Functional characterization of intracellular pH regulators responsible for acid extrusion in human radial artery smooth muscle cells.
Chin J Physiol
; 57(5): 238-48, 2014 Oct 31.
Article
en En
| MEDLINE
| ID: mdl-25241983
ABSTRACT
Intracellular pH (pHi) is a critical factor influencing many important cellular functions. Acid extrusion carriers such as an Naâº/H⺠exchanger (NHE) Naâº/HCO3â» cotransporter (NBC) and monocarboxylate transporters (MCT) can be activated when cells are in an acidic condition (pHi < 7.1). Human radial artery smooth muscle cells (HRASMC) is an important conduit in coronary artery bypass graft surgery. However, such far, the pHi regulators have not been characterized in HRASMCs. We therefore investigated the mechanism of pHi recovery from intracellular acidosis and alkalosis, induced by NH4Cl-prepulse and Na-acetate-prepulse, respectively, using intracellular 2',7'-bis(2-carboxethyl)-5(6)- carboxy-fluorescein (BCECF)-fluorescence in HRASMCs. Cultured HRASMCs were derived from the segments of human radial artery that were obtained from patients undergoing bypass grafting. The resting pHi is 7.22 ± 0.03 and 7.17 ± 0.02 for HEPES- (nominally HCO3â»-free) and CO2/HCO3â»- buffered solution, respectively. In HEPES-buffered solution, a pHi recovery from induced intracellular acidosis could be blocked completely by 30 µM HOE 694 (3-methylsulfonyl-4-piperidinobenzoyl, guanidine hydrochloride) a specific NHE inhibitor, or by removing [Naâº]0. In 3% CO2/HCO3â»-buffered solution, HOE 694 slowed the pHi recovery from the induced intracellular acidosis only, while adding together with DIDS (a specific NBC inhibitor) or removal of [Naâº]0 entirely inhibited the acid extrusion. Moreover, α-cyano-4-hydroxycinnamate (CHC; a specific blocker of MCT) blocked the lactate-induced pHi changes. In conclusion, we demonstrate, for the first time, that 3 different pHi regulators responsible for acid extruding, i.e. NHE and NBC, and MCT, are functionally co-existed in cultured HRASMCs.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Equilibrio Ácido-Base
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Ácidos
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Intercambiadores de Sodio-Hidrógeno
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Transportadores de Ácidos Monocarboxílicos
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Proteínas de Transporte de Catión
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Simportadores
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Simportadores de Sodio-Bicarbonato
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Miocitos del Músculo Liso
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Chin J Physiol
Año:
2014
Tipo del documento:
Article
País de afiliación:
China