Neuroreport
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Glutamate transporters are essential for the homeostasis of glutamate and normal function of glutamatergic synapses. Their function was shown to be regulated by redox agents and dimerizations that involves redox changes of cysteine residues. ⋯ Among them is the toxin Tx3-4, from the spider Phoneutria nigriventer, which is able to inhibit glutamate uptake in rat hippocampal synaptosomes. Based on results obtained with manipulation of the redox state of cysteine residues in synaptosomes and in Tx3-4, we suggest that the effect of this toxin on glutamate uptake is due to interactions that involve cysteines both in the toxin and in the transporters.
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We examined the impact of spinal cord injury to a depth of 0.5 mm at L1-L2 (upper lumbar cord injury) and in L6-S1 (lower cord injury) in Wistar rats. Upper lumbar cord injury resulted in the disappearance of the motor evoked potential (MEP) of the gastrocnemius muscle during transcranial magnetic stimulation, while the threshold was decreased in rats with lower cord injury. ⋯ In lower cord injury, the pattern of H-response recruitment curves differed from that in controls. Our results indicated that MEP and the spinal reflex are influenced not only by upper lumbar cord injury but also by lower cord injury.