SENSATION OF BREATHLESSNESS
SENSATION OF BREATHLESSNESS
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DOI：
10.1093/oxfordjournals.bmb.a070002
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发表时间：
1963-01-01
影响因子：
6.7
通讯作者：
HOWELL, JBL
中科院分区：
文献类型：
--
作者：
CAMPBELL, EJ;HOWELL, JBL
2.呼吸对机械负荷的客观反应弹性负荷或阈值非弹性负荷加在清醒和麻醉的人的呼吸中(Campbell，Dickinson，Dinnick&Howell，1961；Campbell，Dinnick&Howell，1961)引起吸气肌张力的增加。这种反应在几次呼吸中增加，因此即使呼吸工作负荷显著增加，潮气量也经常保持不变。对动物这种反应机制的进一步分析表明，这是一种反射，这种刺激与吸气肌的缩短程度和它们所产生的张力之间的关系改变有关。反射的途径被证明是通过大脑的(坎贝尔、狄金森和豪厄尔，未发表的工作)。因此，对吸气肌负荷的客观和主观反应似乎都是由类似的刺激引起的，即长度的变化：肌肉的张力关系。这表明了这些反应的共同神经基础。客观反应的受体定位于肌肉或肌腱本身，尽管受体的身份没有直接研究。然而，选择是有限的，唯一两个可能的候选者是肌梭和高尔基肌腱器官。如果肌肉的收缩被增加的负荷所对抗，梭内和梭外纤维的错位就会增加；因此，肌梭可能是提供信息的受体，导致检测增加的吸气负荷和由这种负荷引起的吸气收缩的力量增加。主轴和小(Y)电机系统如何做到这一点已经在其他地方讨论过(Campbell&Howell，1962)。识别一种能够检测张力变化的受体则更为困难。高尔基肌腱器官与肌肉的收缩是串联的，可以发出紧张的信号，但其较高的阈值使其不适合区分与小的附加负荷相关的不同紧张。然而，正如稍后将出现的那样，外周张力受体并不是必不可少的
2. Objective Responses of Breathing to Mechanical Loads Elastic loads, or threshold non-elastic loads, added to the breathing of both conscious and anaesthetized human subjects (Campbell, Dickinson, Dinnick & Howell, 1961; Campbell, Dinnick & Howell, 1961) evoked an increase in inspiratory muscle tension. The response increased over several breaths so that the tidal volume was frequently maintained despite considerable increases in the respiratory work load. Further analysis of the mechanism of this response in animals has shown that it is a reflex and that the stimulus is related to the altered relationship between the degree of shortening of the inspiratory muscles and the tension which they develop. The pathways for the reflex were shown to go through the brain (Campbell, Dickinson and Howell, unpublished work). Thus both the objective and subjective responses to loading of the inspiratory muscles appear to be induced by similar stimuli, ie, alterations in length: tension relationships of the muscles. This suggests a common neural basis for these responses. The receptors for the objective responses were localized to the muscles or tendons themselves, although the identity of the receptors was not studied directly. However, the choice is limited and the only two likely candidates are the muscle spindle and the Golgi tendon organ. If the contraction of a muscle is opposed by an increased load, the misalignment of the intrafusal and the extrafusal fibres is increased; thus the muscle spindle could be the receptor providing the information leading both to the detection of added inspiratory loads and to the increased force of inspiratory contraction caused by such loads. The way the spindle and the small (y) motor-system may do this has been discussed elsewhere (Campbell & Howell, 1962). Identification of a receptor which would detect the changes in tension was more difficult. The Golgi tendon organ, being in series with the contraction of the muscle, is in a position to signal tension, but its high threshold makes it unsuitable for discriminating between the different tensions associated with small added loads. However, as will emerge later, a peripheral tension receptor is not essential