Proton-sensing G-protein-coupled receptors (GPCRs; OGR1, GPR4, G2A, TDAG8), with full activation at pH 6.4 ∼ 6.8, are important to pH homeostasis, immune responses and acid-induced pain. Although G2A mediates the G13-Rho pathway in response to acid, whether G2A activates Gs, Gi or Gq proteins remains debated. In this study, we examined the response of this fluorescence protein-tagged OGR1 family to acid stimulation in HEK293T cells. G2A did not generate detectable intracellular calcium or cAMP signals or show apparent receptor redistribution with moderate acid (pH ≥ 6.0) stimulation but reduced cAMP accumulation under strong acid stimulation (pH ≤ 5.5). Surprisingly, coexpression of OGR1- and G2A-enhanced proton sensitivity and proton-induced calcium signals. This alteration is attributed to oligomerization of OGR1 and G2A. The oligomeric potential locates receptors at a specific site, which leads to enhanced proton-induced calcium signals through channels.
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http://dx.doi.org/10.3109/10799893.2016.1155064 | DOI Listing |
Exp Mol Med
November 2024
Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon, 21999, Republic of Korea.
Hormonal regulation during food ingestion and its association with pain prompted the investigation of the impact of glucagon-like peptide-1 (GLP-1) on transient receptor potential vanilloid 1 (TRPV1). Both endogenous and synthetic GLP-1, as well as a GLP-1R antagonist, exendin 9-39, reduced heat sensitivity in naïve mice. GLP-1-derived peptides (liraglutide, exendin-4, and exendin 9-39) effectively inhibited capsaicin (CAP)-induced currents and calcium responses in cultured sensory neurons and TRPV1-expressing cell lines.
View Article and Find Full Text PDFHormonal regulation during food ingestion and its association with pain prompted the investigation of the impact of glucagon-like peptide-1 (GLP-1) on the transient receptor potential vanilloid 1 (TRPV1). Both endogenous and synthetic GLP-1 and an antagonist of GLP-1, exendin 9-39, reduced heat sensitivity in naïve mice. GLP-1-derived peptides (liraglutide, exendin-4, and exendin 9-39) effectively inhibited capsaicin (CAP)-induced currents and calcium responses in cultured sensory neurons and TRPV1-expressing cell lines.
View Article and Find Full Text PDFScience
December 2023
Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Biosciences, Biocenter, Würzburg University, Julius-von-Sachs-Platz 2, D-97082 Würzburg, Germany.
Although there has been long-standing recognition that stimuli-induced cytosolic pH alterations coincide with changes in calcium ion (Ca) levels, the interdependence between protons (H) and Ca remains poorly understood. We addressed this topic using the light-gated channelrhodopsin KCR2 from the pseudofungus , which operates as a H conductive, Ca impermeable ion channel on the plasma membrane of plant cells. Light activation of KCR2 in guard cells evokes a transient cytoplasmic acidification that sparks Ca release from the endoplasmic reticulum.
View Article and Find Full Text PDFDent Mater J
August 2023
Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry.
This study evaluated the effect of tricalcium phosphate-containing fluoride varnish on the prevention of root caries using an in-air micro-proton induced X-ray/gamma-ray emission system and microcomputed tomography. Either fluoride varnish (FV) or tricalcium phosphate-containing fluoride varnish (WV) was applied to root dentin, whereas dentin without varnish were considered controls. After immersion in saline, dentin sections were prepared, and concentration of fluoride ion was measured.
View Article and Find Full Text PDFJ Funct Biomater
November 2022
Division of Clinical Cariology and Endodontology, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, Tobetsu 061-0293, Japan.
Several desensitizers routinely used clinically for dentin hypersensitivity are expected to inhibit demineralization. This study aimed to evaluate the effectiveness of sealing materials in inhibiting demineralization and increasing fluorine (F) uptake by acid-treated root surfaces. Five noncarious extracted human teeth were used to produce specimens.
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