HIGH AFFINITY [3H]-OUABAIN BINDING TO CEREBRAL CORTEX MEMBRANES IS DECREASED BY PEPTIDE NEUROTENSIN.

G. RODRÍGUEZ DE LORES ARNAIZ; C. ROSIN; M.G. LÓPEZ ORDIERES

Charleston, Carolina sel Sur, EE.UU.

Congreso; XXXX Congreso de la Sociedad Americana de Neuroquímica (ASN); 2009

Sociedad Americana de Neuroquímica (ASN)

HIGH AFFINITY [³H]-OUABAIN BINDING TO CEREBRAL CORTEX MEMBRANES IS DECREASED BY PEPTIDE NEUROTENSIN Rodríguez de Lores Arnaiz, G. Rosin C., López Ordieres, M.G., Inst Biol Cel y Neuroc “Prof. E. De Robertis”, Fac Med, and Cátedra de Farmacol, Fac Farm y Bioq, UBA. Paraguay 2155, 1121-Buenos Aires, Argentina. E-mail: grodrig@f fyb.uba.ar It has been shown that neurotensin inhibits the activity of synaptosomal membrane Na/K-ATPase, an effect blocked by SR 48692 (SANOFI-AVENTIS, US INC), antagonist for high affinity neurotensin receptor (NTS1). Herein neurotensin effect on high affinity [3H]-ouabain binding was studied. It was observed a dose-dependent decrease, with the following values (% vs control): 89 ± 12; 70 ± 7 and 22 ± 10 (n=3-8) at 10-6M, 10-5M and 10-4 M peptide concentration, respectively. SR 48692 at 10^-6 M, 10^-5M and 10^-4M decreased [³H]-ouabain binding (in %) to 87 ± 16; 74 ± 16 and 34 ± 17 (n = 3-8), respectively. Experiments carried out in the simultaneous presence of neurotensin and SR 48692 at 10^-6M and 10^-5M concentration, respectively indicated synergic or additive effect on [³H]-ouabain binding. Previous administration of SR 48692 (100 or 250 microgram/kg, ip, 30 min) failed to modify [³H]-ouabain binding by neurotensin at 10^-6M and 10^-5M concentration. It is concluded that neurotensin is able to modulate [³H]-ouabain binding, an effect which hardly involves NTS1 receptor.