain of the HR and BP stimulus-response curves was linearly and inversely related to decreases in CVP and could be described by the relationships Max RRI gain = -0.694 (CVP) + 11.6 [r2 = 0.94, standard error of estimate (SEE) = 0.45, P less than 0.001] and Max BP gain = -0.0292 (CVP) + 0.391 (r2 = 0.81, SEE = 0.038, P less than 0.001). We suggest that reductions in central venous pressure and/or central blood volume augment both HR and BP carotid baroreflex responses in man by reducing an inhibitory influence from cardiopulmonary receptors.
为了验证卸载心肺感受器可改善人体颈动脉压力感受器反应性这一假设，我们在8名健康男性中，于-5、-10、-15、-20、-35和-50托的分级下体负压（LBNP）期间，测量了由+40至-65托的颈部压力和颈部吸引序列所引发的心率（HR）和桡动脉平均血压（BP）反应。颈动脉压力反射增益通过对HR[以R-R间期（RRI）表示]和对颈部压力及颈部吸引的BP反应进行逻辑建模来确定。中心静脉压（CVP）从对照值6.2±0.6（SE）托在-50托LBNP时逐渐降至-0.8±0.1托（P<0.001）。HR在-15托时从对照值62.7±2.1次/分变化至65.9±2.8次/分，变化不大（P=无显著差异），但在-50托时显著增加至80.6±2.6次/分（P<0.001）。HR和BP刺激-反应曲线的最大增益与CVP的降低呈线性反比关系，可由以下关系描述：最大RRI增益=-0.694（CVP）+11.6[r2=0.94，估计标准误差（SEE）=0.45，P<0.001]，最大BP增益=-0.0292（CVP）+0.391（r2=0.81，SEE=0.038，P<0.001）。我们认为，中心静脉压和/或中心血容量的降低通过减少心肺感受器的抑制性影响，增强了人体HR和BP的颈动脉压力反射反应。
