Regulation of intracellular pH
Regulation of intracellular pH
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DOI：
10.1152/advan.00045.2004
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发表时间：
2004-12-01
影响因子：
2.1
通讯作者：
Boron, WF
中科院分区：
文献类型：
--
作者：
Boron, WF
大多数动物细胞用来调节细胞内pH(pH(I))的方法在概念上与复杂系统调节房屋温度的方式没有太大不同。正如房屋的热容(C)可最大限度地减少由剧烈冷热负荷引起的温度(T)突变一样，电池的缓冲能力(β)可将由急性酸碱负荷引起的pH(I)突变降至最低。然而，增加C(或β)只会最小化T(或pH(I))的变化；它不会消除这些变化，不会使T(或pH(I))恢复正常，也不会移动稳态T(或pH(I))。虽然一所房子可能有一个炉子来提高T，但一个电池通常有一个以上的酸挤压传输器(它输出酸和/或输入碱)来提高pH(I)。空调会降低温度，而电池通常有不止一个载酸转运体来降低pH(I)。正如一所房子可能通过产生热(或冷)输出的逐步增加来对T的逐步降低(或增加)作出反应，细胞对pH(I)的逐步降低(或增加)以排酸(或酸负荷)速率的逐步增加(或减少)做出反应。稳态T(或pH(I))只能响应于慢性冷(或酸)负荷或慢性热(或碱)负荷的变化而改变，例如，由环境T(或pH)的变化或炉子(或酸挤出物)或空调(或酸加载器)的动力学变化所产生。最后，正如温度控制系统可能受益于提供有关冷负荷和热负荷线索的环境传感器一样，至少一些细胞似乎有细胞外二氧化碳或细胞外HCO3--调节酸碱运输的传感器。
The approach that most animal cells employ to regulate intracellular pH (pH(i)) is not too different conceptually from the way a sophisticated system might regulate the temperature of a house. Just as the heat capacity (C) of a house minimizes sudden temperature (T) shifts caused by acute cold and heat loads, the buffering power (beta) of a cell minimizes sudden pH(i) shifts caused by acute acid and alkali loads. However, increasing C (or beta) only minimizes T (or pH(i)) changes; it does not eliminate the changes, return T (or pH(i)) to normal, or shift steady-state T (or pH(i)). Whereas a house may have a furnace to raise T, a cell generally has more than one acid-extruding transporter (which exports acid and/or imports alkali) to raise pH(i). Whereas an air conditioner lowers T, a cell generally has more than one acid-loading transporter to lower pH(i). Just as a house might respond to graded decreases (or increases) in T by producing graded increases in heat (or cold) output, cells respond to graded decreases (or increases) in pH(i) with graded increases (or decreases) in acid-extrusion (or acid-loading) rate. Steady-state T (or pH(i)) can change only in response to a change in chronic cold (or acid) loading or chronic heat (or alkali) loading as produced, for example, by a change in environmental T (or pH) or a change in the kinetics of the furnace (or acid extrudes) or air conditioner (or acid loaders). Finally, just as a temperature-control system might benefit from environmental sensors that provide clues about cold and heat loading, at least some cells seem to have extracellular CO 2 or extracellular HCO3- sensors that modulate acid-base transport.