Drummond H A, Seagard J L
Zablocki Department of Veterans Affairs Medical Center, Milwaukee, Wisconsin 53226, USA.
Hypertension. 1996 Mar;27(3 Pt 1):442-8. doi: 10.1161/01.hyp.27.3.442.
This study evaluated acute resetting of carotid baroreflex control of arterial blood pressure and renal or thoracic sympathetic nerve activity in thiopental-anesthetized mongrel dogs with the use of a vascularly isolated carotid sinus preparation, the experimental model used previously to characterize acute resetting in carotid baroreceptor afferent fibers. Carotid baroreceptors were conditioned with a pulsatile pressure for 20 minutes at three pressure ranges: low (50 to 75 mm Hg), mid (100 to 125), or high (150 to 175). Blood pressure and nerve activity were recorded in response to slow ramp increases in sinus pressure; nonlinear regression and best-fit analyses were used for determination of curve fit parameters of the blood pressure and nerve activity versus sinus pressure response curves. Carotid sinus pressure thresholds for blood pressure and renal nerve activity responses at all conditioning pressures were significantly different; however, only the pressure threshold for thoracic nerve activity at the low conditioning pressure was significantly different from the responses at other conditioning pressures. Average renal activity resetting (0.506 +/- 0.072) was significantly greater than blood pressure resetting (0.335 +/- 0.046) in the same dogs, and thoracic activity (0.200 +/- 0.057) was not different from blood pressure resetting (0.194 +/- 0.031) in the same dogs. In a previous investigation, our laboratory had demonstrated that type 1 carotid baroreceptors acutely reset at a value of about 0.15. These results indicate that (1) renal and thoracic nerve activities and blood pressure acutely reset to a greater degree than type 1 carotid baroreceptors and that (2) renal activity acutely resets to a greater degree than blood pressure and thoracic nerve activity.
本研究利用血管分离的颈动脉窦制备方法，评估硫喷妥钠麻醉的杂种犬动脉血压的颈动脉压力感受器反射控制以及肾或胸交感神经活动的急性重调定。该实验模型先前用于表征颈动脉压力感受器传入纤维的急性重调定。在三个压力范围对颈动脉压力感受器施加脉动压力20分钟：低（50至75毫米汞柱）、中（100至125）或高（150至175）。记录血压和神经活动对窦压力缓慢斜坡式升高的反应；采用非线性回归和最佳拟合分析来确定血压和神经活动与窦压力反应曲线的曲线拟合参数。在所有调节压力下，血压和肾神经活动反应的颈动脉窦压力阈值均有显著差异；然而，只有低调节压力下胸神经活动的压力阈值与其他调节压力下的反应有显著差异。在同一组犬中，平均肾活动重调定（0.506±0.072）显著大于血压重调定（0.335±0.046），且胸活动（0.200±0.057）与同一组犬的血压重调定（0.194±0.031）无差异。在先前的一项研究中，我们实验室已证明1型颈动脉压力感受器急性重调定的值约为0.15。这些结果表明：（1）肾和胸神经活动以及血压的急性重调定程度大于1型颈动脉压力感受器；（2）肾活动的急性重调定程度大于血压和胸神经活动。
