Rapid resetting of aortic baroreceptors in vitro.
Rapid resetting of aortic baroreceptors in vitro.
复制标题
主动脉压力感受器体外快速重置。
DOI：
10.1152/ajpheart.1983.244.5.h672
复制
发表时间：
1983
期刊：
影响因子：
--
通讯作者：
A. Brown
中科院分区：
文献类型：
--
作者：
P. Munch;M. Andresen;A. Brown
动脉压力感受器（BR）的压力反应特性最近显示在平均动脉压（MAP）变化15至20分钟后重置；曲线向MAP变化的方向移动。为了比体外研究更精确地表征这种快速BR重置过程，我们利用Wistar-Kyoto大鼠的体外主动脉弓-主动脉神经制备。压力坡道被用来确定单个BRs暴露于精确控制的调节压力后的放电响应曲线。所有BRs都发生了快速复位，并遵循指数时间过程，时间常数为3至5分钟。复位曲线在1小时内稳定，完全可逆。曲线沿压力轴平行移动，即压力阈值（Pth）改变，斜率和平均渐近流量不变。在长达7小时的实验中，可能有两个以上的MAP步骤，体外快速复位是一个非常一致和可重复的过程。定量地，在40-160 mmHg的MAP范围内，重置幅度（δ Pth/ δ MAP）平均为0.33。因此，体外重置与体内观察到的非常相似，这表明调节压力是重置的主要决定因素，也许是唯一的决定因素。复位发生在阈下map，表明动作电位不是先决条件。也不需要传出神经或激素的影响。
Pressure-response characteristics of arterial baroreceptors (BR) were shown recently to be reset following a 15- to 20-min change in mean arterial pressure (MAP); the curves shifted in the direction of the MAP change. To characterize this rapid BR resetting process more precisely than in vitro studies allow, we utilized an in vitro aortic arch-aortic nerve preparation from Wistar-Kyoto rats. Pressure ramps were used to determine the discharge response curves of single BRs following exposure to precisely controlled conditioning pressures. Rapid resetting occurred in all BRs and followed an exponential time course with a 3- to 5-min time constant. The reset curves were stable for 1 h and were completely reversible. The curves were shifted along the pressure axis in a parallel manner, i.e., pressure threshold (Pth) changed but slope and mean asymptotic discharge were unaltered. In experiments lasting as long as 7 h in which more than two MAP steps were possible, in vitro rapid resetting was a very consistent and reproducible process. Quantitatively, the extent of resetting (delta Pth/delta MAP) averaged 0.33 over an MAP range of 40-160 mmHg. In vitro resetting therefore appears very similar to that observed in vivo, suggesting that the conditioning pressure is the primary, perhaps the sole, determinant of resetting. Resetting occurred at subthreshold MAPs, demonstrating action potentials are not a prerequisite. Efferent neural or hormonal influences are also not required.