Differential expression of phospholipase D isozymes in the hippocampus following kainic acid-induced seizures. J. Neuropathol. Exp. Neurol. 63:812-820

Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Journal of Neuropathology and Experimental Neurology (Impact Factor: 3.8). 09/2004; 63(8):812-20. DOI: 10.1093/jnen/63.8.812
Source: PubMed


To investigate the pathophysiological role of phospholipase D (PLD)-mediated signaling, changes in the expression of the PLD isozymes PLD1 and PLD2 were investigated in the rat kainic acid (KA) model of human temporal lobe epilepsy. Western blot analysis showed a significant increase in the expression of PLD1 and PLD2 in the postictal hippocampus. PLD1 immunoreactivity increased preferentially in the CA3 and CA1 regions, where pyramidal neurons are susceptible to temporal lobe epilepsy. Experiments employing double immunofluorescence revealed that the cells expressing PLD1 were GFAP-expressing reactive astrocytes. By contrast, PLD2 immunoreactivity increased strikingly in infrapyramidal, but not in suprapyramidal granule cells of the postictal dentate gyrus, fitting well with results of the PLD activity assay. Considering that PLD belongs to a key signaling pathway, this result suggests that changes in granule cell activity in the dentate gyrus after seizures occurs specifically between the supra- and infrapyramidal blades. In addition, enhanced immunoreactivity of PLD2 was observed in the reactive astrocytes of the CA1, CA3, and hilar subregions, but its temporal pattern is different from that of PLD1. Taken together, our results suggest that PLD1 and PLD2 exercise their unique pathophysiological functions in the rat hippocampus after KA-induced seizures.

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    • "The mTOR pathway is activated in reactive astrocytes in spinal cord injury (Codeluppi et al., 2009). The levels of ERα in CA1 astrocytes and PLD were increased in KA model (Kim et al., 2004; Sakuma et al., 2009). ERK/MAPK is activated in mechanical trauma-induced astrogliosis and human reactive astrocytes (Mandell and VandenBerg, 1999; Mandell et al., 2001). "
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    • "Historically, no distinctions in the functional, structural , and neural innervation of the two blades of the dentate gyrus have been emphasized. However, more recent studies have identified a number of neurochemical, neuroanatomical, and functional differences between the two blades (Hartmann et al. 1992; Tamamaki 1997; Scharfman et al. 2002; Choi et al. 2003; Kim et al. 2004; Witter and Amaral 2004). "
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