Gln exits from the end feet and is untaken by Gln transporters, present on the juxtaposed abluminal membrane of capillary endothelial cells (Lee et al., 1998). Once into the endothelial cell, Gln is converted back to Glu via the endothelial glutaminase, which now diffuses into the blood by facilitative transport. Such a mechanism could also sub-serve a neurometabolic coupling (Jakovcevic and Harder, 2007). Under pathological conditions involving a brain insult such as ischemic stroke, traumatic brain injury or prolonged epileptic seizures, Glu is uncontrollably released from its neuronal and glial stores, via the reverse

operation of the excitatory amino acid transporters (EAATs) (Vesce et al., 2007). In these circumstances, excess Glu is also regulated by the transporters associated with the ubiquitous and dense network of brain capillaries, leading to excitotoxic neuronal death http://www.selleckchem.com/products/AZD6244.html in very large brain territories. One of the most severe acute neurological conditions, associated with excessive Glu release, is the status epilepticus (SE). SE is

defined as an epileptic seizure lasting more than 30 min or as intermittent seizures, lasting for more than 30 min, during which the patient does not recover consciousness between repeated episodes ( Leite et al., 2006). SE is one of the most common neurological emergencies and several prospective studies have reported an incidence of 10–20/100,000 amongst whites in Europe and the US ( Hesdorffer et al., 1998, Coeytaux et al., 2000 and Knake et al., 2001). Convulsive SE is the CAL-101 cell line commonest form, representing 40–60% of all SE cases. Mortality is high, with one out of five dying in the first 30 days ( Logroscino et al., 1997). The main neurological sequels of SE reported in the literature are cognitive impairment, brain damage-related found deficits, and long-term development of recurrent seizures ( Leite et al., 2006). Neurobiological substrate of SE-related brain damage includes the excitotoxic effect of excitatory amino acids, particularly Glu (Ben-Ari and Schwarcz, 1986, Choi, 1988 and Naffah-Mazzacoratti and Amado, 2002). Intense seizure activity

causes massive Ca2+ influx, which results in increased intracellular and intra-mitochondrial membrane depolarization, superoxide production and activation of caspases (Gupta and Dettbarn, 2003, Persike et al., 2008 and Henshall, 2007). The large increase in cytosolic Ca2+ evoked by activation of Glu receptors (NMDA and AMPA/kainate) seems to be a necessary step in the overall process of neuronal degeneration. This process triggers the acute neuronal cell death that occurs after SE (Maus et al., 1999, Fujikawa et al., 2000 and Men et al., 2000). Gottlieb et al. (2003) recently tested the hypothesis that a larger Glu concentration gradient between ISF/CSF and blood plasma could provide an increased driving force for the brain-to-blood Glu efflux.