pH regulation and buffering power in gastric smooth muscle

Duquette, Robert A.; Wray, Susan

doi:10.1007/s004240100562

Cited by 13 publications

(9 citation statements)

References 37 publications

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“…Myofibroblasts displayed three main acid/base transporters, namely NBC, AE and NHE. These are also the main mechanisms regulating pH i in fibroblasts [2,12,29] and in smooth muscle cells [15]. Thus, AE decreases, whereas, NBC and NHE increase pH i .…”

Section: Discussionmentioning

confidence: 98%

NHE1 activity contributes to migration and is necessary for proliferation of human gastric myofibroblasts

Czepán

Rakonczay

Varró

et al. 2011

Pflugers Arch - Eur J Physiol

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Myofibroblasts play central roles in wound healing, deposition of the extracellular matrix and epithelial function. Their functions depend on migration and proliferation within the subepithelial matrix, which results in accelerated cellular metabolism. Upregulated metabolic pathways generate protons which need to be excreted to maintain intracellular pH (pH(i)). We isolated human gastric myofibroblasts (HGMs) from surgical specimens of five patients. Then we characterized, for the first time, the expression and functional activities of the Na(+)/H(+) exchanger (NHE) isoforms 1, 2 and 3, and the functional activities of the Na(+)/HCO(3)(-) cotransporter (NBC) and the anion exchanger (AE) in cultured HGMs using microfluorimetry, immunocytochemistry, reverse transcription polymerase chain reaction and immunoblot analysis. We showed that NHE1-3, NBC and AE activities are present in HGMs and that NHE1 is the most active of the NHEs. In scratch wound assays we also demonstrated (using the selective NHE inhibitor HOE-642) that carbachol and insulin like growth factor II (IGF-II) partly stimulate migration of HGMs in a NHE1-dependent manner. EdU incorporation assays revealed that IGF-II induces proliferation of HGMs which is inhibited by HOE-642. The results indicate that NHE1 is necessary for IGF-II-induced proliferation response of HGMs. Overall, we have characterized the pH(i) regulatory mechanisms of HGMs. In addition, we demonstrated that NHE1 activity contributes to both IGF-II- and carbachol-stimulated migration and that it is obligatory for IGF-II-induced proliferation of HGMs.

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Section: Discussionmentioning

confidence: 98%

NHE1 activity contributes to migration and is necessary for proliferation of human gastric myofibroblasts

Czepán

Rakonczay

Varró

et al. 2011

Pflugers Arch - Eur J Physiol

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“…Thus, there are at least two factors in the stimulation with the CO2-gas solution, stimulus as an acidified solution and stimulus as a hypoxic solution. In many types of smooth muscle preparations, acidification of the solution results in a relaxation of the preparation and inhibition of agonist-induced contractions (Wray, 1988;Naderali et al, 1997;Duquette and Wray, 2001;Pierce et al, 2003). Hypoxia induces different responses in different gastrointestinal smooth muscle preparations; in the depolarized guinea-pig taenia coli, anoxia produced by replacing O2 with N2 enhances muscle contractions (Nasu et al, 1982;Ishida and Takagi-Ohta, 1996), while N2-gas replaced anoxic solution produced strong inhibition of mechanical activities in smooth muscle preparations isolated from both the human stomach (Hayashi et al, 1986) and the rabbit colon (Pettersson, 1985).…”

Section: Discussionmentioning

confidence: 99%

Carbon dioxide-induced inhibition of mechanical activity in gastrointestinal smooth muscle preparations isolated from the guinea-pig

Fujimoto

Shigemasa

Suzuki

2011

J. Smooth Muscle Res.

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Mechanical responses of smooth muscle elicited by application of CO2-gas bubbled physiological salt solution (CO2-gas solution) were investigated in isolated stomach antrum and colon preparations of the guinea-pig. Circular smooth muscle preparations of both colon and stomach were spontaneously active with periodic generation of phasic contractions. In colonic preparations, the CO2-gas solution produced a biphasic response, with an initial small transient contraction followed by a sustained inhibition of phasic contractions. Removal of the CO2-gas solution allowed a slow recovery of the spontaneous contractions over a period of about 40 min. The recovery developed with a similar time course irrespective of the length of time exposed to CO2-gas solution. The inhibitory responses elicited by CO2-gas solution were not modulated by atropine, N  -nitro-L-arginine or neostigmine. Atropine-sensitive excitatory responses of smooth muscle elicited by transmural nerve stimulation or exogenously applied acetylcholine were attenuated or abolished in the presence of CO2-gas solution. In stomach preparations, the CO2-gas solution elicited a tri-phasic response, with an initial transient relaxation followed by a transient contraction and then a sustained inhibition of the rhythmic contractions. The peak amplitude of the transient contraction was about 2.5 times larger than the spontaneous phasic contractions. The pH of the CO2-gas solution was reduced to about 6. Application of pH 6 solution again produced a tri-phasic response, as was the case for the CO2-gas solution, however the amplitude of the transient contraction was only about 0.4 times that of the spontaneous contractions. The re-appearance of the abolished phasic contraction was quicker with the pH 6 solution (about 1.8 min) than it was for the CO2-gas solution (about 6 min). The inhibitory responses elicited by the CO2-gas solution could be simulated only partly by the acidified solution, and a possible involvement of additional factors in the inhibition elicited by CO2-gas solution was considered.

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“…Changes in pH will affect the proliferation, differentiation and apoptosis of cells [12][13], muscle contraction [14][15], ion transport [16][17], and the stability of the internal environment. Some diseases may arise from abnormal pH such as cystic fibrosis, cancer and neurodegenerative disorders [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Preparation of novel imidazo[1,2-a]indole fluorophore and its application for detecting extreme pH of fungus

Duan

Líu

et al. 2021

Preprint

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A novel pH fluorescent probe imidazo[1,2-a]indole derivative is reported. The probe is highly selective to strong acidic pH (pKa = 3.56) with high sensitivity and a fast response time (within 30 s). It is hardly interfered by ordinary metal ions and has good reversibility under strong acid conditions. The probe transfers charge under different pH conditions, and the response mechanism depends on the change of ICT. It can also be used for imaging in strong acidic Saccharomyces cerevisiae and detection of intracellular H+ as well.

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pH regulation and buffering power in gastric smooth muscle

Cited by 13 publications

References 37 publications

NHE1 activity contributes to migration and is necessary for proliferation of human gastric myofibroblasts

NHE1 activity contributes to migration and is necessary for proliferation of human gastric myofibroblasts

Carbon dioxide-induced inhibition of mechanical activity in gastrointestinal smooth muscle preparations isolated from the guinea-pig

Preparation of novel imidazo[1,2-a]indole fluorophore and its application for detecting extreme pH of fungus

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