酸敏感离子通道在中枢化学感受器呼吸调节中的作用

 目的：探讨脑室内注射酸化人工脑脊液（artificial cerebrospinal fluid, aCSF）引起的呼吸效应及酸敏感离子通道（acid sensing ion channels, ASICs）在此过程中的作用。方法：健康成年SD大鼠30只，随机分为aCSF（pH 7.4）对照组、aCSF(pH 6.5)组、ASICs阻断剂阿米洛利（amiloride）对照组、amiloride+aCSF（pH 6.5）组、ASIC1a阻断剂psalmotoxin 1 (PcTx1)对照组及PcTx1+aCSF(pH 6.5)组。通过膈肌肌电记录脑室内注射酸化aCSF后呼吸的变化；通过脑室内先注射阿米洛利和PcTx1再注射酸化aCSF的方法，观察酸敏感离子通道在中枢化学感受器呼吸调节中的作用。结果：脑室内注射酸化aCSF后，呼吸较注射前明显兴奋（P<0.05）；脑室内注射阿米洛利能完全阻断脑室内注射酸化aCSF引起的呼吸兴奋；脑室内注射PcTx1能部分阻断脑室内注射酸化aCSF引起的呼吸兴奋。结论：ASICs是参与中枢化学感受器呼吸调节的关键离子通道，ASIC1a则发挥了部分作用。

Effect of acid sensing ion channels on respiratory regulation by central chemoreceptors

AIM：To investigate the effect of intracerebroventricular (icv) injection of acidulated artificial cerebrospinal fluid (aCSF) on the respiratory reactions and the functions of acid sensing ion channels (ASICs) in this process. METHODS：Healthy adult SD rats (n=30) were divided into aCSF with pH 7.4 control group, aCSF with pH 6.5 group, amiloride control group, amiloride plus aCSF with pH 6.5 group, psalmotoxin 1 (PcTx1) control group and PcTx1 plus aCSF with pH 6.5 group. The electromyogram (EMG) of the diaphragm was monitored to observe the respiratory responses induced by icv injection of acidulated aCSF. The ASICs blockers were also injected into the lateral cerebral ventricle firstly and acidulated aCSF was injected following the ASICs blockers to observe the effect of ASICs on the respiratory regulation by the central chemoreceptor.RESULTS：After icv injection of acidulated aCSF, the respiratory responses of the rats were excited (P<0.05). The respiratory excitation responses disappeared after icv injection of ASICs blocker amiloride. The degree of respiratory excitation was weakened after icv injection of ASIC1a blockers-PcTx1. CONCLUSION：ASICs play a key role in the respiratory regulation by the central chemoreceptor and ASIC1a partly operates in this process.