Helen Benveniste

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Rats were implanted with 0.3-mm-diameter dialysis tubing through the hippocampus and subsequently perfused with Ringer's solution at a flow rate of 2 microliter/min. Samples of the perfusate representing the extracellular fluid were collected over 5-min periods and subsequently analyzed for contents of the amino acids glutamate, aspartate, glutamine,(More)
Microdialysis tubes, used for measurements of extracellular neurotransmitter concentrations, were implanted in rat dorsal hippocampus to study the adjacent tissue reaction. The brain was examined 1–60 days after the implantation. Within the first 2 days, normal neuropil and only occasional hemorrhage surrounded the microdialysis tube. Three days following(More)
Local cerebral glucose metabolism (LCMRglc) and local cerebral blood flow (LCBF) were studied following implantation of a microdialysis fiber in rat dorsal hippocampus. Recovery time after implantation varied from 0 to 24 h. All rats showed pronounced disturbances in LCMRglc and LCBF during the first 2 h of implantation. The changes consisted of (a) a(More)
The uptake and release of D-[3H]aspartate (used as a tracer for endogenous glutamate and aspartate) were studied in cultured glutamatergic neurons (cerebellar granule cells) and astrocytes at normal (5 mM) or high (55 mM) potassium and under conditions of hypoglycemia, anoxia or "ischemia" (combined hypoglycemia and anoxia). In glutamatergic neurons it was(More)
Rats exposed to 10 min of complete cerebral ischemia develop necrosis of the CA-1 region of the hippocampus after 2-3 days. We studied the involvement of synaptic transmission for this process by ablation of the afferent input (which is mainly glutamatergic) to CA1 by bilateral destruction of CA-3 neurons (Schafferotomi). The deafferentiation completely(More)
Apolipoprotein E has been implicated in modifying neurological outcome after traumatic brain injury, although the mechanisms by which this occurs remain poorly defined. To investigate the role of endogenous apolipoprotein E following acute brain injury, noninvasive magnetic resonance imaging was performed on anesthetized mice following closed head injury.(More)
The distribution of brain cell injury following transient ischemia is remarkable because only certain neurons in distinct brain regions are destroyed (selective neuronal death). Because excitatory neurotransmitters (glutamate and aspartate) cause a similar pattern of selective neuronal death, it seemed only natural to associate these effects with the trauma(More)
Microdialysis is an extensively used technique for the study of solutes in brain interstitial space. The method is based on collection of substances by diffusion across a dialysis membrane positioned in the brain. The outflow concentration reflects the interstitial concentration of the substance of interest, but the relationship between these two entities(More)
The removal of glutamatergic afferents to CA1 by destruction of the CA3 region is known to protect CA1 pyramidal cells against 10 min of transient global ischemia. To investigate further the pathogenetic significance of glutamate, we measured the release of glutamate in intact and CA3-lesioned CA1 hippocampal tissue. In intact CA1 hippocampal tissue,(More)