The Role of Intracellular pH Changes in Heat Sensitization by Procaine

1993 ◽  
Vol 133 (1) ◽  
pp. 67 ◽  
Author(s):  
Eric D. Wieder ◽  
Michael H. Fox
Keyword(s):  
Intracellular Ph ◽  
Ph Changes ◽  
Heat Sensitization

scholarly journals The Role of the Primary Cilium in Sensing Extracellular pH

Cells ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 704 ◽  
Author(s):  
Kimberly F. Atkinson ◽  
Rinzhin T. Sherpa ◽  
Surya M. Nauli
Keyword(s):  
Endothelial Cells ◽  
Intracellular Ph ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Extracellular Ph ◽  
Vascular Endothelial ◽  
Wild Type ◽  
Ph Changes ◽  
In Cells

Biosensors on the membrane of the vascular endothelium are responsible for sensing mechanical and chemical signals in the blood. Transduction of these stimuli into intracellular signaling cascades regulate cellular processes including ion transport, gene expression, cell proliferation, and/or cell death. The primary cilium is a well-known biosensor of shear stress but its role in sensing extracellular pH change has never been examined. As a cellular extension into the immediate microenvironment, the cilium could be a prospective sensor for changes in pH and regulator of acid response in cells. We aim to test our hypothesis that the primary cilium plays the role of an acid sensor in cells using vascular endothelial and embryonic fibroblast cells as in vitro models. We measure changes in cellular pH using pH-sensitive 2′,7′-biscarboxyethy1-5,6-carboxyfluorescein acetoxy-methylester (BCECF) fluorescence and mitogen-activated protein kinase (MAPK) activity to quantify responses to both extracellular pH (pHo) and intracellular pH (pHi) changes. Our studies show that changes in pHo affect pHi in both wild-type and cilia-less Tg737 cells and that the kinetics of the pHi response are similar in both cells. Acidic pHo or pHi was observed to change the length of primary cilia in wild-type cells while the cilia in Tg737 remained absent. Vascular endothelial cells respond to acidic pH through activation of ERK1/2 and p38-mediated signaling pathways. The cilia-less Tg737 cells exhibit delayed responsiveness to pHo dependent and independent pHi acidification as depicted in the phosphorylation profile of ERK1/2 and p38. Otherwise, intracellular pH homeostatic response to acidic pHo is similar between wild-type and Tg737 cells, indicating that the primary cilia may not be the sole sensor for physiological pH changes. These endothelial cells respond to pH changes with a predominantly K+-dependent pHi recovery mechanism, regardless of ciliary presence or absence.

scholarly journals The role of intracellular pH in the regulation of cation exchanges in yeast

1972 ◽  
Vol 128 (1) ◽  
pp. 139-146 ◽  
Author(s):  
J. P. Ryan ◽  
H. Ryan
Keyword(s):  
Intracellular Ph ◽  
Extracellular Ph ◽  
K Uptake ◽  
Ph Changes ◽  
Optimum Rate ◽  
Na Efflux

1. When yeast oxidizes propan-2-ol in the presence of KCl no uptake of K+occurs. 2. When propionate is added to suspensions containing propan-2-ol, or if the suspensions are bubbled with CO2, a considerable uptake of K+occurs. 3. Maximum K+uptake occurs at a propionate concentration of 2mm. 4. The addition of 20mm-propionate to the suspension lowers the intracellular pH of the yeast from a resting value in the region of 6.2 to approx. 5.6. 5. When K+uptake is measured in the presence of 20mm-propionate, progressive changes in the rate of K+uptake and intracellular pH occur. The optimum rate of K+uptake occurs at an intracellular pH of 5.70. 6. The effect of both intra- and extra-cellular pH on K+–K+exchange was studied and an optimum rate was found at an extracellular pH of 5.35, the corresponding intracellular pH being 6.44. 7. When a Na+-loaded yeast oxidizes propan-2-ol in the presence of KCl, a steady efflux of Na+and influx of K+occurs. The addition of 10mm-propionate to the suspension markedly inhibited the Na+efflux but only slightly decreased the K+influx. 8. The effect of both extra- and intra-cellular pH on Na+efflux was studied with propan-2-ol and with glucose. The results can be best interpreted in terms of intracellular pH changes, and an optimum was obtained at approx. pH6.40.

scholarly journals Atrial Natriuretic Peptide Effects on Intracellular pH Changes and ROS Production in HEPG2 Cells: Role of p38 MAPK and Phospholipase D

2005 ◽  
Vol 15 (1-4) ◽  
pp. 077-088 ◽  
Author(s):  
Patrizia Baldini ◽  
Paolo De Vito ◽  
Daniela Vismara ◽  
Claudia Bagni ◽  
Francesca Zalfa ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
P38 Mapk ◽  
Intracellular Ph ◽  
Natriuretic Peptide ◽  
Phospholipase D ◽  
Hepg2 Cells ◽  
Ros Production ◽  
Ph Changes ◽  
Atrial Natriuretic

scholarly journals Intracellular pH modulates the availability of vascular L-type Ca2+ channels.

1994 ◽  
Vol 103 (4) ◽  
pp. 647-663 ◽  
Author(s):  
U Klöckner ◽  
G Isenberg
Keyword(s):  
Intracellular Ph ◽  
Single Channel ◽  
Surface Membrane ◽  
Life Time ◽  
Bicarbonate Buffer ◽  
State Changes ◽  
Channel Currents ◽  
Inside Out ◽  
Ca2 Channels

L-type Ca2+ channel currents were recorded from myocytes isolated from bovine pial and porcine coronary arteries to study the influence of changes in intracellular pH (pHi). Whole cell ICa fell when pHi was made more acidic by substituting HEPES/NaOH with CO2/bicarbonate buffer (pHo 7.4, 36 degrees C), and increased when pHi was made more alkaline by addition of 20 mM NH4Cl. Peak ICa was less pHi sensitive than late ICa (170 ms after depolarization to 0 mV). pHi-effects on single Ca2+ channel currents were studied with 110 mM BaCl2 as the charge carrier (22 degrees C, pHo 7.4). In cell-attached patches pHi was changed by extracellular NH4Cl or through the opened cell. In inside-out patches pHi was controlled through the bath. Independent of the method used the following results were obtained: (a) Single channel conductance (24 pS) and life time of the open state were not influenced by pHi (between pHi 6 and 8.4). (b) Alkaline pHi increased and acidic pHi reduced the channel availability (frequency of nonblank sweeps). (c) Alkaline pHi increased and acidic pHi reduced the frequency of late channel re-openings. The effects are discussed in terms of a deprotonation (protonation) of cytosolic binding sites that favor (prevent) the shift of the channels from a sleepy to an available state. Changes of bath pHo mimicked the pHi effects within 20 s, suggesting that protons can rapidly permeate through the surface membrane of vascular smooth muscle cells. The role of pHi in Ca2+ homeostases and vasotonus is discussed.

scholarly journals Cytoplasmic [Ca2+] and intracellular pH in lymphocytes. Role of membrane potential and volume-activated Na+/H+ exchange.

1987 ◽  
Vol 89 (2) ◽  
pp. 185-213 ◽  
Author(s):  
S Grinstein ◽  
S Cohen
Keyword(s):  
Protein Kinase C ◽  
Membrane Potential ◽  
Protein Kinase ◽  
Intracellular Ph ◽  
Enzyme Treatment ◽  
Membrane Hyperpolarization ◽  
Kinase C ◽  
Free Media ◽  
Stimulation Of

The effect of elevating cytoplasmic Ca2+ [( Ca2+]i) on the intracellular pH (pHi) of thymic lymphocytes was investigated. In Na+-containing media, treatment of the cells with ionomycin, a divalent cation ionophore, induced a moderate cytoplasmic alkalinization. In the presence of amiloride or in Na+-free media, an acidification was observed. This acidification is at least partly due to H+ (equivalent) uptake in response to membrane hyperpolarization since: it was enhanced by pretreatment with conductive protonophores, it could be mimicked by valinomycin, and it was decreased by depolarization with K+ or gramicidin. In addition, activation of metabolic H+ production also contributes to the acidification. The alkalinization is due to Na+/H+ exchange inasmuch as it is Na+ dependent, amiloride sensitive, and accompanied by H+ efflux and net Na+ gain. A shift in the pHi dependence underlies the activation of the antiport. The effect of [Ca2+]i on Na+/H+ exchange was not associated with redistribution of protein kinase C and was also observed in cells previously depleted of this enzyme. Treatment with ionomycin induced significant cell shrinking. Prevention of shrinking largely eliminated the activation of the antiport. Moreover, a comparable shrinking produced by hypertonic media also activated the antiport. It is concluded that stimulation of Na+/H+ exchange by elevation of [Ca2+]i is due, at least in part, to cell shrinking and does not require stimulation of protein kinase C.

Evaluation of the role of the DNA surface for enhancing the activity of scaffolded enzymes

2021 ◽  
Vol 57 (32) ◽  
pp. 3925-3928
Author(s):  
Peng Lin ◽  
Huyen Dinh ◽  
Yuki Morita ◽  
Zhengxiao Zhang ◽  
Eiji Nakata ◽  
...  
Keyword(s):  
Ph Changes ◽  
Enhanced Activity ◽  
Local Ph ◽  
Dna Scaffold

Local pH changes on the DNA scaffold surface do not contribute to the enhanced activity of scaffolded enzymes.

scholarly journals Dual Role of CO2/HCO3−Buffer in the Regulation of Intracellular pH of Three-dimensional Tumor Growths

2011 ◽  
Vol 286 (16) ◽  
pp. 13815-13826 ◽  
Author(s):  
Alzbeta Hulikova ◽  
Richard D. Vaughan-Jones ◽  
Pawel Swietach
Keyword(s):  
Intracellular Ph ◽  
Three Dimensional ◽  
Dual Role

Role of Intracellular pH in Mammalian Cell Proliferation

1992 ◽  
Vol 2 (3-4) ◽  
pp. 159-179 ◽  
Author(s):  
R.J. Gillies ◽  
R. Martinez-Zaguilan ◽  
E.P. Peterson ◽  
R. Perona
Keyword(s):  
Cell Proliferation ◽  
Intracellular Ph ◽  
Mammalian Cell
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