Acid-sensing ion and epithelial sodium channels do not contribute to the mechanoreceptor component of the exercise pressor reflex.
Acid-sensing ion and epithelial sodium channels do not contribute to the mechanoreceptor component of the exercise pressor reflex.
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酸敏感离子和上皮钠通道对运动加压反射的机械感受器成分没有贡献。
DOI：
10.1152/ajpheart.00450.2008
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Kaufman,MarcP
中科院分区：
文献类型：
--
作者：
McCord,JenniferL;Hayes,ShawnG;Kaufman,MarcP
阿米洛利，注射到腘动脉，已被报道减弱反射性加压反应的小腿三头肌的静态收缩。在收缩骨骼肌中产生的机械和代谢刺激被认为引起这种效应，其被命名为运动加压反射。阿米洛利阻断酸敏感离子通道和上皮钠通道。然而，阿米洛利被认为是阻断对反射的代谢刺激，因为这种药物已经显示出减弱对注射乳酸到骨骼肌的动脉供应的反射升压反应。然而，阿米洛利也可能阻断引起运动加压反射的机械刺激。反射的机械成分可以通过在收缩的前2-5秒期间测量肾交感神经活动来评估。在这段时间内，由收缩开始产生的突然张力使机械感受器迅速放电，而它对代谢感受器的放电几乎没有影响。因此，我们在去脑猫上观察了经腘动脉注射阿米洛利（0.5 μg/kg）对小腿三头肌静态收缩引起的肾交感神经和升压反应的影响。我们发现，阿米洛利显着衰减的升压和肾交感神经收缩反应，对于后者的变量，衰减开始后10秒开始收缩。我们的研究结果使我们得出这样的结论，酸敏感离子通道和上皮钠通道发挥很少，如果有的话，在唤起运动加压反射的机械组成部分的作用。
Amiloride, injected into the popliteal artery, has been reported to attenuate the reflex pressor response to static contraction of the triceps surae muscles. Both mechanical and metabolic stimuli arising in contracting skeletal muscle are believed to evoke this effect, which has been named the exercise pressor reflex. Amiloride blocks both acid-sensing ion channels, as well as epithelial sodium channels. Nevertheless, amiloride is thought to block the metabolic stimulus to the reflex, because this agent has been shown to attenuate the reflex pressor response to injection of lactic acid into the arterial supply of skeletal muscle. The possibility exists, however, that amiloride may also block mechanical stimuli evoking the exercise pressor reflex. The mechanical component of the reflex can be assessed by measuring renal sympathetic nerve activity during the first 2–5 s of contraction. During this period of time, the sudden tension developed by contraction onset briskly discharges mechanoreceptors, whereas it has little effect on the discharge of metaboreceptors. We, therefore, examined the effect of amiloride (0.5 μg/kg) injected into the popliteal artery on the renal sympathetic and pressor responses to static contraction of the triceps surae muscles in decerebrated cats. We found that amiloride significantly attenuated the pressor and renal sympathetic responses to contraction; for the latter variable, the attenuation started 10 s after the onset of contraction. Our findings lead us to conclude that acid-sensing ion channels and epithelial sodium channels play little, if any, role in evoking the mechanical component of the exercise pressor reflex.