CEFYBO   02669
CENTRO DE ESTUDIOS FARMACOLOGICOS Y BOTANICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Reduction of nNOS expressing neurons in prenatally stressed male rats
Autor/es:
DG MAUR; B BURDET; H RIOS; AM GENARO; MA ZORRILLA ZUBILETE
Reunión:
Congreso; XXVIII Congreso de la Sociedad Argentina de Investigación en Neurociencias; 2013
Resumen:
A great amount
of evidence has shown that prenatal restraint stress (PRS) induces alterations in learning and memory. However,
the molecular mechanisms underlying these changes are partially understood.
Nitric oxide (NO) is a small, diffusible and rapidly acting molecule involved
in many physiological processes, such as long term potentiation (LTP) in the
hippocampus, corticosterone secretion regulation, learning and memory
formation, among others. Previous research in our laboratory has shown that PRS
induces changes in cerebellar nitric oxide synthase expression, and these
changes were correlated with an impaired spatial memory performance. Still, no published
research has explored the role of hippocampal NO in PRS.
The aim of the
present work was to evaluate the role of nitric oxide in the behavioural
alterations induced by PRS.
Methods:
pregnant Wistar rats were restrained in plastic devices three times a day
during the last week of pregnancy. Its male offspring was evaluated at 90 days
of age (PN90) for associative learning in the inhibitory avoidance task, and
locomotor activity and habituation in the open field. Another set of control
(C) and PRS animals was used for neuronal nitric oxide synthase (nNOS) and
glucocorticoid receptor (GR) immunohistochemistry and for NADPH diaphorase
histochemistry.
Results: We
found an impairment in associative learning in PRS rats. No differences in
locomotor activity and habituation memory were found. Light microscope
observation of slices obtained by immunohistochemistry showed a decrease of
nNOS and GR expression, both in Cornus Ammon 1 (CA1) and Dentate Gyrus (DG)
hippocampal subregions. We also found a decrease in NADPH diaphorase positive
neurons in PRS rats.
Discussion: Our results show impairments in associative memory, with no changes in
habituation to a novel environment. Extensive evidence has shown a role for NO
in associative learning, and recent published papers have involved GR
hippocampal expression with inhibitory avoidance learning. Moreover, recent
evidence has shown that nitric oxide is necessary for corticosterone (cort)
secretion, and that there is a direct relation between cort secretion due to contextual
fear conditioning and subsequent learning. Here we show a decrease in nNOS and
GR expression in adult PRS rats, both in hippocampal CA1 and DG subregions. The
results found here point to a role of nitric oxide in the behavioural
alterations induced by PRS.