Neonatal X radiation: hippocampal morphology and anxiety state

LUCILA GUADALUPE CACERES; CID MARIANA PAULA; GUSTAVO EZEQUIEL SARACENO; JUAN IGNACIO ROMERO; SOLEDAD LUCÍA URAN; FRANCISCO CAPANI; SALVATIERRA NANCY ALICIA; LAURA RUTH GUELMAN

Congreso; XXVI Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia; 2011

Ionizing radiation (Rx) is a physical agent broadly used in therapeutic medicine, being the developing Central Nervous System particularly vulnerable. Since a decrease in anxiety levels has been observed in neonatally irradiated rats, which could underlie several memory changes, and considering an implication of GABA in both mechanisms, the aim of the present work was to address the involvement of the GABAergic system in these Rx-induced alterations. Moreover, since a relationship between dendritic spines, GABAergic neurotransmission and memory processes have been postulated, the density of dendritic spines in the hippocampus (Hip) was also assessed. Male Wistar rats were irradiated with 5 Gy of X rays in their cephalic ends between 24 and 48 hours after birth. GABAA receptor binding assay and morphological assessment of mushroom dendritic spines were performed in Hip of 30-days-old rats. Results show that the decrease in anxiety levels observed in irradiated rats is correlated with an increase of GABAA receptor density observed in synaptosomes from Hip of irradiated rats. Moreover, the increase in the number of mushroom dendritic spines Faloidine (+) in CA1 region of the Hip of irradiated group could explain, at least in part, the increase of GABAA receptor density.