Why the arterial blood pressure increases during exercise? -A role of muscle mechanoreflex-

实验一为了研究大脑是否是在地上运动开始时产生快速心血管调节所必需的，我们检查了自由移动的去大脑猫在运动过程中的心率（HR），平均动脉血压（MAP）和前肢肱三头肌的积分肌电图（iEMG）。在前丘-乳头体水平进行去脑手术后2 - 4天，动物将自发产生地上运动，支撑体重。在iEMG开始之前，HR立即开始增加，MAP几乎与iEMG开始同时开始升高。在运动过程中，他们的HR和MAP（24 * 3 bpm和22 * 4 mmHg）持续增加。去窦弓神经支配（SAD）对运动开始时（iEMG开始后0-4 s）HR和MAP的突然变化没有影响，而SAD在随后的时间内有相反的影响，HR反应降低（9 * 1b ...更多信息 pm）和MAP反应的增加（30 * 3 mmHg）。这些结果表明，大脑和间脑的吻侧部分在自发地上运动开始时对产生快速的心血管调节不是必需的。动脉压力感受性反射对这种快速调节没有贡献，但在自发运动后期的心血管反应调节中起重要作用。探讨自行车运动中负荷突变对心血管调节的作用。15名健康女性志愿者进行了相同的自行车运动，其中包括一个突然变化的负荷或负荷下降在三个不同的条件下，其中的初步指令有关的负荷变化的口头前自行车运动是没有，真或假。真和假的指令都产生预期的增加HR和MAP观察负荷变化的发病前30秒，而没有指令没有改变它们。在负荷上升或下降开始后，对真实指令的心血管反应比其他指令更快。这些结果表明，初步指导性准备自愿运动可以修改心血管调节突然负荷变化。少

EXPERIMENT I. To examine whether the cerebrum is essential for producing the rapid cardiovascular adjustment at the beginning at overground locomotion, we examined heart rate (HR), mean arterial blood pressure (MAP), and integrated electromyogram (iEMG) of the forelimb triceps brachialis muscle during locomotion in freely-moving decerebrate cats. Two to four days after decerebration surgery performed at the level of precollicular-premammillary body, the animals would spontaneously produce overground locomotion supporting body weight. HR began to increase immediately before the onset of iEMG, and MAP began to rise almost simultaneously with the iEMG onset. Their increases in HR and MAP(24 * 3 bpm and 22 * 4 mmHg) were sustained during locomotion. Sinoaortic denervation (SAD) did not affect the abrupt changes in HR and MAP at the beginning of locomotion (0-4 s from the onset of iEMG), whereas SAD had a contrasting effect during the subsequent period, a decrease in the HR response (9 * 1b … More pm) and an increase in the MAP response (30 * 3 mmHg). These results suggest that the cerebrum an the rostral part of the diencephalon are not essential for producing the rapid cardiovascular adjustment at the beginning of spontaneous overground locomotion. The arterial baroreflex does not contribute this rapid adjustment but play an important role in regulating the cardiovascular responses during the later period of spontaneous locomotion.EXPERIMENT II. To examine the role of a sudden load change on the cardiovascular adjustments during the bicycling exercise. Fifteen healthy female volunteers performed the same bicycling exercise which included one abrupt change of load-up or load-down under three different conditions in which the preliminary instructions about the load change given verbally before the bicycling exercise were no, true or false. The true and false instructions both produced anticipatory increases in HR and MAP observed 30 s before the onset of the load change, whereas no instruction did not alter them. After the onset of load-up or load-down, the cardiovascular responses to true instruction were more rapid than to other instructions. These results suggest that preliminary instructive preparation for voluntary exercise could modify the cardiovascular adjustment to the abrupt load changes. Less