Physiological and neurochemical adaptations following abrupt termination of chronic hypercapnia in goats.
Physiological and neurochemical adaptations following abrupt termination of chronic hypercapnia in goats.
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山羊慢性高碳酸血症突然终止后的生理和神经化学适应。
DOI：
10.1152/japplphysiol.00909.2020
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Forster,HubertV
中科院分区：
文献类型：
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作者：
Buchholz,KirstynJ;Burgraff,NicholasJ;Neumueller,SuzanneE;Hodges,MatthewRobert;Pan,LawrenceG;Forster,HubertV
慢性高碳酸血症（CH）是呼吸系统疾病如慢性阻塞性肺病的标志。在这些患者中，机械通气通常用于恢复正常的血气稳态。然而，鲜为人知的是，关于生理变化和神经可塑性的生理控制网络终止后CH。利用我们的山羊模型增加吸入CO2-诱导CH，我们确定是否终止CH elelaborate时间依赖性的生理和神经化学变化脑干内的生理控制网站。30天CH增加（+15 mmHg）和稳态通气（SS V至今i;对照组的283%）。在终止CH后24 h内，SS V至今i、血气、动脉[H+]和大多数生理测量恢复至对照。但急性呼吸性化学反射（ΔV ~ i/Δ[H+]）大于对照组，测量的SS V ~ i超过动脉[H+]和ΔV ~ i/Δ[H+]预测的通气量。可能导致这些差异的是孤束核中兴奋性神经调质5-羟色胺和去甲肾上腺素的增加，这与高碳酸血症24小时和30天时观察到的最小变化形成对比。同样，有微小的变化，发现在神经炎症和谷氨酸受体依赖性神经可塑性的标志物终止CH，这是以前增加后24小时的高碳酸血症。因此，在CH终止后：1）排泄、肾和其他生理功能迅速恢复控制;2）排泄控制网络内的神经可塑性可能导致测量的通气量与预测的通气量之间的差异以及急性排泄[H+]化学反射的升高;和3）神经可塑性从根本上不同于对CH的适应。NEW & NOTEWORTH在健康成年山羊中，稳态通气和大多数生理测量在慢性高碳酸血症（CH）终止后24小时内恢复到控制。然而，急性[H+]化学反射增加，测量的通气量超过预测的通气量。在24小时的恢复，兴奋性神经调质高于控制，但其他测量的神经可塑性的标志物从控制不变。我们的数据表明，CH elephants持久的生理和神经化学变化，长达24小时后终止CH。
Chronic hypercapnia (CH) is a hallmark of respiratory diseases such as chronic obstructive pulmonary disease. In such patients, mechanical ventilation is often used to restore normal blood-gas homeostasis. However, little is known regarding physiological changes and neuroplasticity within physiological control networks after termination of CH. Utilizing our goat model of increased inspired CO2-induced CH, we determined whether termination of CH elicits time-dependent physiological and neurochemical changes within brain stem sites of physiological control. Thirty days of CH increased(+15 mmHg) and steady-state ventilation (SS V̇i; 283% of control). Within 24 h after terminating CH, SS V̇i, blood gases, arterial [H+], and most physiological measurements returned to control. However, the acute ventilatory chemoreflex (ΔV̇i/Δ[H+]) was greater than control, and measured SS V̇iexceeded ventilation predicted by arterial [H+] and ΔV̇i/Δ[H+]. Potentially contributing to these differences were increased excitatory neuromodulators serotonin and norepinephrine in the nucleus tractus solitarius, which contrasts with minimal changes observed at 24 h and 30 days of hypercapnia. Similarly, there were minimal changes found in markers of neuroinflammation and glutamate receptor-dependent neuroplasticity upon termination of CH, which were previously increased following 24 h of hypercapnia. Thus, following termination of CH:1) ventilatory, renal, and other physiological functions rapidly return to control;2) neuroplasticity within the ventilatory control network may contribute to the difference between measured vs. predicted ventilation and the elevation in the acute ventilatory [H+] chemoreflex; and3) neuroplasticity is fundamentally distinct from acclimatization to CH.NEW & NOTEWORTHYIn healthy adult goats, steady-state ventilation and most physiological measures return to control within 24 h after termination of chronic hypercapnia (CH). However, the acute [H+] chemoreflex is increased, and measured ventilation exceeds predicted ventilation. At 24 h of recovery, excitatory neuromodulators are above control, but other measured markers of neuroplasticity are unchanged from control. Our data suggest that CH elicits persistent physiological and neurochemical changes for up to 24 h after termination of CH.