, 1997 and Chao et al , 2010), this correlation may embody a rele

, 1997 and Chao et al., 2010), this correlation may embody a relevant pathophysiological response to seizures (Ueda et al., 2002). Previous study had already been conducted on the

expression of glutamate transporters following kainate treatment during brain development and no differences were found for hippocampal GLT-1 mRNA levels 4, 8 and 16 h after kainate-induced seizures in rats at 7 days old (Simantov et al., 1999). These differences between the studies could be due to the required time course for changes in the mRNA expression (measured in the Ref. Simantov et al., 1999) and in the detection on the translated protein (measured in our study). Interestingly, GLAST was the only glutamate transporter in newborn rats treated selleck compound with kainate that remains up regulated and the find more same profile for GLAST mRNA levels was also observed in adult animals (Nonaka et al., 1998). Additionally, it is noteworthy that the glutamate uptake apparently follows the ontogeny of GLT-1 during brain development (Ullensvang et al., 1997). Although it remains to be determined if glutamate uptake in acutely isolated slices from rat pups could be related to nerve terminals, glial cells or both cellular compartments, a recent study reported that the uptake activity into acutely dissociated slices from adult animals was related to nerve terminals

rather than glial uptake (Furness et al., 2008). More investigations need to be performed helping to elucidate this topic. Our findings ruled out the participation of EAAC1 transporter in the kainate-induced seizures in newborns. Interestingly, the same could not be observed in adult animals submitted to kainate-induced isothipendyl seizures, since hippocampal EAAC1 mRNA expression remains increased up to 5 days after seizures (Nonaka et al., 1998). As the kainate toxicity depends on the release of endogenous excitatory amino acids (Ben-Ari, 1985, Coyle, 1983 and Sperk et al., 1983) and in vitro studies indicated

that glutamate stimulates glutamate transport in primary astrocyte cultures ( Gegelashvili et al., 1996), it can be hypothesized that the transient up regulation of both transporters could reflect an attempt to remove the excess of extracellular glutamate that accumulate during seizure periods ( Ueda et al., 2002). As the GLAST immunocontent was more specifically involved in short ( Duan et al., 1999) and prolonged ( Gegelashvili et al., 1996) stimulatory effect triggered by glutamate on its own uptake by cultured astrocytes, the longer lasting increase in the GLAST immunocontent after KA-induced seizures here observed (up to 48 h) could be interpreted as a neuroprotective response to the increase of hippocampal glutamate extracellular levels. It is interesting to note that the increase in the immunoreactivity for GFAP-positive astrocytes, which was measured 24 h after the end of seizures, accomplished the increase in the GLAST immunocontent.

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>