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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. |
Forma parte de: | 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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