Analysis of standard activation of neurons doubly scored for Fos and urocortin in the Edinger-Westphal nucleus after acute stress of the natural predator exposure in male rats and lactating female rats deprived of the puppies

Abstract

Studies have demonstrated the participation of urocortin 1 (Ucn1) during the adaptation to stressful stimuli. This hypothesis was first raised by the research group of Majzoub (Weninger et al., 2000) and Kozicz (Kozicz et al., 2001), which report that acute pain by containment can mobilize Ucn 1 neurons and additionally lead to increased expression of its mRNA. Subsequent studies have revealed that activation of Ucn neurons is factor-specific stress in rats (Gaszner et al., 2004). The most dominant site of Ucn-immunoreactivity in the rat brain is the Edinger-Westphal nucleus (EW) (Bittencourt et al. 1999; Kozicz et al. 1998) and also neuroanatomical studies have demonstrated the complexity of ascending and descending projections of the EW to nonoculomotor brain areas (Loewy et al. 1978; Sugimoto et al. 1982; Bittencourt et al. 1999), suggesting that this nucleus is also involved in the control of a diversity of important biological functions. Among the different experimental models are used to generate a state of acute stress, we propose to investigate the activation pattern of neurons doubly labeled for Fos and Ucn in the EW nucleus of the male rats subjected to stress from a confrontation with the natural predator (cat) for 10 minutes and further generate the stress response in lactating rats deprived of puppies for two hours.(AU)