Relative to Flt-1 baseline expression in sham control, in PNV-treated animals the upregulation of Flt-1 was progressive GSK J4 price with time in P14 and adult

animals, achieving its climax 24 h after envenoming. Actually, just in the CA2 of young animals Flt-1 was unchanged 24 h-post PNV exposure. Despite, clinically the signs of envenoming seemed to be resolved after 12 h of PNV envenomation. The findings indicate that at molecular level the effects of venom were still underway. On the other hand, the expressional steady state of anti-Flt-1 labeling seen in neurons of all four hippocampal regions of animals injected with saline appears to suggest that stressing factors (animal’s manipulation and i.p. injection) did not influence the level of the receptor. Both in P14 and adult animals the Flt-1

expression level remained with minimal variation (see white bars of Fig. 4). The basal expression of Flt-1 in P14 animals was higher than in adult animals. The fact that the vasogenic edema caused by PNV correlates with significant upregulation of the VEGFR1 receptor, Flt-1, can be seen as a strong evidence indicating this receptor as a mediator of the neurotoxic effects of PNV in hippocampus of P14 neonate rats and adult rats. It also suggests that neuron cells are important targets for PNV. VEGF is a growth factor which plays a central neurotrophic and neuroprotective role in the CNS by promoting angiogenesis, vascular permeability, regulation of vasculogenesis Immune system and neurogenesis, both during development and after ischemia or trauma (Hansen et al., 2008). In hippocampus, VEGF and Flt-1 and Flk-1 receptors are upregulated Raf inhibitor after transient ischemia (Choi et al., 2007). Neurogenesis in the adult mammalian brain is mainly confined to two regions: the subventricular zone

of the lateral ventricles and the dentate gyrus of the hippocampus (Altman and Das, 1965; Cameron et al., 1993; Levison and Goldman, 1993; Luskin, 1993). This may reflect why DG neurons of sham and treated group exhibited the highest expression when compared with the other hippocampal regions. The dentate gyrus region is thought to contribute the formation for new memories, exploratory activity and synaptic plasticity (Saab et al., 2009). The hippocampus is part of the lymbic system and is a region of the cerebral cortex. CA1, CA3 and DG, the three best explored regions of the hippocampus, are believed to function cooperatively; however evidences indicate that each one performs particular specialized functional activities (Klausberger and Somogyi, 2008). The implications behind the highest increase of Flt-1 in DG (420%), followed by CA3 (∼290%) after PNV administration are unclear. Further studies aimed to associate venom effects on Flt-1 expression with specific operational function of each hippocampal region will be useful for therapeutic strategies.