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Título: Sodium transport systems in human chondrocytes Morphological and functional expression of the Na+,K+-ATPase a and D subunit isoforms in healthy and arthritic chondrocytes
Fecha de publicación: 1999
Editorial: Murcia : F. Hernández
ISSN: 0213-3911
Materias relacionadas: CDU::6 - Ciencias aplicadas::61 - Medicina
Palabras clave: Osteoarthritis
Rheumatoid arthritis
Resumen: The chondrocyte is the cell responsible for the maintenance of the articular cartilage matrix. The negative charges of proteoglycans of the matrix draw cations, principally Na+, into the matrix to balance the negative charge distribution. The Na+,Kf -ATPase is the plasma membrane enzyme that maintains the intracellular Na+ and K+ concentrations. The enzyme is composed of an a and a l3 subunit, so far, 4 a and 3 B isoforms have been identified in mammals. Chondrocytes are sensitive to their ionic and osmotic environment and are capable of adaptive responses to ionic environmental perturbations particularly changes to extracellular [Na+]. In this article we show that human fetal and adult chondrocytes express three a ( a l , a 2 and the neural form of a3) and the three l3 isoforms (131, l32 and 83) of the Na+,K+-ATPase. The presence of multiple Na+,K+-ATPase isoforms in the plasma membrane of chondrocytes suggests a variety of kinetic properties that reflects a cartilage specific and very fine specialization in order to maintain the Na+/K+ gradients. Changes in the ionic and osmotic environment of chondrocytes occur in osteoarthritis and rheumatoid arthritis as result of tissue hydration and proteoglycan loss leading to a fall in tissue Na+ and K+ content. Although the expression levels and cellular distribution of the proteins tested do not vary, we detect changes in p-nitrophenylphosphatase activity "in situ" between control and pathological samples. This change in the sodium pump enzymatic activity suggests that the chondrocyte responds to these cationic environmental changes with a variation of the active isozyme types present in the plasma membrane.
Autor/es principal/es: Trujillo, E.
Alvarez de la Rosa, D.
Mobasheri, A.
Ávila, J.
Gonzalez, T.
Martín Vasallo, P.
Publicado en: Histology and histopathology
URI: http://hdl.handle.net/10201/19239
Tipo de documento: info:eu-repo/semantics/article
Número páginas / Extensión: 12
Derechos: info:eu-repo/semantics/openAccess
Aparece en las colecciones:Vol.14, nº 4 (1999)

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