CARDIOVASCULAR-RESPONSES TO STATIC EXERCISE IN MAN - CENTRAL AND REFLEX CONTRIBUTIONS
CARDIOVASCULAR-RESPONSES TO STATIC EXERCISE IN MAN - CENTRAL AND REFLEX CONTRIBUTIONS
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DOI：
10.1113/jphysiol.1990.sp018284
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发表时间：
1990-11-01
影响因子：
5.5
通讯作者：
HOBBS, SF
中科院分区：
文献类型：
--
作者：
GANDEVIA, SC;HOBBS, SF
1.为了评估肌肉化学反射和运动指令的中枢信号对心血管静态运动的贡献，在三种单独的条件下测量血压和心率：（i）等长握柄收缩，（ii）这些收缩产生的代谢物在收缩肌肉内的截留（化学反射效应），和（iii）在三个水平的努力（命令效应）的急性瘫痪肌肉的尝试收缩。2.当收缩停止时，在循环阻断期间评估化学感受器反射。通过在血压计袖带远端局部输注木质素，使其膨胀至高于收缩压，从而产生麻痹。3.血压和心率在33%和50%最大随意力量的等长收缩期间（分别为120和75秒）逐渐增加。在闭塞期间的肌肉化学反射也增加了血压的收缩时间成比例，但没有增加心率。在尝试收缩瘫痪的肌肉在三个测量水平的运动命令，血压和心率增加，但只有心率与命令的水平分级。4.肌肉化学反射的心血管反应模式（如心率和血压变化的比率所示）不同于等长收缩和单独的运动命令。收缩和中等强度但不高强度的运动指令的模式是相似的。5.这些数据表明，中等强度的静态收缩的心血管反应可以主要由运动指令产生，但运动指令和肌肉化学反射有助于心血管反应在较高强度的静态运动。当单独研究时，中枢运动指令和肌肉化学反射不会产生相同的循环反应模式。
1. To assess the contributions of muscle chemoreflexes and central signals of motor command to cardiovascular to static exercise, blood pressure and heart rate were measured during three separate conditions: (i) isometric handgrip contractions, (ii) entrapment of metabolities produced by these contractions within the contracting muscles (chemoreflex effect), and (iii) attempted contractions of acutely paralysed muscles at three levels of effort (command effect). 2. The chemoreflex was assessed during circulatory occlusion applied as the contraction ceased. Paralysis was produced by local infusion of lignocaine distal to a sphygmomanometer cuff inflated above systolic pressure. 3. Blood pressure and heart rate increased progressively during isometric contraction of 33 and 50% maximal voluntary strength (for 120 and 75 s respectively). Muscle chemoreflexes during occlusion also increased blood pressure in proportion to the duration of contraction but did not increase heart rate. During attempted contraction of paralysed muscles at three measured levels of motor command, blood pressure and heart rate increased, but only heart rate was graded with the level of command. 4. The pattern of cardiovascular response for the muscle chemoreflex (as indicated by the ratio of the changes in heart rate and blood pressure) differed from that for isometric contractions and for motor commands in isolation. The pattern for contractions and for moderate but not high intensities of motor command was similar. 5. These data suggest that cardiovascular responses to moderate intensities of static contraction can be produced primarily by motor command, but that both motor command and muscle chemoreflexes contribute to cardiovascular responses at higher intensities of static exercise. When studied in isolation, central motor command and muscle chemoreflexes do not produce the same pattern of circulatory responses.