Changes in NGF release during stressful events have been associated with the
activation of neurons expressing NGF receptors. This study examined the influence
of acute stress-induced stimulation on NGF/c-Fos colocalization in the
following limbic regions: the paraventricular (PV) nucleus of the hypothalamus,
medial (MeA) nucleus of the amygdala, and CA3 hippocampus. Juvenile
(P21) and aged rats (P360) were exposed to a 15-minute acute open field
(OF) test. Double immunofluorescence staining, used to detect NGF-ir and
c-Fos-ir cells, revealed a higher percentage of NGF/c-Fos-ir neurons in the P21
control group than in the P360 control group. Under OF acute stimulation,
a statistically significant (p < 0.05) increase of NGF/c-Fos level in CA3 of juvenile
animals and in PV and CA3 of the aged rats was observed. These observations
indicate that the investigated structures in both age groups show a different
response to acute OF stimulation. Acute OF affects the levels of NGF/c-Fos
more significantly in aged rats
