Effects of altered CSF [H+] on ventilatory responses to exercise in the awake goat.
Effects of altered CSF [H+] on ventilatory responses to exercise in the awake goat.
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改变的脑脊液 [H ] 对清醒山羊运动通气反应的影响。
DOI：
10.1152/jappl.1988.65.2.921
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Dempsey,JA
中科院分区：
文献类型：
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作者：
Smith,CA;Jameson,LC;Dempsey,JA
我们研究了在未麻醉的山羊中，延髓化学感受器的酸碱环境的选择性大变化对运动呼吸过度控制的影响。4只完整的和2只颈动脉体去神经山羊接受脑池灌注明显变化的[HCO-3]模拟脑脊液（CSF）（CSF [H+] = 21-95 neq/l; pH 7.68-7.02），直至达到肺泡通气不足或过度通气的新稳态[动脉PCO 2（PaCO 2）= 31-54 Torr]。当山羊完成两个水平的稳态跑步机行走时，继续灌注[CO2产量（VCO 2）增加2至4倍]。在CSF中酸碱状态正常的情况下，山羊通常从休息到运动（-3 Torr PaCO 2，休息到VCO 2 = 1.1 l/min）轻微过度通气。改变CSF灌注液[H+]改变了静息PaCO 2水平（+6和-4 Torr），但除少数例外情况外，运动期间PaCO 2的调节（Δ PaCO 2/Δ VCO 2）保持相似，无论改变CSF [H+]是否施加新的解释性稳态。因此，对运动的呼吸反应的增益（斜率）（肺泡通气量变化与VCO 2变化的比值）在静息PaCO 2（酸性CSF）降低时必须增加约15%，在静息PaCO 2（碱性CSF）增加时必须减少约9%。CSF [H+]对静息PaCO 2和运动期间Δ PaCO 2/VCO 2的类似作用也发生在两个颈动脉体去神经山羊中。我们的研究结果表明，改变的增益运动的呼吸抑制反应发生在急性改变静息PaCO 2设定点（通过改变CSF [H+]）和运动呼吸过度的主要刺激可以独立于中枢或外周化学感受。
We investigated the effects of selective large changes in the acid-base environment of medullary chemoreceptors on the control of exercise hyperpnea in unanesthetized goats. Four intact and two carotid body-denervated goats underwent cisternal perfusion with mock cerebrospinal fluid (CSF) of markedly varying [HCO-3] (CSF [H+] = 21-95 neq/l; pH 7.68-7.02) until a new steady state of alveolar hypo- or hyperventilation was reached [arterial PCO2 (PaCO2) = 31-54 Torr]. Perfusion continued as the goats completed two levels of steady-state treadmill walking [2 to 4-fold increase in CO2 production (VCO2)]. With normal acid-base status in CSF, goats usually hyperventilated slightly from rest through exercise (-3 Torr PaCO2, rest to VCO2 = 1.1 l/min). Changing CSF perfusate [H+] changed the level of resting PaCO2 (+6 and -4 Torr), but with few exceptions, the regulation of PaCO2 during exercise (delta PaCO2/delta VCO2) remained similar regardless of the new ventilatory steady state imposed by changing CSF [H+]. Thus the gain (slope) of the ventilatory response to exercise (ratio of change in alveolar ventilation to change in VCO2) must have increased approximately 15% with decreased resting PaCO2 (acidic CSF) and decreased approximately 9% with increased resting PaCO2 (alkaline CSF). A similar effect of CSF [H+] on resting PaCO2 and on delta PaCO2/VCO2 during exercise also occurred in two carotid body-denervated goats. Our results show that alteration of the gain of the ventilatory response to exercise occurs on acute alterations in resting PaCO2 set point (via changing CSF [H+]) and that the primary stimuli to exercise hyperpnea can operate independently of central or peripheral chemoreception.