Of the dentate gyrus. This unique process after epilepsy, called “mossy

Of the dentate gyrus. This unique process after epilepsy, called “mossy fiber sprouting”, can be identified by Timm staining of zinc [48]. Mossy fiber sprouting may result in recurrent excitatory circuits or stabilize the network by innervating inhibitory neurons. Dentate granule cell neurogenesis and seizure-induced hippocampal network reorganization in adult rodent raises the possibility of a relationship between these two phenomena. Given the data on continuing granule cell neurogenesis, Parent et al. showed that hippocampal plasticity associated with recurrent seizures is derived primarily from newly born granule cells rather than from existing and mature dentate granule cells [2,3]. To test the hypothesis that zinc is essential for neurogenesis, we used the chemical zinc chelator, CQ, to directly test the zinc deprivation effects on hippocampal neurogenesis. Our previous study described a transient increase of progenitor cells after hypoglycemia until 2 weeks after insult [4]. The reason for an increase in neurogenic activity at early time points after hypoglycemia is uncertain. Thus, we speculated that this transient increase of neurogenesis after seizure is related to synaptic release of zinc and cytolysis after dentate granule cell degeneration. Our present study demonstrates several zinc accumulating neurons in the dentate granule cell and hilar cell bodies after seizure. Previously we suggested that those zinc-accumulated neurons were degenerating after seizure [27]. We believe that continuous liberation of free zinc from the degenerating dentate granule cells or from mossy fiber synaptic terminals may chronically stimulate progenitor cell proliferation and support survival of neuroblast after hypoglycemia insult. Therefore, we tested the effects of zinc 117793 site chelation on basal neurogenesis as well as on seizure-induced transient neurogenesis. Continuous treatment with CQ for 1 week without seizure significantly decreased basal progenitor cell proliferation in the hippocampus compared to the vehicle treatedZinc and Hippocampal Neurogenesis after Seizuregroup, with a parallel reduction in the number of neuroblasts. Moreover, 1 week of continuous treatment with CQ after seizure also substantially reduced progenitor cell proliferation in the hippocampus. These results suggest that zinc in the brain modulates neurogenesis after epilepsy. However, a major concern regarding the use of CQ is that this chelator is not entirely zinc specific, since CQ also can chelate other transitional metals in the brain such as copper and iron [23]. To verify our present finding that reduction of neurogenesis by CQ treatment is solely due to depletion of extracellular zinc we will need a more specific zinc chelator for the future study. Another concern is that CQ may not only 1527786 act as a zinc chelator but also act as a zinc ionophore [49]. However, we speculate that CQ binds with chelatable (or free) zinc in the extracellular space and in the intracellular area, which depresses brain zinc availability to support neurogenesis either in the basal setting 1527786 act as a zinc chelator but also act as a zinc ionophore [49]. However, we speculate that CQ binds with chelatable (or free) zinc in the extracellular space and in the intracellular area, which depresses brain zinc availability to support neurogenesis either in the basal setting 16574785 or after seizure. To differentiate whether zinc chelation or zinc ionophore effect of CQ may cause counter neurogenesis alternatively we delivered N,N,N9,N9-tetrakis(2pyridylmethyl)ethylenediamine (TPEN) after seizure for 1 week. In the present study, we found that intracellular zinc chelator, TPEN, also significantly reduced seizure-induced neurogenesis.This finding is consistent with previous published s.