NEUROTENSIN DECREASES HIGH AFFINITY [3H]-OUABAIN BINDING TO CEREBRAL CORTEX MEMBRANES.

C. ROSIN; M.G. LOPEZ ORDIERES; G. RODRIGUEZ DE LORES ARNAIZ

Tandil, Pcia. de Buenos Aires

Congreso; XXXX Reunion Anual de la Asociacion Argentina de Farmacologia Experimental (SAFE),; 2008

Asociacion Argentina de Farmacologia Experimental (SAFE),

NEUROTENSIN DECREASES HIGH AFFINITY [3H]-OUABAIN BINDING TO CEREBRAL CORTEX MEMBRANES. Rosin C., L¨®pez Ordieres, M.G., Rodr¨ªguez de Lores Arnaiz, G. Inst Biol Cel y Neuroc ¡°Prof. E. De Robertis¡±, Fac Med, and C¨¢tedra de Farmacol, Fac Farm y Bioq, UBA. Paraguay 2155, 1121-Buenos Aires, Argentina. E-mail: grodrig@f fyb.uba.ar   Previous work showed that neurotensin inhibits synaptosomal membrane Na+, K+-ATPase activity, an effect blocked by SR 48692 (SANOFI-AVENTIS, US INC), antagonist for high affinity neurotensin receptor (NTS1). Neurotensin effect on high affinity [3H]ouabain binding was studied, to observe a dose-dependent decrease, with the following values (% vs control): 87 ¡À 10; 66 ¡À 5 and 22 ¡À 10 (n=3) at 10¨C6 M, 10¨C5 M and 10¨C4 M peptide concentration, respectively. SR 48692 at 10¨C6 M, 10¨C5 M and 10¨C4 M decreased [3H]ouabain binding (in %) to 96 ¡À 19; 85 ¡À 16 and 34 ¡À 17 (n = 3-6), respectively. Neurotensin at 10¨C6 M and 10¨C5 M concentration respectively decreased 15% and 30% binding to membranes after injection of SR 48692 (100 ¦Ìg/kg, icv, 30 min). It is concluded that neurotensin is able to modulate [3H]ouabain binding, an effect which hardly involves NTS1 receptor.