NEONATAL NITRIC OXIDE SYNTHASE INHIBITION MODIFIES NEUROTENSIN EFFECT ON NEURONAL ATPase ACTIVITY.

M. G. LÓPEZ ORDIERES; A ÁLVAREZ JULIÁ; G. KEMLING; G. RODRÍGUEZ DE LORES ARNAIZ

Tandil, Pcia. de Buenos Aires

Congreso; XXXX Reunión Anual de la Asociación Argentina de Farmacología Experimental (SAFE); 2008

Asociación Argentina de Farmacología Experimental (SAFE)

In previous work, we showed that peptide neurotensin inhibits neuronal Na+, K+-ATPase activity, an effect which involves high affinity neurotensin receptor, (NTS1). Nitric oxide (NO), is produced from L-arginine and it acts as a neurotransmitter or neuromodulator when is synthesized by the neuronal enzyme nitric oxide synthase (nNOS); NO has a short action time and the inhibitors of NOS became a way to study NO system function. Herein we evaluated neurotensin effect on cortical synaptosomal membranes isolated from female or male Sprague-Dawley rats; these rats were injected (s.c.) on 3, 4, and 5 postnatal days with saline (control) or, L-No-Arg, a nitric oxide synthase inhibitor (iNOS).  In membranes, 3.5 x 10-8- 3.5 x 10-6 M neurotensin failed to modify Na+, K+-ATPase activity, whereas a decrease 6%-34% in enzyme activity were recorded in control animals. [3H]-ouabain binding assay, demonstrated that 3.5 x 10-6 M neurotensin added to cortical membranes isolated from iNOS male injected and control animals decreased specific ouabain- binding in 37% and 8 % respectively. Therefore, NO dysfunction during the early postnatal period that could influence the maturation and the synaptogenesis of cortical neurons, also produce an alteration on neurotensin system.