IBCN   20355
INSTITUTO DE BIOLOGIA CELULAR Y NEUROCIENCIA "PROFESOR EDUARDO DE ROBERTIS"
Unidad Ejecutora - UE
artículos
Título:
Neurotensin decreases high affinity [3H]-ouabain binding to cerebral cortex membranes
Autor/es:
C. G. ROSIN; M. G. L¨®PEZ ORDIERES; G. RODRÍGUEZ DE LORES ARNAIZ
Revista:
REGULATORY PEPTIDES
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2011 vol. 172 p. 35 - 40
ISSN:
0167-0115
Resumen:
Previous work from this laboratory showed the ability of neurotensin to inhibit synaptosomal membrane Na+, K+-ATPase activity, the effect being blocked by SR 48692, a non-peptidic antagonist for high affinity neurotensin receptor (NTS1) [L¨®pez Ordieres and Rodr¨ªguez de Lores Arnaiz 2000; 2001]. To further study neurotensin interaction with Na+, K+-ATPase, peptide effect on high affinity [3H]-ouabain binding was studied in cerebral cortex membranes. It was observed that neurotensin modified binding in a dose-dependent manner, leading to 80 % decrease with 1 x 10-4 M concentration. On the other hand, the single addition of 1 x 10-6 M, 1 x 10-5 M and 1 x 10-4 M SR 48692 (Sanofi-Aventis, U.S., Inc.) decreased [3H]-ouabain binding (in %) to 87 ¡À 16; 74 ¡À 16 and 34 ¡À 17, respectively. Simultaneous addition of neurotensin and SR 48692 led to additive or synergic effects. Partial NTS2 agonist levocabastine inhibited [3H]-ouabain binding likewise. Saturation assays followed by Scatchard analyses showed that neurotensin increased Kd value whereas failed to modify Bmax value, indicating a competitive type interaction of the peptide at Na+, K+-ATPase ouabain site. At variance, SR 48692 decreased Bmax value whereas it did not modify Kd value. [3H]-ouabain binding was also studied in cerebral cortex membranes obtained from rats injected i. p. 30 min earlier with 100 ¦Ìg and 250 ¦Ìg / kg SR 48692. It was observed that the 250 ¦Ìg / kg SR 48692 dose led to 19% decrease in basal [3H]-ouabain binding. After SR 48692 treatments, addition of 1 x 10-6 M led to additive or synergic effect. Results suggested that [3H]-ouabain binding inhibition by neurotensin hardly involves NTS1 receptor.