Intracellular proton mobility and buffering power in cardiac ventricular myocytes from rat, rabbit, and guinea pig.
Intracellular proton mobility and buffering power in cardiac ventricular myocytes from rat, rabbit, and guinea pig.
复制标题
大鼠、兔和豚鼠心室肌细胞的细胞内质子迁移率和缓冲能力。
DOI：
10.1152/ajpheart.00277.2003
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Vaughan-Jones,RichardD
中科院分区：
文献类型：
--
作者：
Zaniboni,Massimiliano;Swietach,Pawel;Rossini,Alessandra;Yamamoto,Taku;Spitzer,KennethW;Vaughan-Jones,RichardD
细胞内 pH (pHi) 是心脏功能的重要调节剂。细胞质内 pH 的空间调节部分取决于细胞内 H+(\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+}\) \end{document})流动性。 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+},{\ 的表观扩散系数}D_{\mathrm{H}}^{\mathrm{app}}\) \end{document}，是在从大鼠、豚鼠和兔子分离的单心室肌细胞中估计的。 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document} 是通过 H+ 扩散到局部的二维模型的最佳拟合预测得出的细胞内 [H+] 的升高，从充满酸的全细胞贴片移液管下游共聚焦（比例半萘霍达氟荧光）记录。 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{CO}_{2}{/}\mathrm{HCO}_{3}^{-}\mathrm{-free}\) \end{document} 条件下， \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document} 在所有三个物种中都相似（平均值：8–12.5 × 10–7cm2/s）比水中的 H+ 低 200 多倍。在豚鼠肌细胞中， \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document} 在存在的情况下增加了 2.5 倍\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{CO}_{2}{/}\mathrm{HCO}_{3}^{-}\) \end{document} 缓冲区，与之前在兔肌细胞中的观察结果一致。 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+}\) \end{document} 心肌细胞中的流动性较低，这一特征可能使它们容易产生pH 梯度响应肌膜酸/碱运输或局部细胞质酸的产生。低 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+}\) \end{document} 移动性很可能是由于细胞质移动和固定缓冲区之间的 H+ 穿梭造成的。通过比较所有三个物种测量的内在细胞内缓冲能力的 pH 依赖性，并将缓冲细分为移动部分和固定部分，探索了这一假设。移动缓冲区的比例将是 \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document} 的主要决定因素。在给定的 pHi 下，这个比例似乎在所有方面都是相似的……
Intracellular pH (pHi) is an important modulator of cardiac function. The spatial regulation of pH within the cytoplasm depends, in part, on intracellular H+(\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+}\) \end{document}) mobility. The apparent diffusion coefficient for \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+},{\ }D_{\mathrm{H}}^{\mathrm{app}}\) \end{document}, was estimated in single ventricular myocytes isolated from the rat, guinea pig, and rabbit. \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document} was derived by best-fitting predictions of a two-dimensional model of H+diffusion to the local rise of intracellular [H+], recorded confocally (ratiometric seminaphthorhodafluor fluorescence) downstream from an acid-filled, whole cell patch pipette. Under \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{CO}_{2}{/}\mathrm{HCO}_{3}^{-}\mathrm{-free}\) \end{document} conditions, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document} was similar in all three species (mean values: 8–12.5 × 10–7cm2/s) and was over 200-fold lower than that for H+in water. In guinea pig myocytes, \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document} was increased 2.5-fold in the presence of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{CO}_{2}{/}\mathrm{HCO}_{3}^{-}\) \end{document} buffer, in agreement with previous observations in rabbit myocytes. \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+}\) \end{document} mobility is therefore low in cardiac cells, a feature that may predispose them to the generation of pHigradients in response to sarcolemmal acid/base transport or local cytoplasmic acid production. Low \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{H}_{\mathrm{i}}^{+}\) \end{document} mobility most likely results from H+shuttling among cytoplasmic mobile and fixed buffers. This hypothesis was explored by comparing the pHidependence of intrinsic, intracellular buffering capacity, measured for all three species, and subdividing buffering into mobile and fixed fractions. The proportion of buffer that is mobile will be the main determinant of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(D_{\mathrm{H}}^{\mathrm{app}}\) \end{document}. At a given pHi, this proportion appeared to be similar in all …