无机磷酸盐和乳酸盐增强了大鼠对酸性刺激的升压反应。
Inorganic phosphate and lactate potentiate the pressor response to acidic stimuli in rats.
机构信息
Heart and Vascular Institute, Penn State College of Medicine, Hershey, PA, 17033, USA.
出版信息
Exp Physiol. 2020 Apr;105(4):613-621. doi: 10.1113/EP088349. Epub 2020 Feb 19.
NEW FINDINGS
What is the central question of this study? What is the contribution of the main acidic compounds accumulated during contractions, namely H , lactic acid and inorganic phosphate, to evoke the metabolic component of the exercise pressor reflex? What is the main finding and its importance? We found that the pressor response to acidic stimuli is driven by the concentration of hydrogen ions and that lactate and inorganic phosphate act as potentiating agents.
ABSTRACT
H ions, lactate and inorganic phosphate are produced by contracting skeletal muscles and evoke, in part, the metabolic component of the exercise pressor reflex. Owing to their disparate dissociation constants (i.e. pK ), the contribution of each acid to the muscle metaboreflex is unclear. This lack of information prompted us to determine the reflex pressor responses to injection of acidic saline, lactate (24 mm) and inorganic phosphate (86 mm) at various values of pH (from 2.66 to 7.5), alone or in combination, into the arterial supply of hindlimb skeletal muscle of decerebrate rats. In particular, we tested the hypothesis that the pressor response to an injection of a combination of lactate and phosphate at an acidic pH is greater than that evoked by injection of either phosphate or lactate alone at the same pH. We found that injection of acidic saline produced a pressor response only at a pH of 2.66 (7 ± 4 mmHg), an effect that was potentiated when the solution contained lactate (50 ± 20 mmHg). At a pH of 6.0, however, this effect was lost. At a pH of 6.0, only the injection of inorganic phosphate produced a significant pressor response (23 ± 12 mmHg). A large potentiating effect was found when lactate was added to the inorganic phosphate solution (39 ± 18 mmHg), an effect that was lost at a pH >7.0. Our findings led to the conclusion that the pressor response to injection of acidic solutions was driven by H ions and that inorganic phosphate and lactate functioned as sensitizing agents.
新发现
这项研究的核心问题是什么？在收缩过程中积累的主要酸性化合物（即 H + 、乳酸和无机磷酸盐）对引发运动加压反射的代谢成分有何贡献？主要发现及其重要性是什么？我们发现，酸性刺激引起的加压反应是由氢离子浓度驱动的，而乳酸和无机磷酸盐则起增强作用。
摘要
H + 、乳酸和无机磷酸盐是由收缩的骨骼肌产生的，并在一定程度上引发运动加压反射的代谢成分。由于它们的离解常数（即 pK ）不同，每种酸对肌肉代谢反射的贡献尚不清楚。由于缺乏这方面的信息，我们确定了向去大脑大鼠后肢骨骼肌动脉供应中单独或组合注射酸性生理盐水、乳酸（24mm）和无机磷酸盐（86mm）时，其反射性加压反应在 pH 值从 2.66 到 7.5 的各种值，以及在相同 pH 值下注射单独的磷酸盐或乳酸时，注射酸性盐水引起的加压反应仅在 pH 值为 2.66（7±4mmHg）时出现，当溶液中含有乳酸时，这种作用增强（50±20mmHg）。然而，在 pH 值为 6.0 时，这种效应消失了。在 pH 值为 6.0 时，只有注射无机磷酸盐会引起显著的加压反应（23±12mmHg）。当将乳酸加入无机磷酸盐溶液中时，会发现一个很大的增强作用（39±18mmHg），这种作用在 pH 值>7.0 时消失。我们的研究结果得出结论，注射酸性溶液引起的加压反应是由 H + 驱动的，而无机磷酸盐和乳酸作为敏化剂起作用。
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