Fonteriz R I, Sanchez A, Mollinedo F, Collado-Escobar D, García-Sancho J
Departamento de Fisiología y Bioquímica, Facultad de Medicina, Universidad de Valladolid, Spain.
Biochim Biophys Acta. 1991 Jun 7;1093(1):1-6. doi: 10.1016/0167-4889(91)90130-p.
Propionic acid induces a calcium mobilization in human neutrophils which is prevented by pretreatment with phorbol ester or pertussis toxin. The effect is reminiscent of that of chemotactic factors and leukotriene B4 and was attributed to cytoplasmic acidification (Naccache, P.H. et al. (1988) J. Cell. Physiol. 136, 118-124). We show there that other weak acids also induced cytoplasmic alkalinization and calcium mobilization. However, addition of trimethylamine together with propionic acid prevented the cytoplasmic acidification without modifying the calcium mobilization. Propionic acid increased the production of inositol phosphates but this effect was largely prevented by the joint addition of trimethylamine. The ionophores nigericin and monensin can both be forced to produce either cytoplasmic acidification or alkalinization by manipulating the extracellular concentrations of Na+, K+ or H+. Both ionophores produced calcium mobilization in all the cases, irrespective of the direction of the cytoplasmic pH shift. The ionophores were documented to collapse existing pH gradients among the cytoplasm and intracellular compartments. We conclude that the calcium-mobilizing effect of propionic acid and other weak acids is not due to the acidification of the cytoplasm. Our results are consistent, however, with calcium mobilization induced by weak acids and ionophores arising from acidification of an alkaline intracellular compartment.
丙酸可诱导人中性粒细胞中的钙动员，而用佛波酯或百日咳毒素预处理可阻止这种现象。这种效应让人联想到趋化因子和白三烯B4的效应，并且被认为是由于细胞质酸化所致（纳卡什，P.H.等人（1988年）《细胞生理学杂志》136卷，118 - 124页）。我们在那里表明，其他弱酸也能诱导细胞质碱化和钙动员。然而，将三甲胺与丙酸一起添加可阻止细胞质酸化，而不改变钙动员。丙酸增加了肌醇磷酸的产生，但这种效应在很大程度上被同时添加三甲胺所阻止。尼日利亚菌素和莫能菌素这两种离子载体，通过控制细胞外Na +、K +或H +的浓度，都能被迫产生细胞质酸化或碱化。在所有情况下，无论细胞质pH值变化的方向如何，这两种离子载体都能引起钙动员。据记载，这两种离子载体可消除细胞质和细胞内区室之间现有的pH梯度。我们得出结论，丙酸和其他弱酸的钙动员效应并非由于细胞质酸化。然而，我们的结果与弱酸和离子载体引起的钙动员是由碱性细胞内区室酸化所导致的这一观点是一致的。
