Modulation of Nitric Oxide Synthase activity due to Prenatal Stress

MAUR, D.G.; BURDET, B; GENARO A.M; ZORRILLA ZUBILETE, M.A.

Huerta Grande, Cordoba, Argentina

Congreso; I Reunión Conjunta de Neurociencias; 2009

Sociedad Argentina de Investigación en Neurociencias y Taller Argentino de Neurociencias

During development animals are especially vulnerable to disturbances on homeostasis. We have previously shown that prenatal stress alters offspring´s behaviour. The objective of the present study was to evaluate the role of nitric oxide in these alterations. Methods: Pregnant Wistar rats were restrained three times a day, 45 minutes each, since 14th day of pregnancy until delivery. Offspring was analyzed for hippocampal nitric oxide synthase (NOS) activity and protein levels and PKC activity. Anxiety-like behaviour and habituation were evaluated in the Open Field and Territory Recognition was also studied. Results: Hippocampal neuronal NOS (nNOS) levels were increased in Prenatally Stressed (PS) animals at post-natal age 7 (PN7), almost twice as much as in Controls. Total NOS activity (pmol/mgtissue/30min) was unchanged, but endothelial NOS (eNOS) activity (obtained in the presence of a selective nNOS inhibitor) was significantly decreased and nNOS enhanced. Activity in the presence of EGTA (inducible NOS, iNOS) was almost undetectable in both groups. We found no differences in total PKC activity in hippocampus at PN7. We observed increased freezing in PS rats and impaired habituation to the Open Field and defects in Territory Recognition in males at PN60. Discussion: It has been described that an increased nNOS activity can affect hippocampal neurogenesis, and may induce neurodegeneration in a variety of animal models. The results reported here could point to a role of nNOS in the behavioural abnormalities described in PS rats.